Astronomy Picture of the Day |
APOD: 2024 September 10 – Horsehead and Orion Nebulas
Explanation:
The dark Horsehead Nebula and the glowing
Orion Nebula are contrasting cosmic vistas.
Adrift 1,500 light-years away in one of
the night sky's
most recognizable
constellations,
they appear in opposite corners of the above
stunning mosaic.
The familiar Horsehead
nebula appears as a dark cloud, a
small silhouette
notched against the long glow of hydrogen -- here shown in gold -- at the lower left.
Alnitak is the easternmost star in
Orion's belt and is seen as the bright
star to the left of the
Horsehead.
Just below Alnitak is the
Flame Nebula, with clouds of
bright emission and
dramatic dark dust lanes.
The magnificent emission region, the
Orion Nebula (aka M42), lies at the upper right.
Immediately to its left is a prominent
reflection nebula sometimes called the Running Man.
Pervasive tendrils
of glowing hydrogen gas are easily
traced
throughout the region.
APOD: 2024 January 31 – Camera Orion Rising
Explanation:
What does Orion rising look like to a camera?
During this time of the year, the
famous constellation is visible to the southeast just after sunset.
From most
Earthly locations,
Orion's familiar star pattern,
highlighted by the
three-stars-in-a-row belt stars,
rises sideways.
An entire section of the night sky
that includes Orion was photographed rising above
Śnieżka, a
mountain
on the border between
Poland
and the
Czech Republic.
The long duration exposure sequence brings
up many faint features including the
Orion and
Flame Nebulas,
both encompassed by the curving
Barnard's Loop.
The
featured
wide-angle
camera composite
also captured night sky icons including the blue
Pleiades
star cluster at the image top and the red
Rosette Nebula to the left of Orion.
Famous stars in the frame include Procyon,
Betelgeuse,
Rigel and
Aldebaran.
Orion will appear successively higher in the sky at
sunset during the coming months.
APOD: 2024 January 16 – The Orion You Can Almost See
Explanation:
Do you recognize this constellation?
Although it is one of the
most recognizable star groupings on the sky,
this is a
more full Orion than you can see --
an Orion only revealed with long exposure digital
camera imaging and
post-
processing.
Here the cool
red giant
Betelgeuse
takes on a strong orange tint as the brightest star on the upper left.
Orion's hot blue stars are numerous, with
supergiant
Rigel balancing Betelgeuse on the lower right, and
Bellatrix at the upper right.
Lined up in
Orion's belt are three stars
all about 1,500
light-years away,
born from the constellation's well-studied
interstellar clouds.
Just below Orion's belt is a bright but fuzzy patch that might also
look familiar -- the stellar nursery known as
Orion's Nebula.
Finally, just barely visible to the
unaided eye but quite striking here is
Barnard's Loop -- a huge gaseous emission nebula surrounding Orion's Belt and Nebula discovered over 100 years ago by the pioneering Orion photographer
E. E. Barnard.
APOD: 2024 January 5 - Trapezium: At the Heart of Orion
Explanation:
Near the center of
this sharp cosmic portrait, at
the heart of the Orion Nebula,
are four hot, massive stars
known as
the Trapezium.
Gathered within a region about 1.5 light-years in radius,
they dominate the core of the dense Orion Nebula Star Cluster.
Ultraviolet
ionizing radiation from the
Trapezium stars,
mostly from the brightest star
Theta-1 Orionis C
powers the complex star forming region's entire visible glow.
About three million years old, the Orion Nebula Cluster was
even more compact in its younger years and a
dynamical study
indicates that
runaway stellar collisions
at an earlier age may have formed a
black hole
with more than 100 times the mass of the Sun.
The presence of a
black hole within the cluster
could explain the observed high velocities of the
Trapezium stars.
The Orion Nebula's distance of some 1,500 light-years would make it one
of the
closest known black holes
to planet Earth.
APOD: 2023 December 7 - Orion and the Ocean of Storms
Explanation:
On December 5, 2022,
a camera on board the uncrewed Orion spacecraft captured
this view as Orion
approached its return powered flyby of the Moon.
Beyond one of Orion's extended solar arrays
lies dark, smooth, terrain along the
western edge of the Oceanus Procellarum.
Prominent on the lunar nearside
Oceanus Procellarum,
the Ocean of Storms, is the largest of the
Moon's lava-flooded maria.
The lunar terminator, shadow line between lunar night and day,
runs along the left of this frame.
The 41 kilometer diameter
crater Marius
is top center, with ray
crater Kepler
peeking in at the edge, just right of the solar array wing.
Kepler's bright rays extend to the north and west, reaching the
dark-floored Marius.
By December 11, 2022 the Orion spacecraft had
reached its home world.
The historic Artemis 1 mission ended with Orion's successful splashdown in
planet Earth's
water-flooded Pacific Ocean.
APOD: 2023 November 18 - Planet Earth from Orion
Explanation:
One year ago
a Space Launch System rocket left planet Earth
on November 16, 2022 at 1:47am EST carrying the Orion spacecraft on the
Artemis I mission, the first integrated test of NASA’s deep space
exploration systems.
Over an hour after
liftoff from Kennedy Space Center's
historic
Launch Complex 39B, one of Orion's
external video cameras
captured this view of its new
perspective from space.
In the foreground are Orion's Orbital Maneuvering System engine
and auxillary engines,
at the bottom of the European Service Module.
Beyond one of the module's 7-meter long extended solar array wings
lies the spacecraft's
beautiful home world.
Making close flybys of the
lunar surface and reaching a
retrograde orbit 70,000 kilometers beyond the Moon, the
uncrewed Artemis I mission
lasted over 25 days,
testing capabilities to enable human exploration of the Moon and Mars.
Building on the
success
of Artemis I,
no earlier than November 2024
the Artemis II mission
with a crew of 4 will venture around the Moon and back again.
APOD: 2023 October 10 – Hidden Orion from Webb
Explanation:
The Great Nebula in Orion has hidden stars.
To the unaided eye in visible light, it appears as a small
fuzzy patch in the
constellation of Orion.
But this image was taken by the
Webb Space Telescope
in a representative-color composite of red and very near
infrared light.
It confirms with impressive detail that the
Orion Nebula is a busy neighborhood of
young stars, hot gas, and dark dust.
The rollover image
shows the same image in representative colors further into the
near infrared.
The power behind much of the
Orion Nebula (M42) is the
Trapezium -
a cluster of bright stars near the nebula's center.
The diffuse and
filamentary glow
surrounding the bright stars is mostly heated interstellar
dust.
Detailed inspection of these images shows an
unexpectedly large number of Jupiter-Mass Binary Objects
(JuMBOs), pairs of Jupiter-mass
objects which might give a clue to how stars are forming.
The whole
Orion Nebula cloud complex, which
includes the
Horsehead Nebula,
will slowly disperse over the next few million years.
APOD: 2023 March 10 - Orion and the Running Man
Explanation:
Few cosmic vistas excite the imagination like
The Great Nebula in Orion.
Visible as a faint celestial smudge
to the naked-eye,
the nearest large star-forming region sprawls across
this sharp telescopic image,
recorded on a cold January night in dark skies
from West Virginia, planet Earth.
Also known as
M42,
the Orion Nebula's glowing gas surrounds
hot, young stars.
About 40 light-years across, it lies at the edge of an immense interstellar
molecular cloud
only 1,500 light-years away
within the same spiral arm of our Milky Way galaxy as the Sun.
Along with dusty bluish reflection nebula
NGC 1977 and friends
near the top of the frame,
the eye-catching nebulae represent only a
small fraction of our
galactic neighborhood's
wealth of star-forming material.
Within the well-studied stellar nursery,
astronomers have also identified
what appear to be numerous
infant solar systems.
APOD: 2022 December 8 - Orion and the Ocean of Storms
Explanation:
A camera on board the uncrewed Orion spacecraft captured
this view on December 5
as Orion approached its return powered
flyby of the Moon.
Below one of Orion's extended solar arrays lies dark, smooth,
terrain along the
western edge of the Oceanus Procellarum.
Prominent on the lunar nearside
Oceanus Procellarum,
the Ocean of Storms, is the largest of the
Moon's lava-flooded maria.
The lunar terminator, shadow line between lunar night and day,
runs along the left of the frame.
The 41 kilometer diameter
crater Marius
is top center, with ray
crater Kepler
peeking in at the edge, just right of the solar array wing.
Kepler's bright rays extend to the north and west, reaching the
dark-floored Marius.
Of course the
Orion spacecraft is now headed toward a
December 11 splashdown in
planet Earth's
water-flooded Pacific Ocean.
APOD: 2022 November 28 - Leonid Meteors Through Orion
Explanation:
Where will the next meteor appear?
Even during a meteor shower, it is practically impossible to know.
Therefore, a good way to enjoy a
meteor shower is to find a place where you can
sit comfortably and monitor a great expanse of dark sky.
And it may be satisfying to share this experience with a friend.
The meteor shower depicted was the 2022
Leonids which peaked earlier this month, and the view is from
Hainan,
China looking out over the
South China Sea.
Meteor streaks captured over a few hours were isolated and added to a foreground image recorded earlier.
From this place and time,
Leonid meteors that
trace back to the
constellation of Leo
were seen streaking across
other constellations including
Orion.
The bright red planet
Mars appears near the top of the image.
Bonding over their love of astronomy, the two pictured meteor enthusiasts, shown celebrating their
common birthday this month, are now married.
APOD: 2022 November 23 - Earthset from Orion
Explanation:
Eight billion people
are about to disappear in this
snapshot from space.
Taken on November 21, the
sixth day of the Artemis 1 mission,
their home world is setting behind the Moon's bright edge as viewed by an
external camera
on the outbound Orion spacecraft.
The Orion was headed for a powered flyby that
took it to within 130 kilometers of the lunar surface.
Velocity gained in the flyby maneuver will be used to reach a
distant retrograde orbit
around the Moon.
That orbit is considered distant because it's another 92,000 kilometers
beyond the Moon, and retrograde because the spacecraft will
orbit in the opposite direction of the Moon's orbit around planet Earth.
Orion will enter its distant retrograde orbit on Friday, November 25.
Swinging around the Moon,
Orion will reach a maximum distance (just over 400,000 kilometers)
from Earth on Monday November 28 exceeding a record set by
Apollo 13 for most distant
spacecraft designed for
human space exploration.
APOD: 2022 November 17 - Planet Earth from Orion
Explanation:
A Space Launch System rocket left planet Earth
on Wednesday, November 16 at 1:47am EST carrying the Orion spacecraft on the
Artemis 1 mission, the first integrated test of NASA’s deep space
exploration systems.
Over an hour after
liftoff from
Kennedy Space Center's
historic
Launch Complex 39B,
one of Orion's
external video cameras
captured this view of its new perspective
from space.
In the foreground are Orion's Orbital Maneuvering System engine
and auxillary engines,
at the bottom of the European Service Module.
Beyond one of the module's 7-meter long extended solar array wings
lies the spacecraft's
beautiful home world.
The Artemis 1 mission
will last almost four weeks,
testing capabilities to enable human exploration of the Moon and Mars.
The uncrewed Orion spacecraft is
expected to fly by the Moon
on November 21, performing a close approach to the
lunar surface on its way to a
retrograde orbit 70,000 kilometers beyond the Moon. Â
APOD: 2022 April 16 - Orion Pines
Explanation:
Taken with a camera fixed to a tripod, many short exposures
were aligned with the stars to unveil this beautiful, dark night sky.
Captured near
the rural village of Albany`a
at the northeastern corner of Spain, the three
stars of Orion's belt stretch across top center in the starry frame.
Alnitak, the easternmost (left) of the
belt stars is seen next to the more diffuse glow of the
Flame Nebula
and the dark notch of the famous Horsehead.
Easily visible to the naked-eye
The Great Nebula of Orion
is below the belt stars.
A mere 1,500 light-years distant, it is the closest large
stellar nursery to our fair planet.
Best seen in photographs, the broad and faint arc of
Barnard's Loop seems to
embrace Orion's brighter
stars and nebulae though.
In the northern spring the familiar
northern winter constellation
is setting.
Near the western horizon toward lower right Orion's
apparently bright
blue supergiant Rigel just touches the branches of a pine tree.
APOD: 2022 March 7 - A Lion in Orion
Explanation:
Yes, but can you see the lion?
A deep exposure shows the famous
dark indentation that looks like a
horse's head, visible just left and below center, and
known unsurprisingly as the Horsehead Nebula.
The Horsehead Nebula (Barnard 33) is part of a
vast complex of dark absorbing
dust and bright
glowing gas.
To bring out details of the
Horsehead's pasture,
an astrophotographer artistically combined light
accumulated for over 20 hours in
hydrogen (orange),
oxygen (blue), and
sulfur (green).
The resulting spectacular picture
captured from Raachine,
Lebanon,
details an intricate
tapestry of gaseous wisps
and dust-laden
filaments that were created and
sculpted over eons by
stellar winds and
ancient supernovas.
The featured composition brings up another
pareidolic
animal icon -- that of a lion's head --
in the expansive orange colored gas above the horse's head.
The Flame Nebula
is visible just to the left of the Horsehead.
The Horsehead Nebula lies 1,500
light years distant towards the constellation of
Orion.
APOD: 2022 February 23 - Orion over Green Bank
Explanation:
What will the huge Green Bank Telescope discover tonight?
Pictured, the
Robert C. Byrd Green Bank Telescope (GBT)
on the lower right is the largest fully-pointable single-dish
radio telescope in the world.
With a central dish larger than a football field, the
GBT
is nestled in the hills of
West Virginia,
USA in a
radio quiet zone where the use of cell phones, WiFi emitters,
and even microwave ovens are limited.
The GBT explores our universe
not only during the night -- but during the day, too,
since the daytime sky is typically dark in
radio waves.
Taken in late January, the featured image was planned for months to get the setting
location of Orion just right.
The image is a composite of a foreground shot taken over
a kilometer away from the
GBT,
and a background shot built up of long exposures during the previous night.
The deep background image of
Orion
is fitting
because the GBT is famous for, among
many discoveries,
mapping the
unusual magnetic field in the
Orion Molecular Cloud Complex.
APOD: 2022 January 27 - South of Orion
Explanation:
South of the large star-forming region known as the
Orion Nebula, lies bright blue reflection nebula
NGC 1999.
At the edge of the
Orion molecular
cloud complex some 1,500 light-years distant, NGC 1999's
illumination is provided by the embedded variable star V380 Orionis.
The nebula is marked with a dark sideways T-shape at center right in
this telescopic vista
that spans about two full moons on the sky.
Its dark shape was once assumed to
be an obscuring dust cloud seen in silhouette.
But infrared data
suggest the shape is likely a hole blown through the nebula
itself by energetic young stars.
In fact,
this region abounds
with energetic young stars
producing jets and outflows with luminous shock waves.
Cataloged as Herbig-Haro (HH) objects, named for astronomers
George Herbig and Guillermo Haro,
the shocks have intense reddish hues.
HH1 and HH2 are just below and right of NGC 1999.
HH222, also known as the
Waterfall nebula,
looks like a red gash near top right in the frame.
To create the shocks stellar jets push through
the surrounding material at speeds of
hundreds of kilometers per second.
APOD: 2022 January 18 - From Orion to the Southern Cross
Explanation:
This is a sky filled with glowing icons.
On the far left is the familiar
constellation of Orion, divided by its iconic three-aligned
belt stars and featuring the famous
Orion Nebula, both partly encircled by
Barnard's Loop.
Just left of center in the featured image is the brightest star in the night:
Sirius.
Arching across the image center is the central band of our
Milky Way Galaxy.
On the far right, near the top, are the two brightest
satellite galaxies of the Milky Way: the
Large Magellanic Cloud (LMC), and the
Small Magellanic Cloud (SMC).
Also on the far right -- just above the cloudy horizon -- is the
constellation of Crux,
complete with the four stars that make the iconic
Southern Cross.
The featured image is a composite of 18 consecutive exposures
taken by the same camera and from the same location in eastern
Australia
during the last days of last year.
In the foreground, picturesque basalt columns of the
Bombo Quarry part to
reveal the vast
Pacific Ocean.
APOD: 2021 October 6 - M43: Streams of Orion
Explanation:
Where do the dark streams of dust in the Orion Nebula originate?
This part of the
Orion Molecular Cloud
Complex,
M43,
is the often imaged but rarely mentioned neighbor
of the more famous M42.
M42, seen in part
to the upper right, includes many bright stars from the
Trapezium star
cluster.
M43
is itself a star forming region that displays intricately-laced
streams of dark dust -- although it is really composed mostly of glowing
hydrogen gas.
The entire
Orion field is located about 1600
light years away.
Opaque to visible light, the picturesque dark
dust is
created in the outer atmosphere of massive cool stars and expelled by strong
outer winds of
protons and
electrons.
APOD: 2021 July 7 - Flight Through the Orion Nebula in Infrared Light
Explanation:
What would it look like to fly into the Orion Nebula?
The exciting dynamic visualization
of the Orion Nebula is based on real
astronomical data
and adept movie rendering techniques.
Up close and personal with a famous stellar nursery
normally seen
from 1,500 light-years away, the digitally modeled
representation based is based on
infrared data from the
Spitzer Space Telescope.
The perspective moves along a valley over a
light-year wide, in the wall of the region's giant
molecular cloud.
Orion's valley ends in a cavity carved by the energetic
winds and
radiation of the massive central stars of the
Trapezium star cluster.
The entire Orion Nebula spans about 40
light years
and is located in the same spiral arm of our Galaxy as
the Sun.
APOD: 2021 June 29 - Orion Nebula: The Hubble View
Explanation:
Few cosmic vistas excite the imagination like
the Orion Nebula.
Also known as
M42,
the nebula's glowing gas surrounds hot young stars at the edge of an
immense interstellar
molecular cloud only 1,500 light-years away.
The Orion Nebula offers one of the best opportunities to study how
stars are born partly because it is the nearest large
star-forming region,
but also because the nebula's
energetic stars have blown away
obscuring gas and dust clouds that would otherwise block our view -
providing an intimate look at a range of ongoing stages
of starbirth and evolution.
The featured image of the
Orion Nebula is among the sharpest ever, constructed using data from the
Hubble Space Telescope.
The entire Orion Nebula spans about 40
light years
and is located in the same spiral arm of our Galaxy as
the Sun.
APOD: 2021 June 1 - Satellites over Orion
Explanation:
What are those streaks across Orion?
They are reflections of sunlight from numerous Earth-orbiting satellites.
Appearing by eye as a series of
successive points floating across
a twilight sky, the increasing number of communications satellites, including
SpaceX Starlink satellites, are
causing concern among many astronomers.
On the positive side,
Starlink and
similar constellations make the post-sunset sky more dynamic,
satellite-based global communications faster, and help provide
digital services to currently underserved rural areas.
On the negative side, though, these
low Earth-orbit satellites make
some deep astronomical imaging programs more difficult,
in particular observing programs that need images taken
just after sunset and just before dawn.
Planned future satellite arrays that function in higher orbits may
impact investigations of the deep universe planned for
large ground-based telescopes at any time during the night.
The streaks across Orion are not from Starlink but rather satellites
in high
geosynchronous orbit.
The featured picture, taken in 2019 December, is a digital combination of over 65 3-minutes exposures, with some images taken to highlight the background
Orion Nebula, while others to feature the passing satellites.
APOD: 2021 May 11 - Lightning and Orion Beyond Uluru
Explanation:
What's happening behind Uluru?
A United Nations World Heritage Site,
Uluru
is an extraordinary 350-meter high mountain in central
Australia
that rises sharply from nearly flat surroundings.
Composed of sandstone, Uluru has
slowly formed over the past 300 million years as softer rock eroded away.
In the background of the featured image taken in mid-May,
a raging thunderstorm is visible.
Far behind both
Uluru and the
thunderstorm is a
star-filled sky highlighted by the constellation of Orion.
The Uluru region has been a
home to humans for
over 22,000 years.
Local
indigenous people have long noted that when the
stars that compose the
modern constellation of Orion first appear in the night sky, a
hot season involving
lightning storms will soon be arriving.
APOD: 2021 May 9 - Horsehead and Orion Nebulas
Explanation:
The dark Horsehead Nebula and the glowing
Orion Nebula are contrasting cosmic vistas.
Adrift 1,500 light-years away in one of
the night sky's
most recognizable
constellations,
they appear in opposite corners of the above
stunning mosaic.
The familiar Horsehead
nebula appears as a dark cloud, a
small silhouette
notched against the long red glow at the lower left.
Alnitak is the easternmost star in
Orion's belt and is seen as the brightest
star to the left of the
Horsehead.
Below Alnitak is the
Flame Nebula, with clouds of
bright emission and
dramatic dark dust lanes.
The magnificent emission region, the
Orion Nebula (aka M42), lies at the upper right.
Immediately to its left is a prominent
reflection nebula sometimes called the Running Man.
Pervasive tendrils
of glowing hydrogen gas are easily
traced
throughout the region.
APOD: 2021 March 22 - From Auriga to Orion
Explanation:
What's up in the sky from Auriga to Orion?
Many of the famous stars and nebulas in this region were captured on 34 separate images,
taking over 430 hours of exposure, and digitally combined to reveal the
featured image.
Starting on the far upper left, toward the constellation of Auriga (the Chariot driver), is the picturesque
Flaming Star Nebula (IC 405).
Continuing down along the bright arc of our
Milky Way Galaxy, from left to right crossing the
constellations of the Twins and the Bull, notable appearing nebulas include the
Tadpole,
Simeis 147,
Monkey Head,
Jellyfish,
Cone and
Rosette nebulas.
In the upper right quadrant of the image,
toward the constellation of Orion (the hunter),
you can see
Sh2-264,
the half-circle of Barnard's Loop, and the
Horsehead and
Orion nebulas.
Famous stars in and
around Orion include, from left to right, orange
Betelgeuse (just right of the image center), blue
Bellatrix (just above it), the
Orion belt stars of Mintaka, Alnilam, and Alnitak,
while bright Rigel appears on the far upper right.
This stretch of sky
won't be remaining up
in the night very long -- it will be setting
continually earlier in the evening as
mid-year approaches.
APOD: 2020 November 12 - Comet ATLAS and Orion's Belt
Explanation:
With its closest approach to planet Earth scheduled for November 14,
this Comet ATLAS (C/2020 M3) was discovered just this summer,
another comet found by the NASA funded
Asteroid Terrestrial-impact Last Alert System.
It won't get as bright
as Comet NEOWISE
but it can still be spotted using binoculars, as it
currently sweeps through the familiar constellation of Orion.
This telephoto field from November 8,
blends exposures registered on the comet with exposures
registered on Orion's stars.
It creates an effectively deep skyview that shows colors and details you
can't quite see though, even in binoculars.
The comet's telltale greenish coma is toward the upper left, above
Orion's three belt stars lined-up across the frame below center.
You'll also probably spot the Orion Nebula, and famous Horsehead Nebula
in the stunning field of view.
Of course one of
Orion's belt stars is nearly 2,000 light-years away.
On November 14,
this comet ATLAS
will fly a mere 2.9 light-minutes from Earth.
APOD: 2020 November 5 - North of Orion's Belt
Explanation:
Bright stars, interstellar clouds of dust and glowing nebulae fill
this cosmic scene,
a skyscape just north of Orion's belt.
Close to the plane of our
Milky Way Galaxy,
the wide field view spans just under 5 degrees or about 10 full moons on
the sky.
Striking
bluish M78,
a reflection nebula, is at the lower right.
M78's tint is due to dust preferentially reflecting the
blue light of hot, young stars.
In colorful contrast, the red swath of glowing hydrogen gas
streaming through the center is part of the region's faint but
extensive emission nebula
known as Barnard's Loop.
At upper left, a dark dust cloud forms a prominent silhouette
cataloged as LDN 1622.
While M78 and the complex Barnard's Loop are some 1,500 light-years
away, LDN 1622 is likely to be much closer, only about 500
light-years distant from our fair planet Earth.
APOD: 2020 October 4 - Orion Nebula in Oxygen, Hydrogen, and Sulfur
Explanation:
Few astronomical sights excite the imagination like the
nearby stellar nursery known as the Orion Nebula.
The Nebula's glowing gas
surrounds hot young stars at the edge of an immense interstellar
molecular cloud.
Many of the filamentary structures visible in the featured image are actually
shock waves -
fronts where fast moving material encounters slow moving gas.
The Orion Nebula spans about 40
light years
and is located about 1500 light years away in the
same spiral arm
of our Galaxy as the
Sun.
The Great Nebula in
Orion can be found with the
unaided eye just below and to the left of the easily identifiable
belt of three stars in the popular constellation Orion.
The image shows the nebula in
three colors
specifically emitted by
hydrogen,
oxygen, and
sulfur gas.
The whole Orion Nebula cloud complex,
which includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: 2020 September 19 - Orion in Depth
Explanation:
Orion is a familiar constellation.
The apparent positions of its stars in two dimensions
create a well-known pattern
on the bowl
of planet Earth's night sky.
Orion may
not look quite so familiar in this 3D view though.
The illustration reconstructs
the relative positions of Orion's
bright stars, including data from the
Hipparcus catalog of
parallax
distances.
The most distant star shown is Alnilam.
The middle one in the projected line of three that make up Orion's
belt when viewed from planet Earth, Alnilam is nearly 2,000 light-years
away, almost 3 times as far as
fellow belt stars Alnitak and Mintaka.
Though Rigel and Betelgeuse apparently shine brighter in planet Earth's sky,
that makes more distant Alnilam intrinsically (in absolute magnitude)
the brightest of the familiar stars in Orion.
In the Hipparcus catalog, errors in measured parallaxes for Orion's stars
can translate in to distance errors of a 100 light-years
or so.
APOD: 2020 August 28 - The Valley of Orion
Explanation:
This exciting and unfamiliar view
of the Orion Nebula is a visualization based on
astronomical data
and movie rendering techniques.
Up close and personal with a famous stellar nursery
normally seen
from 1,500 light-years away, the digitally modeled
frame transitions from a visible light representation based on
Hubble data on the left to infrared data from the
Spitzer Space Telescope on the right.
The perspective at the center looks along a valley over a
light-year wide, in the wall of the region's giant molecular cloud.
Orion's valley ends in a cavity carved by the energetic winds
and radiation of the massive central stars of the
Trapezium star cluster.
The single frame is part of a multiwavelength, three-dimensional video
that lets the viewer experience an immersive,
three
minute flight through the Great Nebula of Orion.
APOD: 2020 July 6 - M43: Dust, Gas, and Stars in the Orion Nebula
Explanation:
Unspeakable beauty and unimaginable bedlam can be found together in the Orion Nebula
Arguably the most famous of all astronomy nebulas, the
Great Nebula in Orion is an
immense interstellar
molecular cloud only 1500
light-years away.
In the featured deep image shown in assigned colors, the
part of the nebula's center known as M43 is shown as taken by the
Hubble Space Telescope.
The Great Nebula in Orion can be found with the
unaided eye near the
easily identifiable
belt of three stars in the popular constellation
Orion.
The entire Orion Nebula, including both
M42 and
M43 spans about 40
light years and is located in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2020 June 9 - Orion over Argentine Mountains
Explanation:
Do you recognize the constellation of Orion?
It may be harder than usual in today's
featured image
because the camera has zoomed in on the center,
and the exposure is long enough to enhance
nebulas beyond what the unaided
human eye can see.
Still, once you become oriented, you can see
Orion's three belt stars
lined up vertically near the image center, and even locate the
familiar Orion Nebula on the upper left.
Famous faint features that are also visible include the dark
Horsehead Nebula indentation near the image center,
and the dusty
Flame Nebula just to its right.
Part of the
Orion-encircling
Barnard's Loop can also be found on the far right.
The image combines multiple
sky-tracking shots of the background in different colors
with a single static foreground exposure taken at twilight -- all
captured
with the same camera and from the same location.
The picturesque scene was captured early last year from mountains in
San Juan,
Argentina.
APOD: 2020 March 29 - A 212 Hour Exposure of Orion
Explanation:
The constellation of Orion is much more than three stars in a row.
It is a direction in space that is
rich with impressive nebulas.
To better appreciate this well-known swath of sky, an
extremely long exposure was taken over many clear nights in 2013 and 2014.
After 212 hours of camera time and an
additional year of processing, the featured 1400-exposure collage spanning over 40 times the
angular diameter of
the Moon emerged.
Of the many interesting details that have become visible, one that particularly draws the eye is
Barnard's Loop, the bright red circular filament arcing down from the middle.
The Rosette Nebula is not the giant red nebula near the top of the image -- that is a larger but lesser known nebula known as Lambda Orionis.
The Rosette Nebula is visible, though: it is the red and white nebula on the upper left.
The bright orange star just above the frame center is
Betelgeuse, while the bright blue star on the lower right is
Rigel.
Other famous nebulas visible include
the Witch Head Nebula,
the Flame Nebula,
the Fox Fur Nebula, and, if you know just where to look,
the comparatively small Horsehead Nebula.
About those
famous three stars that cross the belt of
Orion the Hunter --
in this busy frame they can be hard to locate, but a
discerning eye will find them just below and to the right of the image center.
APOD: 2020 February 21 - LDN 1622: Dark Nebula in Orion
Explanation:
The silhouette of an intriguing
dark nebula
inhabits this cosmic scene.
Lynds' Dark Nebula
(LDN) 1622 appears against a faint
background of glowing hydrogen gas only visible in long telescopic
exposures of the region.
In contrast, the brighter reflection nebula
vdB 62 is more easily
seen, just above and right of center.
LDN 1622 lies near the plane of our Milky Way Galaxy,
close on the sky to
Barnard's
Loop,
a large cloud surrounding the rich
complex of emission nebulae found
in the Belt and Sword
of Orion.
With swept-back outlines, the obscuring dust of LDN 1622 is thought
to lie at a similar distance, perhaps 1,500 light-years away.
At that distance, this 1 degree wide field of view
would span about 30 light-years.
Young
stars do lie hidden within the dark expanse and have been
revealed in Spitzer Space telescope
infrared images.
Still, the foreboding visual appearance of LDN 1622
inspires its popular name,
the Boogeyman Nebula.
APOD: 2020 February 18 - Orion over the Central Bohemian Highlands
Explanation:
Do you recognize this constellation?
Setting past the
Central Bohemian Highlands in the
Czech Republic
is Orion, one of the most identifiable
star groupings on the sky and an icon familiar to
humanity for over 30,000 years.
Orion has looked pretty much the same during this time and should continue to look the same for many thousands of years into the future.
Prominent
Orion is high in the sky at sunset this time of year, a recurring sign of (modern) winter in
Earth's
northern hemisphere and summer in the south.
The featured picture is a composite of over thirty images taken from the
same location
and during the same night last month.
Below and slightly to the left of
Orion's three-star belt is the
Orion Nebula,
while four of the bright stars surrounding the belt are, clockwise,
Sirius (far left, blue),
Betelgeuse (top, orange,
unusually faint),
Aldebaran (far right), and Rigel (below).
As future weeks progress,
Orion will set increasingly earlier.
APOD: 2020 January 20 - Quadrantid Meteors through Orion
Explanation:
Why are these meteor trails nearly
parallel?
Because they were all shed by the
same space rock and so can be
traced back to the same direction on the sky: the
radiant of the
Quadrantid Meteor Shower.
This direction used to be toward the old constellation of
Quadrans Muralis,
hence the name Quadrantids, but when the
International Astronomical Union formulated its
list of modern constellations in 1922,
this constellation
did not make the list.
Even though the
meteors are now considered
to originate from the recognized
constellation of Bootes,
the old name stuck.
Regardless of the designation, every January the Earth moves through a
dust stream and bits of this
dust glow as meteors as they heat up in
Earth's atmosphere.
The featured image composite was taken on January 4 with a picturesque snowy
Slovakian
landscape in the foreground, and a
deep-exposure sky prominently featuring the constellation Orion in the background.
The red star
Betelgeuse
appears unusually dim --
its fading over the past few months is being
tracked by astronomers.
APOD: 2019 November 22 - Orion Rising
Explanation:
Looking toward
the east in the early hours of a
September morning this single exposure made with tripod and camera
captured a simple visual experience.
Rising above the tree-lined slope are familiar stars
in planet Earth's northern night and the
constellation Orion the Hunter.
Brighter stars marking the celestial Hunter's
shoulder (Betelgeuse), foot (Rigel), belt, and sword
are clearly reflected in the calm waters from northern
Latvia's Vitrupe river.
Of course,
winter is coming
to planet Earth's northern hemisphere.
By then Orion and this beautiful starry vista will
be seen
rising in early evening skies.
APOD: 2019 October 30 - M42: Inside the Orion Nebula
Explanation:
The Great Nebula in Orion,
an immense, nearby
starbirth region,
is probably the most famous of all
astronomical nebulas.
Here, glowing gas
surrounds hot young stars at the edge of an
immense interstellar
molecular cloud only 1500
light-years away.
In the featured deep image in
assigned colors highlighted by
emission in
oxygen and
hydrogen,
wisps and sheets of dust and gas are particularly evident.
The Great Nebula in Orion
can be found with the unaided eye near the
easily identifiable
belt of three stars in the popular constellation
Orion.
In addition to housing a bright
open cluster of stars known as the
Trapezium, the
Orion Nebula contains many stellar nurseries.
These nurseries contain much
hydrogen gas,
hot young stars,
proplyds, and
stellar jets
spewing material at high speeds.
Also known as
M42, the
Orion Nebula spans about 40 light years and is located in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2019 September 30 - Orion Rising over Brazil
Explanation:
Have you seen Orion lately?
The next few months will be the best for seeing this familiar constellation as it rises continually earlier in the night.
However, Orion's stars and
nebulas won't look
quite as colorful to the eye as they do in this
fantastic camera image.
In the featured image,
Orion
was captured by camera showing its full colors last month
over a Brazilian copal tree from
Brazil's
Central-West Region.
Here the cool red giant
Betelgeuse
takes on a strong orange hue as the brightest star on the far left.
Otherwise, Orion's hot blue
stars are numerous, with
supergiant Rigel
balancing Betelgeuse at the upper right, Bellatrix at the upper left, and
Saiph at the lower right.
Lined up in Orion's belt (bottom to top) are
Alnitak, Alnilam, and Mintaka
all about 1,500
light-years away, born of the constellation's well studied
interstellar clouds.
And if a "star" toward the upper right
Orion's sword
looks reddish and fuzzy to you, it should.
It's the stellar nursery known as the
Great Nebula of Orion.
APOD: 2019 August 31 - Spitzer's Orion
Explanation:
Few cosmic vistas excite the imagination like
the Orion Nebula,
an immense stellar nursery some 1,500 light-years away.
Spanning about 40 light-years across the region,
this infrared image
from the Spitzer Space Telescope was constructed from data intended to
monitor
the brightness of the nebula's young stars, many still surrounded
by dusty, planet-forming disks.
Orion's young stars are only about 1 million years old,
compared to the Sun's age of 4.6 billion years.
The region's hottest stars are found in the
Trapezium Cluster, the brightest cluster
near picture center.
Launched into orbit around the Sun
on August 25, 2003 Spitzer's liquid helium
coolant ran out in May 2009.
The infrared space telescope continues to operate though, its mission
scheduled to end on January 30, 2020.
Recorded in 2010, this false color view is from two
channels that still remain sensitive to
infrared light
at Spitzer's warmer operating temperatures.
APOD: 2019 August 21 - The Orion You Can Almost See
Explanation:
Do you recognize this constellation?
Although it is one of the
most recognizable star groupings on the sky,
this is a
more full Orion than you can see --
an Orion only revealed with long exposure digital
camera imaging and
post-processing.
Here the cool
red giant
Betelgeuse
takes on a strong orange tint as the brightest star at the lower left.
Orion's hot blue stars are numerous, with
supergiant
Rigel balancing Betelgeuse on the upper right, and
Bellatrix at the upper left.
Lined up in
Orion's belt are three stars
all about 1,500
light-years away, born from the constellation's well-studied
interstellar clouds.
To the right of Orion's belt is a bright but fuzzy patch that might also
look familiar -- the stellar nursery known as
Orion's Nebula.
Finally, just barely visible to the
unaided eye but quite striking here is
Barnard's Loop -- a huge gaseous emission nebula surrounding Orion's Belt and Nebula discovered over 100 years ago by the pioneering Orion photographer
E. E. Barnard.
APOD: 2019 August 17 - 1901 Photograph: The Orion Nebula
Explanation:
By the turn of the 20th century advances in photography
contributed an important
tool for astronomers.
Improving photographic materials,
long exposures, and new telescope designs produced astronomical
images with details not visible at
the
telescopic eyepiece alone.
Remarkably
recognizable to astrophotographers today,
this stunning image of the star forming Orion Nebula was captured in
1901 by American astronomer and telescope designer
George Ritchey.
The original glass photographic plate, sensitive to green and blue
wavelengths, has been digitized and light-to-dark inverted
to produce a positive image.
His hand written notes indicate a 50 minute long exposure that ended at
dawn and a reflecting telescope
aperture of 24 inches
masked to 18 inches to improve the sharpness of the recorded image.
Ritchey's plates from over a
hundred years ago preserve astronomical data and can still be used for
exploring astrophysical processes.
APOD: 2019 June 5 - The Interstellar Clouds of Orion
Explanation:
The constellation of Orion is much more than three stars in a row.
It is a direction in space that is
rich with impressive nebulas.
To better appreciate this well-known swath of sky, a new
long exposure image
was taken over several clear nights in January, February and March.
After 23 hours of camera time and
untold hours of image processing, the featured collage in the light of
hydrogen,
oxygen, and
sulfur
was produced spanning over 40 times the
angular diameter of
the Moon.
Of the many interesting details that have become visible,
one that particularly draws the eye is
Barnard's Loop,
the bright red orange arc just to the right of the image center.
The Rosette Nebula is not the giant orange nebula just to the left of the image center -- that is larger but lesser known nebula known as the
Meissa Ring.
The Rosette Nebula is visible, though: it is the bright orange, blue and white nebula near the image bottom.
The bright orange star just left of the frame center is
Betelgeuse,
while the bright blue star on the upper right is
Rigel.
About those
famous three stars that cross the belt of
Orion the Hunter --
in this busy frame they can be hard to locate, but a
discerning eye
will find them just to the right of the image center.
APOD: 2019 March 18 - Horsehead and Orion Nebulas
Explanation:
The dark Horsehead Nebula and the glowing
Orion Nebula are contrasting cosmic vistas.
Adrift 1,500
light-years
away in one of the night sky's
most recognizable
constellations,
they appear in opposite corners of the above
stunning two-panel mosaic.
The familiar Horsehead
nebula appears as a dark cloud on the lower left, a small
silhouette
notched against the glow of hydrogen
(alpha) gas,
here tinted orange.
Alnitak is the easternmost star in
Orion's belt and can be found
to the left of the
Horsehead.
Below Alnitak is the
Flame Nebula, with clouds of
bright emission and
dramatic dark dust lanes.
The magnificent emission region, the
Orion Nebula (aka M42), lies at the upper right,
surrounded by the blue glow of reflecting dust.
Immediately to its left is a prominent
reflection nebula sometimes called the Running Man.
Pervasive tendrils
of glowing hydrogen gas are easily
traced
throughout the region.
APOD: 2019 March 3 - The Orion Bullets
Explanation:
Why are bullets of gas shooting out of the Orion Nebula?
Nobody is yet sure.
First discovered in 1983, each bullet is actually about the size of
our Solar System, and
moving at about 400 km/sec from a central source dubbed IRc2.
The age of the bullets, which can be found from their speed and distance from
IRc2,
is very young -- typically less than 1,000 years.
As the
bullets expand out the top of the
Kleinmann-Low section of the
Orion Nebula,
a small percentage of iron gas causes the
tip of each bullet to glow blue, while
each bullet leaves a tubular pillar
that glows by the light of heated hydrogen gas.
The detailed image
was created using the 8.1 meter
Gemini South telescope in
Chile with an
adaptive optics system (GeMS).
GeMS uses
five laser generated guide stars
to help compensate for the
blurring effects of planet
Earth's atmosphere.
APOD: 2019 February 27 - Magnetic Orion
Explanation:
Can magnetism affect how stars form?
Recent analysis of Orion data from the
HAWC+ instrument on the airborne
SOFIA observatory
indicate that, at times, it can.
HAWC+ is able to measure the
polarization of far-infrared light which can reveal the alignment of
dust grains by expansive ambient
magnetic fields.
In the
featured image,
these magnetic fields are shown as curvy lines superposed on an
infrared image of the
Orion Nebula taken by a
Very Large
Telescope in
Chile.
Orion's
Kleinmann-Low Nebula is visible slightly to the upper right of the image center, while bright stars of the
Trapezium cluster
are visible just to the lower left of center.
The Orion Nebula at about l300
light years distant is the nearest major
star formation region to the
Sun.
APOD: 2019 February 2 - LDN 1622: Dark Nebula in Orion
Explanation:
The silhouette of an intriguing
dark nebula
inhabits this cosmic scene.
Lynds' Dark Nebula
(LDN) 1622 appears against a faint
background of glowing hydrogen gas only easily seen in long telescopic
exposures of the region.
LDN 1622 lies near the plane of our Milky Way Galaxy,
close on the sky to
Barnard's
Loop,
a large cloud surrounding the rich
complex of emission nebulae found
in the Belt and Sword
of Orion.
But the obscuring dust of LDN 1622 is thought to be much closer
than Orion's more famous nebulae, perhaps only 500 light-years away.
At that distance, this 1 degree wide field of view
would span less than 10 light-years.
Its foreboding appearance lends this dark expanse a popular name,
the Boogeyman Nebula.
APOD: 2019 January 23 - Orion over the Austrian Alps
Explanation:
Do you recognize this constellation?
Through the icicles and past the mountains is
Orion, one of the most identifiable star groupings on the sky and an icon familiar to humanity for over 30,000 years.
Orion has
looked pretty much the same during the past 50,000 years and should continue to look the same for many thousands of years into the future.
Orion is quite prominent in the sky this time of year, a recurring sign of (modern) winter in Earth's northern hemisphere and summer in the south.
Pictured, Orion was captured recently above the
Austrian
Alps in a composite of seven images taken by the same camera in the same location during the same night.
Below and slightly to the right of
Orion's three-star belt is the
Orion Nebula,
while the four bright stars surrounding the belt are, clockwise from the upper left,
Betelgeuse,
Bellatrix,
Rigel, and
Saiph.
APOD: 2019 January 2 - The Orion Nebula in Infrared from WISE
Explanation:
The Great Nebula in Orion is an intriguing place.
Visible to the unaided eye, it appears as a small
fuzzy patch in the
constellation of Orion.
But
this image,
an illusory-color four-panel mosaic taken in different bands of
infrared light with the
Earth orbiting
WISE observatory, shows the
Orion Nebula
to be a bustling
neighborhood of recently formed stars,
hot gas, and dark dust.
The power behind much of the
Orion Nebula (M42) is the stars of the
Trapezium star cluster, seen
near the center of the
featured image.
The orange glow surrounding the
bright stars pictured here is their own
starlight reflected
by intricate dust filaments that
cover much of the region.
The current
Orion Nebula cloud complex, which
includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: 2018 December 12 - M43: Orion Falls
Explanation:
Is there a waterfall in Orion?
No, but some of the dust in M43 appears similar to a
waterfall on Earth.
M43, part of the
Orion Molecular Cloud
Complex, is the often imaged but rarely mentioned neighbor
of the more famous M42.
M42, which includes many bright stars from the
Trapezium cluster, lies above the featured scene.
M43
is itself a star forming region and although laced with filaments of dark dust,
is composed mostly of glowing
hydrogen.
The entire
Orion field, located about 1600
light years away, is inundated with many intricate and
picturesque
filaments of dust.
Opaque to visible light, dark
dust is
created in the outer atmosphere of massive cool stars and expelled by a strong
outer wind of
protons and
electrons.
APOD: 2018 November 30 - A Cold River to Orion
Explanation:
Ice
is forming on the river Lielupe as it flows through the
landscape
in this winter's night scene.
Even in motion the frigid water still reflects a starry sky, though.
The well planned,
Orion-centered
panorama looks toward the south,
taken in three exposures from a bridge near the
village of Stalgene, Latvia,
planet
Earth.
Drifting pancakes of ice leave streaks in the long exposures,
while familiar stars of Orion and the northern winter night
appear above and below the horizon.
Village lights along the horizon include skyward beams from the
local community church.
This image was a first place winner in the 2018 StarSpace
astrophotography competition.
APOD: 2018 October 14 - Orion in Red and Blue
Explanation:
When did Orion become so flashy?
This colorful rendition of part of the
constellation of Orion comes from red light emitted by
hydrogen and
sulfur
(SII), and blue-green light emitted by
oxygen
(OIII).
Hues on the
featured image
were then digitally reassigned to be indicative of their
elemental origins -- but also striking to the
human eye.
The breathtaking composite was
painstakingly composed from
hundreds of images which took nearly 200 hours to collect.
Pictured, Barnard's Loop, across the image bottom,
appears to cradle interstellar constructs including the intricate
Orion Nebula seen just right of center.
The Flame Nebula can also be quickly located,
but it takes a careful eye to identify the slight indentation of the dark
Horsehead Nebula.
As to Orion's flashiness -- a leading explanation for the origin of
Barnard's Loop is a
supernova blast that occurred about two million years ago.
APOD: 2018 August 5 - Trapezium: At the Heart of Orion
Explanation:
Near the center of this sharp cosmic portrait, at
the heart of the Orion Nebula,
are four hot, massive stars
known as
the Trapezium.
Gathered within a region about 1.5 light-years in radius,
they dominate the core of the dense Orion Nebula Star Cluster.
Ultraviolet ionizing radiation from the
Trapezium stars,
mostly from the brightest star
Theta-1
Orionis C
powers the complex star forming region's entire visible glow.
About three million years old, the Orion Nebula Cluster was
even more compact in its younger years and a
recent dynamical study indicates that
runaway stellar collisions
at an earlier age may have formed a black hole
with more than 100 times the mass of
the Sun.
The presence of a
black hole within the cluster
could explain the observed high velocities of the
Trapezium stars.
The Orion Nebula's distance of some 1,500
light-years would make it the
closest known black hole to planet Earth.
APOD: 2018 March 21 - Camera Orion
Explanation:
Do you recognize this constellation?
Although it is one of the
most recognizable star groupings on the sky, Orion's icons
don't look quite as colorful to the eye as they do to a camera.
In this 20-image digitally-composed mosaic, cool
red giant
Betelgeuse
takes on a strong orange tint as the brightest star at the upper left.
Orion's hot blue stars are numerous, with
supergiant
Rigel balancing Betelgeuse at the lower right, and
Bellatrix at the upper right
Lined up in
Orion's belt are three stars
all about 1,500
light-years away, born from the constellation's well-studied
interstellar clouds.
Below Orion's belt a reddish and fuzzy patch that might also
look familiar -- the stellar nursery known as
Orion's Nebula.
Finally, just barely visible to the unaided eye but quite striking here by camera is
Barnard's Loop -- a huge gaseous emission nebula surrounding Orion's Belt and Nebula discovered over 100 years ago by the pioneering Orion photographer
E. E. Barnard.
APOD: 2018 February 18 - LL Ori and the Orion Nebula
Explanation:
Stars can make waves in the Orion Nebula's sea of gas and dust.
This esthetic close-up
of cosmic clouds and stellar winds
features LL Orionis, interacting with the
Orion Nebula flow.
Adrift in Orion's
stellar nursery
and still in its formative years, variable star
LL Orionis produces a wind more energetic than
the wind from our own
middle-aged Sun.
As the fast stellar wind runs into slow moving gas a shock front is
formed, analogous to the
bow
wave of a boat moving through water or
a plane traveling at supersonic speed.
The small, arcing, graceful structure just above and left of
center is LL Ori's cosmic
bow shock, measuring about half a light-year across.
The slower gas is flowing away from the
Orion Nebula's hot central star
cluster, the Trapezium, located off the upper left corner
of the picture.
In three dimensions,
LL Ori's wrap-around shock front is shaped like a
bowl that appears brightest when viewed along the "bottom" edge.
This beautiful painting-like photograph
is part of a
large mosaic view of
the complex
stellar nursery in Orion, filled with a myriad of
fluid
shapes associated with
star formation.
APOD: 2018 January 17 - In the Valley of Orion
Explanation:
This exciting and unfamiliar view
of the Orion Nebula is a visualization based on
astronomical data
and movie rendering techniques.
Up close and personal with a famous stellar nursery
normally seen
from 1,500 light-years away, the digitally modeled
frame transitions from a visible light representation based on
Hubble data on the left to infrared data from the
Spitzer Space Telescope on the right.
The perspective at the center looks along a valley over a
light-year wide, in the wall of the region's giant molecular cloud.
Orion's valley ends in a cavity carved by the energetic winds
and radiation of the massive central stars of the
Trapezium star cluster.
The single frame is part of a multiwavelength, three-dimensional video
that lets the viewer experience an immersive,
three
minute flight through the Great Nebula of Orion.
APOD: 2017 November 29 - M42: The Great Orion Nebula
Explanation:
Few astronomical sights excite the imagination like the
nearby stellar nursery known as the Orion Nebula.
The Nebula's glowing gas
surrounds hot young stars at the edge of an immense interstellar
molecular cloud.
Many of the filamentary structures visible in the
featured image are actually
shock waves -
fronts where fast moving material encounters slow moving gas.
The Orion Nebula spans about 40
light years
and is located about 1500 light years away in the
same spiral arm
of our Galaxy as the
Sun.
The Great Nebula in
Orion can be found with the
unaided eye just below and to the left of the easily identifiable
belt of three stars in the popular
constellation Orion.
The featured image,
taken last month, shows a two-hour exposure of the nebula in three colors.
The whole Orion Nebula cloud complex,
which includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: 2017 October 30 - Orionid Meteors from Orion
Explanation:
Meteors have been shooting out from the constellation of Orion.
This was expected, as October is the time of year for the
Orionids Meteor Shower.
Pictured here, over a dozen meteors were caught in successively
added exposures last weekend over
Wulan Hada volcano in
Inner Mongolia,
China.
The featured image shows
multiple meteor streaks
that can all be connected to a single small region on the sky called the
radiant,
here visible just above and to the left of the
belt of Orion,
The Orionids
meteors started as sand sized bits expelled from
Comet Halley
during one of its trips to the inner
Solar System.
Comet Halley is
actually responsible for two
known meteor showers,
the other known as the
Eta Aquarids and
visible every May.
Next month, the
Leonids Meteor Shower
from Comet Tempel-Tuttle should also result in
some bright meteor streaks.
APOD: 2017 September 18 - Orion above Easter Island
Explanation:
Why were the statues on
Easter Island built?
No one is sure.
What is sure is that over 800 large stone statues exist there.
The Easter Island statues, stand, on the average, over
twice as tall as a person and have over 200 times as much mass.
Few specifics are known about the history or meaning of the
unusual rock sculptures,
but many believe that they were created about 700 years ago in the
images
of local leaders of a lost civilization.
Featured here, one of the ancient
Moai sculptures
was imaged in 2016 before
the constellation of Orion, including the famous line of
three belt stars and brilliant stars
Betelgeuse (far left in red) and
Rigel (upper center).
The stone
giant appears, however, to be
inspecting the brightest star in the night sky (far right):
Sirius.
APOD: 2017 June 4 - Orion: Belt, Flame, and Horsehead
Explanation:
What surrounds the famous belt stars of Orion?
A deep exposure shows everything from dark nebula to star clusters,
all embedded in an extended
patch of
gaseous wisps in the greater
Orion
Molecular
Cloud
Complex.
The brightest three stars,
appearing diagonally on the left of the featured image are indeed the
famous three stars that make up the
belt of Orion.
Just below Alnitak, the lowest of the
three belt stars, is the
Flame Nebula, glowing with
excited hydrogen gas and immersed in filaments of dark brown dust.
Just to the right of
Alnitak lies the
Horsehead Nebula, a
dark indentation of
dense dust that has perhaps the most recognized nebular shapes on the sky.
The dark molecular cloud, roughly 1,500
light years distant, is cataloged as Barnard 33 and is seen primarily because it is backlit by the nearby massive star
Sigma Orionis.
The Horsehead Nebula will slowly shift its
apparent shape over the next few million years and will eventually be destroyed by the
high-energy starlight.
APOD: 2017 March 21 - Fast Stars and Rogue Planets in the Orion Nebula
Explanation:
Start with the constellation of Orion.
Below Orion's belt
is a fuzzy area known as the Great Nebula of Orion.
In this nebula is a bright star cluster known as the
Trapezium,
marked by four bright stars near the image center.
The newly born stars in the
Trapezium and
surrounding regions show the
Orion Nebula
to be one of the most active areas of star formation to be found in our area of
the Galaxy.
In Orion,
supernova explosions and close interactions between stars have created
rogue planets and stars that rapidly move through space.
Some of these
fast stars have been found by
comparing different images
of this region taken by the
Hubble Space Telescope many years apart.
Many of the stars in the
featured image, taken in visible and near-infrared light, appear
unusually red
because they are seen through
dust that scatters away much of their blue light.
APOD: 2017 March 12 - At the Heart of Orion
Explanation:
Near the center of this sharp cosmic portrait, at the heart of
the
Orion Nebula, are four hot, massive stars
known as
the Trapezium.
Tightly gathered within a region
about 1.5 light-years in radius,
they dominate the core of the dense Orion Nebula Star Cluster.
Ultraviolet ionizing radiation from the Trapezium stars,
mostly from the brightest star
Theta-1
Orionis C
powers the complex star forming region's entire visible glow.
About three million years old, the Orion Nebula Cluster was
even more compact in its younger years and a
dynamical study
indicates that
runaway stellar collisions
at an earlier age may have formed a black hole
with more than 100 times the mass of the Sun.
The presence of a black hole within the cluster
could explain the observed high velocities of the Trapezium stars.
The Orion Nebula's distance of some 1,500 light-years
would make it the closest known black hole to planet Earth.
APOD: 2017 March 8 - Dust, Gas, and Stars in the Orion Nebula
Explanation:
The Great Nebula in Orion,
an immense, nearby
starbirth region,
is probably the most famous of all
astronomical nebulas.
Here, filaments of dark dust and glowing gas
surround hot young stars at the edge of an
immense interstellar
molecular cloud only 1500
light-years away.
In the featured deep image shown in assigned colors,
part of the nebula's center is shown as taken by the
Hubble Space Telescope.
The Great Nebula in Orion can be found with the
unaided eye near the
easily identifiable
belt of three stars in the popular constellation
Orion.
In addition to housing a bright
open cluster of stars known as the
Trapezium, the
Orion Nebula contains many
stellar nurseries.
These nurseries contain much
hydrogen gas, hot young stars,
proplyds, and
stellar jets
spewing material at high speeds.
Also known as
M42 and
M43, the
Orion Nebula spans about 40
light years and is located in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2017 January 24 - M78 and Orion Dust Reflections
Explanation:
In the vast Orion Molecular Cloud complex,
several bright blue nebulas are particularly apparent.
Pictured here are two of the most prominent
reflection nebulas -
dust clouds lit by the
reflecting light of bright embedded
stars.
The more famous nebula is
M78,
in the image center, cataloged over 200 years ago.
To its left is the lesser known
NGC 2071.
Astronomers continue to
study these
reflection nebulas to
better understand how interior stars form.
The Orion complex
lies about 1500 light-years distant, contains the
Orion and
Horsehead nebulas,
and covers much of the
constellation of Orion.
APOD: 2017 January 16 - Geostationary Highway through Orion
Explanation:
Put a satellite
in a circular orbit about 42,000 kilometers from the
center of the Earth and it will orbit once in 24 hours.
Because that matches Earth's rotation period, it is known as a
geosynchronous orbit.
If that orbit is also in the plane of the equator,
the satellite will hang in the sky over a fixed location in
a
geostationary orbit.
As predicted in the 1940s by futurist
Arthur
C. Clarke, geostationary
orbits are in common use
for communication and weather satellites,
a scenario now well-known to astroimagers.
Deep images of the night sky made with telescopes that follow
the stars can also
pick up geostationary
satellites glinting in sunlight still shining
far above the Earth's surface.
Because they all move with the
Earth's rotation against the
background of stars, the satellites leave trails that
seem to follow a highway across the celestial landscape.
The phenomenon was captured last month in this video showing
several satellites
in geostationary orbit crossing the famous
Orion Nebula.
APOD: 2016 December 4 - Official Star Names for Orion
Explanation:
Familiar stars in Orion and constellations across the sky now have official names.
Over the past year, the
International Astronomical Union, the
only
body officially tasked with naming stars,
approved names already in common use for
227 of the brightest stars, including the most famous stars on the sky
Sirius,
Polaris, and
Betelgeuse.
Pictured, the
constellation of Orion is shown with several of these
now-official star names superposed.
Spanning about 30 degrees,
this breath-taking vista
stretches across the well-known constellation from
head to toe (left to right) and beyond.
The common names for all three stars in Orion's belt
are also now official.
At 1,500 light years away, the Great Orion
Nebula is the closest large star forming region, here visible
just right and below center.
Also visible are famous nebulae including the
Horsehead Nebula and the
Witch Head Nebula.
Of course, the Orion Nebula and bright stars are
easy to see with the
unaided eye, but dust clouds and emission from the extensive interstellar
gas in this nebula-rich complex,
are too faint and much harder to record.
In the
featured mosaic of broadband telescopic images, additional image
data acquired with a narrow
hydrogen alpha filter was used to
bring out the pervasive tendrils of energized
atomic hydrogen gas like in the arc of the giant
Barnard's Loop.
APOD: 2016 October 14 - Herschel's Orion
Explanation:
This
dramatic image peers within M42, the Orion Nebula,
the closest large star-forming region.
Using data at infrared wavelengths from the
Herschel
Space Observatory, the false-color composite
explores the natal cosmic cloud
a mere 1,500 light-years distant.
Cold, dense filaments
of dust that
would otherwise be dark at visible wavelengths are shown
in reddish hues.
Light-years long, the filaments weave together
bright spots that correspond to regions of collapsing
protostars.
The brightest bluish area near the top of the frame is warmer
dust heated by the hot Trapezium
cluster stars that also power the nebula's visible glow.
Herschel data has recently indicated
ultraviolet starlight from the hot newborn stars
likely contributes to the creation of
carbon-hydrogen molecules,
basic
building blocks of life.
This Herschel image spans about 3 degrees on the sky.
That's about 80 light-years at the distance of the Orion Nebula.
APOD: 2016 July 18 - The Orion Nebula in Infrared from HAWK I
Explanation:
The deepest infrared image of the Orion Nebula has uncovered a bonanza of previously unknown low-mass stars and -- quite possibly -- free floating planets.
The picturesque
nebula is best known in
visible light where it shows a many
bright stars and bright glowing gas.
Catalogued as
M42, the
Orion
Nebula at a distance of 1300
light years is the closest major star forming region to Earth.
One can
peer into Orion's pervasive dust
in
infrared light, as was done again recently with the sophisticated
HAWK-I camera attached to one of the
European Southern Observatory's
Very Large Telescopes
in the high mountains of
Chile.
High resolution versions of the
featured infrared deep image show many points of light, many of which are surely
brown dwarf stars but some of which are best fit by an unexpectedly high abundance of
free-floating planets.
Understanding
how these low mass objects formed is important to
understanding
star formation generally and may even help humanity to better understand the early years of our Solar System.
APOD: 2016 May 17 - The Orion Nebula in Visible and Infrared
Explanation:
The Great Nebula in Orion is a colorful place.
Visible to the unaided eye, it appears as a small
fuzzy patch in the constellation of Orion.
Long exposure,
multi-wavelength images like this, however, show the
Orion Nebula to be a busy neighborhood of young stars, hot gas, and dark
dust.
This digital composite
features not only three colors of
visible light but four colors of
infrared light taken by
NASA's orbiting
Spitzer Space Telescope as well.
The power behind much of the
Orion Nebula
(M42) is the
Trapezium -
four of the brightest stars in the nebula.
Many of the
filamentary structures visible are actually
shock waves - fronts
where fast moving material encounters slow moving gas.
The Orion Nebula spans about 40 light years and is
located about 1500
light years away in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2016 April 13 - Orion in Red and Blue
Explanation:
When did Orion become so flashy?
This colorful rendition of part of the
constellation of Orion comes from red light emitted by
hydrogen and
sulfur
(SII), and blue-green light emitted by
oxygen
(OIII).
Hues on the
featured image
were then digitally reassigned to be indicative of their
elemental origins -- but also striking to the
human eye.
The breathtaking composite was
painstakingly composed from
hundreds of images which took nearly 200 hours to collect.
Pictured, Barnard's Loop, across the image bottom,
appears to cradle interstellar constructs including the intricate
Orion Nebula seen just right of center.
The Flame Nebula can also be quickly located,
but it takes a careful eye to identify the slight indentation of the dark
Horsehead Nebula.
As to Orion's flashiness -- a leading explanation for the origin of
Barnard's Loop is a
supernova blast that occurred about two million years ago.
APOD: 2016 March 28 - Orion's Belt and Sword over Teide's Peak
Explanation:
The southern part of Orion, the famous constellation and mythical hunter, appears quite picturesque posing here over a famous volcano.
Located in the
Canary Islands off the northwest coast of Africa,
the snow-peaked
Teide is one of the largest volcanoes on Earth.
Lights from a group planning to
summit Teide before dawn are visible below the
volcano's peak.
In this composite of exposures taken from the same location one night last month, the
three iconic
belt stars of
Orion are seen just above the peak, while the famous
Orion Nebula and the rest of
Orion's sword
are visible beyond the volcano's left slope.
Also visible in the long duration sky image are the
Horsehead Nebula,
seen as a dark indentation on the red
emission nebula
to the belt's left, and the Flame Nebula,
evident just above and to the right of the Horsehead.
APOD: 2015 December 29 - Dust of the Orion Nebula
Explanation:
What surrounds a hotbed of star formation?
In the case of the
Orion Nebula -- dust.
The
entire Orion field, located about 1600
light years away, is inundated with intricate and
picturesque filaments of dust.
Opaque to visible light,
dust is created in the outer atmosphere of massive
cool stars and expelled by a strong outer
wind of particles.
The Trapezium and other forming
star clusters
are embedded in the nebula.
The intricate filaments of dust surrounding
M42 and
M43 appear brown in the
featured image, while central glowing gas is highlighted in red.
Over the next few million years much of
Orion's dust will be slowly
destroyed by the very stars now being formed, or dispersed into the
Galaxy.
APOD: 2015 November 23 - A 212 Hour Exposure of Orion
Explanation:
The constellation of Orion is much more than three stars in a row.
It is a direction in space that is
rich with impressive nebulas.
To better appreciate this well-known swath of sky, an
extremely long exposure was taken over many clear nights in 2013 and 2014.
After 212 hours of camera time and an
additional year of processing, the featured 1400-exposure collage spanning over 40 times the
angular diameter of
the Moon emerged.
Of the many interesting details that have become visible, one that particularly draws the eye is
Barnard's Loop, the bright red circular filament arcing down from the middle.
The Rosette Nebula is not the giant red nebula near the top of the image -- that is a larger but lesser known nebula known as Lambda Orionis.
The Rosette Nebula is visible, though: it is the red and white nebula on the upper left.
The bright orange star just above the frame center is
Betelgeuse, while the bright blue star on the lower right is
Rigel.
Other famous nebulas visible include
the Witch Head Nebula,
the Flame Nebula,
the Fox Fur Nebula, and, if you know just where to look,
the comparatively small Horsehead Nebula.
About those
famous three stars that cross the belt of
Orion the Hunter --
in this busy frame they can be hard to locate, but a
discerning eye will find them just below and to the right of the image center.
APOD: 2015 November 16 - A Blazing Fireball between the Orion Nebula and Rigel
Explanation:
What's happening to that meteor?
A few days ago, a bright fireball was
photographed from the
Alps mountain range in
Switzerland as it blazed across the sky.
The fireball, likely from the
Taurids meteor shower,
was notable not only for how bright it was, but for the rare orange light it created that lingered for several minutes.
Initially, the orange glow made it seem like the
meteor trail was on fire.
However, the orange glow, known as a
persistent train, originated neither from fire nor sunlight-reflecting smoke.
Rather, the persistent train's glow emanated from atoms in the
Earth's atmosphere in the path of the meteor -- atoms that had an
electron
knocked away and emit light during reacquisition.
Persistent trains often drift,
so that the long 3-minute exposure actually captured the initial
wind-blown displacement of these bright former
ions.
The featured image was acquired when trying to image the famous
Orion Nebula, visible on the upper left.
The bright blue star
Rigel, part of the
constellation of Orion, is visible to the right.
This week the
fireball-rich Taurids meteor shower continues to be active even though it has passed its peak,
while the more active
Leonids meteor shower is just peaking.
APOD: 2015 November 4 - The Great Orion Nebula M42
Explanation:
The Great Nebula
in Orion, also known as M42, is one of the
most famous nebulae in the sky.
The star forming region's glowing gas clouds and hot young stars
are on the right in this sharp and colorful image that includes the bluish reflection nebulae
NGC 1977 and friends on the left.
Located at the edge of an otherwise invisible
giant molecular
cloud complex,
these eye-catching nebulas represent only a small
fraction of this galactic neighborhood's wealth of
interstellar material.
Within the
well-studied
stellar nursery, astronomers have also
identified
what appear to be numerous infant planetary systems.
The gorgeous skyscape spans nearly two degrees or about 45
light-years
at the Orion Nebula's estimated distance of 1,500 light-years.
APOD: 2015 October 5 - Orion Over and Under Tibet
Explanation:
This night was so serene you could see Orion rise downwards.
The unusual spectacle was captured in this single-exposure image, featuring a deep sky around the famous constellation of Orion that appeared both above -- and reflected in -- a peaceful lake in the
Gyirong Valley of
Tibet,
China.
Taken last year at this time, the three belt
stars of Orion can be seen lined up almost vertically above and below the
Himalayan Mountains.
The complex Orion Nebula can be seen to the belt stars' right, while the red-glowing circular structure
surrounding Orion is Barnard's Loop.
Also, the bright red star
Betelgeuse is
doubly visible on the image left, while bright blue
Rigel appears twice on the image right.
Familiar Orion is becoming
increasingly visible
as Winter (Summer) descends on the Northern (Southern) hemisphere.
APOD: 2015 March 26 - Orion Spring
Explanation:
As spring comes to planet Earth's northern hemisphere, familiar winter
constellation Orion sets in early evening skies and budding trees
frame the Hunter's stars.
The yellowish hue of cool red supergiant
Alpha
Orionis,
the great star Betelgeuse, mingles with the branches at the top of
this
colorful skyscape.
Orion's alpha star is joined on the far right by
Alpha
Tauri.
Also known as Aldebaran and also a giant star cooler than the Sun,
it shines with a yellow light at the head of Taurus, the Bull.
Contrasting blue supergiant Rigel,
Beta
Orionis,
is Orion's other dominant star though, and marks
the Hunter's foot below center.
Of course, the sword of Orion hangs from the Hunter's three blue belt
stars near picture center, but the middle star in the sword is not a
star at all.
A slightly fuzzy pinkish glow hints at its true nature, a
nearby
stellar nursery
visible to the unaided eye known as
the Orion Nebula.
APOD: 2015 March 16 - The Clouds of Orion the Hunter
Explanation:
Cradled in cosmic dust and glowing hydrogen,
stellar
nurseries in Orion the
Hunter
lie at
the edge of giant molecular clouds some 1,500 light-years away.
Spanning about 30 degrees,
this breath-taking vista
stretches across the well-known constellation from
head to toe (left to right) and beyond.
At 1,500 light years away, the Great Orion
Nebula is the closest large star forming region, here visible
just right and below center.
To its left are the
Horsehead Nebula,
M78, and
Orion's belt stars.
Sliding your cursor over the picture will also find
red giant Betelgeuse at the hunter's shoulder,
bright blue Rigel at his foot,
the Witch Head Nebula above -- and illuminated by -- Rigel,
and the glowing Lambda Orionis
(Meissa) nebula on the left, near Orion's head.
Of course, the Orion Nebula and bright stars are
easy to see with the
unaided eye, but dust clouds and emission from the extensive interstellar
gas in this nebula-rich complex,
are too faint and much harder to record.
In this mosaic of broadband telescopic images, additional image
data acquired with a narrow
hydrogen alpha filter was used to
bring out the pervasive tendrils of energized
atomic hydrogen gas like in the arc of the giant
Barnard's Loop.
APOD: 2015 January 19 - Infrared Orion from WISE
Explanation:
The Great Nebula in Orion is an intriguing place.
Visible to the unaided eye, it appears as a small
fuzzy patch in the
constellation of Orion.
But
this image,
an illusory-color four-panel mosaic taken in different bands of
infrared light with the
Earth orbiting
WISE observatory, shows the
Orion Nebula
to be a bustling
neighborhood of recently formed stars,
hot gas, and dark dust.
The power behind much of the
Orion Nebula (M42) is the stars of the
Trapezium star cluster, seen
near the center of the
above wide field image.
The orange glow surrounding the
bright stars pictured here is their own
starlight reflected
by intricate dust filaments that
cover much of the region.
The current
Orion Nebula cloud complex, which
includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: 2015 January 2 - At the Heart of Orion
Explanation:
Near the center of this
sharp cosmic portrait, at
the heart of the
Orion Nebula, are four hot, massive stars
known as
the Trapezium.
Tightly gathered within a region about 1.5 light-years in radius,
they dominate the core of the dense Orion Nebula Star Cluster.
Ultraviolet ionizing radiation from the Trapezium stars,
mostly from the brightest star
Theta-1
Orionis C
powers the complex star forming region's entire visible glow.
About three million years old, the Orion Nebula Cluster was
even more compact in its younger years and a
dynamical study
indicates that
runaway stellar collisions
at an earlier age may have formed a black hole
with more than 100 times the mass of the Sun.
The presence of a black hole within the cluster
could explain the observed high velocities of the Trapezium stars.
The Orion Nebula's distance of some 1,500 light-years
would make it the closest known black hole to planet Earth.
APOD: 2014 December 6 - Orion Launch
Explanation:
Headed for two orbits of planet Earth and a splashdown in the Pacific,
Orion
blazed into the early morning sky on Friday at 7:05am ET.
The
spacecraft was launched atop a United
Launch Aliance Delta IV Heavy rocket from Cape Canaveral
Air Force Station in Florida.
Its first voyage
into space on an uncrewed flight test,
the Orion traveled some 3,600 miles from Earth, about 15 times higher
than the orbital altitude of the International Space Station.
In fact, Orion traveled
farther
into space than any spacecraft designed
for astronauts since the Apollo missions
to the Moon.
The Orion crew module reached speeds of 20,000 miles per hour
and temperatures approaching 4,000 degrees Fahrenheit
as it re-entered Earth's atmosphere about 4.5 hours after launch.
APOD: 2014 November 11 - Orion in Gas, Dust, and Stars
Explanation:
The constellation of Orion holds much more than three stars in a row.
A deep exposure shows everything from dark nebulae to star clusters,
all embedded in an extended
patch of
gaseous wisps in the greater
Orion
Molecular
Cloud
Complex.
The brightest three stars
on the far left are indeed the
famous three stars that make up the
belt of Orion.
Just below Alnitak, the lowest of the
three belt stars, is the
Flame Nebula, glowing with
excited hydrogen gas and immersed in filaments of dark brown dust.
Below and left of the frame center and just to the right of
Alnitak lies the
Horsehead Nebula, a
dark indentation of
dense dust that has perhaps the most recognized nebular shapes on the sky.
On the upper right lies
M42, the
Orion Nebula,
an energetic caldron of tumultuous gas,
visible to the unaided eye,
that is giving birth to a
new open cluster of stars.
Immediately to the left of
M42
is a prominent bluish reflection nebula sometimes called the
Running Man that houses many bright
blue stars.
The featured image covers an area with objects that are roughly 1,500
light years away and spans about 75 light years.
APOD: 2014 June 28 - Orion Arising
Explanation:
Orion's belt runs just along the horizon, seen
through Earth's atmosphere and rising in
this
starry snapshot from low Earth orbit
on board the International Space Station.
The belt stars,
Alnitak, Alnilam, and Mintaka
run right to left
and Orion's sword,
home to the great Orion Nebula, hangs above his belt,
an orientation unfamiliar to
denizens of the planet's
northern hemisphere.
That puts
bright star Rigel, at the foot of Orion,
still higher above Orion's belt.
Of course the brightest celestial beacon in
the frame is Sirius, alpha star of the
constellation Canis Major.
The station's
Destiny Laboratory module is in the foreground
at the top right.
APOD: 2014 April 8 - M42: Inside the Orion Nebula
Explanation:
The Great Nebula in Orion,
an immense, nearby
starbirth region,
is probably the most famous of all
astronomical nebulas.
Here, glowing gas surrounds hot young stars at the edge of an
immense interstellar
molecular cloud only 1500
light-years away.
In the above deep image composite in assigned colors taken by the
Hubble Space Telescope
wisps and sheets of dust and gas are particularly evident.
The Great Nebula in Orion can be found with the
unaided eye near the
easily identifiable
belt of three stars in the popular constellation
Orion.
In addition to housing a bright
open cluster of stars known as the
Trapezium, the
Orion Nebula contains many
stellar nurseries.
These nurseries contain much
hydrogen gas, hot young stars,
proplyds, and
stellar jets
spewing material at high speeds.
Also known as
M42, the
Orion Nebula spans about 40 light years and is located in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2014 March 25 - Orion Nebula in Surrounding Dust
Explanation:
What surrounds a hotbed of star formation?
In the case of the
Orion Nebula -- dust.
The
entire Orion field, located about 1600
light years away, is inundated with intricate and
picturesque filaments of dust.
Opaque to visible light,
dust is created in the outer atmosphere of massive
cool stars and expelled by a strong outer wind of particles.
The Trapezium and other forming star clusters are embedded in the nebula.
The intricate filaments of dust surrounding
M42 and
M43 appear gray in the
above image, while central glowing gas is highlighted in brown and blue.
Over the next few million years much of
Orion's dust will be slowly destroyed by the very stars now being formed, or dispersed into the Galaxy.
APOD: 2014 March 24 - Orion and Aurora over Iceland
Explanation:
If you see a sky like this -- photograph it.
A month ago in Iceland, an adventurous photographer chanced across a
sky full of aurora and did just that.
In the foreground lies the stratovolcano
Öræfajökull.
In the background, among other sky delights, lies the constellation of
Orion, visible to the aurora's left.
Auroras
are sparked by
energetic particles from the
Sun impacting the
magnetic environment
around the Earth.
Resultant energetic particles such as
electrons and
protons
rain down near the Earth's poles and impact the air.
The impacted
air molecules obtain
excited electrons, and when electrons in
oxygen molecules fall back to their ground state,
they emit green light.
Auroras
are known to have many
shapes and
colors.
APOD: 2014 February 2 - Mars and Orion over Monument Valley
Explanation:
Welcome to
The World At Night.
Sharing the night sky seen around the world, this view from
Monument Valley,
USA includes a picturesque foreground of famous buttes.
Buttes
are composed of hard rock left behind after
water eroded away the surrounding soft rock.
The two buttes on the image left are known as the
Mittens,
while Merrick Butte is on the right.
Recorded in 2007 December,
planet Mars is at the left of the skyscape,
a glowing beacon of orange that is the brightest object in the frame.
To the right of Mars lies the
constellation of Orion.
Betelgeuse is the reddish star near
the center and the Belt of Orion
and the Orion Nebula
are farther right.
Finally, the bright blue star
Rigel
appears above Merrick Butte in this stunning view of
The World At Night.
APOD: 2014 January 15 - Spitzer's Orion
Explanation:
Few cosmic vistas excite the imagination like
the Orion Nebula,
an immense stellar nursery some 1,500 light-years away.
This stunning false-color
view spans about 40 light-years across the region,
constructed using
infrared data
from the Spitzer Space Telescope.
Compared to its
visual wavelength appearance,
the brightest portion of
the nebula is likewise centered on Orion's young, massive, hot stars,
known as the Trapezium Cluster.
But the infrared image also detects the nebula's many protostars, still
in the process of formation, seen here in red hues.
In fact, red spots along the dark dusty filament to the left
of the bright cluster include the protostar cataloged as HOPS 68,
recently
found to have
crystals of the silicate mineral olivine within its
protostellar envelope.
APOD: 2013 November 28 - NGC 1999: South of Orion
Explanation:
South of the large star-forming region known as the
Orion Nebula, lies bright blue reflection nebula
NGC 1999.
At the edge of the
Orion molecular
cloud complex some 1,500 light-years distant, NGC 1999's
illumination is provided by the
embedded variable star V380 Orionis.
That nebula is marked with a dark sideways T-shape near center in
this
cosmic vista that spans about 10 light-years.
The dark shape was once assumed to be an obscuring dust cloud
seen in silhouette against the bright reflection nebula.
But recent
infrared images
indicate the shape is likely a hole blown through the nebula
itself by energetic young stars.
In fact,
this
region abounds with energetic young stars
producing jets and outflows with luminous shock waves.
Cataloged as Herbig-Haro (HH) objects, named for astronomers
George Herbig and Guillermo Haro,
the shocks look like red gashes in
this scene that includes HH1 and HH2 just below NGC 1999.
The stellar jets
push through the surrounding
material at speeds of hundreds of kilometers per second.
APOD: 2013 October 29 - Horsehead and Orion Nebulas
Explanation:
The dark Horsehead Nebula and the glowing
Orion Nebula are contrasting cosmic vistas.
Adrift 1,500 light-years away in one of
the night sky's
most recognizable
constellations,
they appear in opposite corners of the above
stunning mosaic.
The familiar Horsehead
nebula appears as a dark cloud, a small silhouette
notched against the long red glow at the lower left.
Alnitak is the easternmost star in
Orion's belt and is seen as the
brightest star to the left of the
Horsehead.
Below Alnitak is the
Flame Nebula, with clouds of
bright emission and
dramatic dark dust lanes.
The magnificent emission region, the
Orion Nebula (aka M42), lies at the upper right.
Immediately to its left is a prominent
reflection nebula sometimes called the Running Man.
Pervasive tendrils
of glowing hydrogen gas are easily
traced
throughout the region.
APOD: 2013 June 4 - Orion Nebula in Oxygen, Hydrogen, and Sulfur
Explanation:
Few astronomical sights excite the imagination like the
nearby stellar nursery known as the Orion Nebula.
The Nebula's glowing gas
surrounds hot young stars at the edge of an immense interstellar
molecular cloud.
Many of the filamentary structures visible in the
above image are actually
shock waves -
fronts where fast moving material encounters slow moving gas.
The Orion Nebula spans about 40
light years
and is located about 1500 light years away in the
same spiral arm
of our Galaxy as the Sun.
The Great Nebula in
Orion can be found with the
unaided eye just below and to the left of the easily identifiable
belt of three stars in the popular constellation Orion.
The above image shows the nebula in three colors specifically emitted by
hydrogen,
oxygen, and
sulfur gas.
The whole Orion Nebula cloud complex,
which includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: 2013 March 20 - M42: Inside the Orion Nebula
Explanation:
The Great Nebula in Orion,
an immense, nearby
starbirth region,
is probably the most famous of all
astronomical nebulas.
Here, glowing gas surrounds hot young stars at the edge of an
immense interstellar
molecular cloud only 1500
light-years away.
In the above deep image in
assigned colors highlighted by
emission in
oxygen and
hydrogen,
wisps and sheets of dust and gas are particularly evident.
The Great Nebula in Orion can be found with the
unaided eye near the
easily identifiable
belt of three stars in the popular constellation
Orion.
In addition to housing a bright
open cluster of stars known as the
Trapezium, the
Orion Nebula contains many
stellar nurseries.
These nurseries contain much
hydrogen gas, hot young stars,
proplyds, and
stellar jets
spewing material at high speeds.
Also known as
M42, the
Orion Nebula spans about 40 light years and is located in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2013 February 13 - Infrared Orion from WISE
Explanation:
The Great Nebula in Orion is a intriguing place.
Visible to the unaided eye, it appears as a small
fuzzy patch in the
constellation of Orion.
But
this image, an illusory-color composite of four colors of
infrared light taken with the
Earth orbiting
WISE observatory, shows the
Orion Nebula
to be a bustling neighborhood or recently formed stars,
hot gas, and dark dust.
The power behind much of the
Orion Nebula (M42) is the stars of the
Trapezium star cluster, seen
near the center of the
above wide field image.
The eerie green glow surrounding the
bright stars pictured here is their own
starlight reflected
by intricate dust filaments that
cover much of the region.
The current
Orion Nebula cloud complex, which
includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: 2013 February 3 - LL Ori and the Orion Nebula
Explanation:
This esthetic close-up
of cosmic clouds and stellar winds
features LL Orionis, interacting with the
Orion Nebula flow.
Adrift in Orion's
stellar nursery
and still in its formative years, variable star
LL Orionis produces a wind more energetic than
the wind from our own
middle-aged Sun.
As the fast stellar wind runs into slow moving gas a shock front is
formed, analogous to the
bow
wave of a boat moving through water or
a plane traveling at supersonic speed.
The small, arcing, graceful structure just above and left of
center is LL Ori's cosmic
bow shock, measuring about half a light-year across.
The slower gas is flowing away from the
Orion Nebula's hot central star
cluster, the Trapezium, located off the upper left corner
of the picture.
In three dimensions,
LL Ori's wrap-around shock front is shaped like a
bowl that appears brightest when viewed along the "bottom" edge.
The beautiful picture is part of a
large mosaic view of
the complex
stellar nursery in Orion, filled with a myriad of
fluid
shapes associated with
star formation.
APOD: 2013 January 10 - The Orion Bullets
Explanation:
Cosmic bullets pierce the outskirts of
the Orion Nebula some 1500
light-years distant in this
sharp infrared close-up.
Blasted out by energetic massive star formation
the bullets, relatively dense,
hot gas clouds about
ten times the size of Pluto's orbit, are blue in the false color image.
Glowing with the light of ionized iron atoms they travel at speeds
of hundreds of kilometers per second,
their passage traced
by yellowish trails of the nebula's shock-heated
hydrogen gas.
The cone-shaped wakes are up to a fifth of a light-year long.
The detailed image was created using the 8.1 meter
Gemini South
telescope in Chile with a newly commisioned
adaptive optics system (GeMS).
Achieving a larger field of view than previous generation
adaptive optics,
GeMS uses
five laser generated guide stars
to help compensate for the blurring effects of planet Earth's
atmosphere.
APOD: 2012 December 21 - Orion over El Castillo
Explanation:
Welcome to the December
solstice, a day
the
world does not end ... even
according to the Mayan Calendar.
To celebrate, consider
this dramatic picture
of Orion rising
over El Castillo, the central pyramid at
Chichén Itzá, one of the great Mayan centers on the
Yucatán peninsula.
Also known as the Temple of Kukulkan it stands 30 meters tall
and 55 meters wide at the base.
Built up as a series of square terraces by the pre-Columbian
civilization between the 9th and 12th century,
the structure can be used as a calendar and is noted for
astronomical alignments.
In fact, the Mayans were accomplished astronomers and mathematicians,
accurately using the cyclic motions of the stars,
Sun, Moon, and planets to measure time and
construct calendars.
Peering through clouds in this night skyscape,
stars in the modern constellation Orion the Hunter
represented a turtle in the Mayan sky.
Tak
sáamal.
APOD: 2012 October 6 - At the Heart of Orion
Explanation:
Near the center of this sharp cosmic portrait, at
the heart of the Orion Nebula,
are four hot, massive stars
known as
the Trapezium.
Gathered within a region about 1.5 light-years in radius,
they dominate the core of the dense Orion Nebula Star Cluster.
Ultraviolet ionizing radiation from the Trapezium stars,
mostly from the brightest star
Theta-1
Orionis C
powers the complex star forming region's entire visible glow.
About three million years old, the Orion Nebula Cluster was
even more compact in its younger years and a
recent dynamical study
indicates that
runaway stellar collisions
at an earlier age may have formed a black hole
with more than 100 times the mass of the Sun.
The presence of a black hole within the cluster
could explain the observed high velocities of the Trapezium stars.
The Orion Nebula's distance of some 1500 light-years
would make it the closest known black hole to planet Earth.
APOD: 2012 July 15 - Orion Nebula: The Hubble View
Explanation:
Few cosmic vistas excite the imagination like
the Orion Nebula.
Also known as
M42,
the nebula's glowing gas surrounds hot young stars at the edge of an
immense interstellar
molecular cloud only 1,500 light-years away.
The Orion Nebula offers one of the best opportunities
to study how stars are born partly because it is the nearest large
star-forming region,
but also because the nebula's
energetic stars have
blown away
obscuring gas and dust clouds that would otherwise block
our view - providing an intimate look at a
range of ongoing stages
of
starbirth and evolution.
This detailed image of the
Orion Nebula is the sharpest ever, constructed using data from the
Hubble Space Telescope's
Advanced Camera for Surveys and the European Southern Observatory's
La Silla 2.2 meter telescope.
The mosaic
contains a billion pixels at full resolution
and reveals about 3,000 stars.
APOD: 2012 February 12 - Orion in Gas, Dust, and Stars
Explanation:
The constellation of Orion holds much more than three stars in a row.
A deep exposure shows everything from dark nebula to star clusters,
all embedded in an extended
patch of
gaseous wisps in the greater
Orion
Molecular
Cloud
Complex.
The brightest three stars
on the far left are indeed the
famous three stars that make up the
belt of Orion.
Just below Alnitak, the lowest of the
three belt stars, is the
Flame Nebula, glowing with
excited hydrogen gas and immersed in filaments of dark brown dust.
Below the frame center and just to the right of
Alnitak lies the
Horsehead Nebula, a
dark indentation of
dense dust that has perhaps the most recognized nebular shapes on the sky.
On the upper right lies
M42, the
Orion Nebula,
an energetic caldron of tumultuous gas,
visible to the unaided eye,
that is giving birth to a
new open cluster of stars.
Immediately to the left of
M42
is a prominent bluish reflection nebula sometimes called the
Running Man that houses many bright
blue stars.
The above image, a digitally stitched composite taken over several nights, covers an area with objects that are roughly 1,500
light years away and spans about 75 light years.
APOD: 2012 February 6 - Dust of the Orion Nebula
Explanation:
What surrounds a hotbed of star formation?
In the case of the
Orion Nebula -- dust.
The
entire Orion field, located about 1600
light years away, is inundated with intricate and
picturesque filaments of dust.
Opaque to visible light,
dust is created in the outer atmosphere of massive
cool stars and expelled by a strong outer wind of particles.
The Trapezium and other forming star clusters are embedded in the nebula.
The intricate filaments of dust surrounding
M42 and
M43 appear brown in the
above image, while central glowing gas is highlighted in red.
Over the next few million years much of
Orion's dust will be slowly destroyed by the very stars now being formed, or dispersed into the Galaxy.
APOD: 2012 January 23 - Deep Orion Over the Canary Islands
Explanation:
Which attracts your eye more -- the sky or the ground?
On the ground are rocky peaks in
Teide National Park on
Tenerife Island of the
Spanish
Canary Islands off the northwestern coast of
Africa.
The
volcanic landscape features old island summits and
is sometimes used as a testbed for instruments on
future Martian rovers.
The lights of a nearby hotel shine on the far left.
Storm clouds are visible on the horizon, artificially strutted from multiple exposures.
Dividing the sky, across the middle of the above deep image, is the
vertical band of the
Milky Way Galaxy.
The red circle on the right is
Barnard's Loop,
near the center of which are the famous
belt stars of the
constellation Orion.
Soon after the above image was taken, during an evening earlier this year,
storm clouds rolled across, and
indoor locations
began to attract eyes the most.
APOD: 2011 September 17 - Spitzer's Orion
Explanation:
Few cosmic vistas excite the imagination like
the Orion Nebula,
an immense stellar nursery some 1,500 light-years away.
This stunning false-color
view spans about 40 light-years across the region,
constructed using
infrared data
from the Spitzer Space Telescope.
Compared to its
visual wavelength appearance,
the brightest portion of
the nebula is likewise centered on Orion's young, massive, hot stars,
known as the
Trapezium
Cluster.
But the infrared image also detects the nebula's many protostars, still
in the process of formation, seen here in red hues.
In fact, red spots along the dark dusty filament to the left
of the bright cluster include the protostar cataloged as HOPS 68, recently
found to have
crystals of the silicate mineral olivine within its
protostellar envelope.
APOD: 2011 September 13 - Great Orion Nebulae
Explanation:
The Great Nebula
in Orion, also known as M42, is one of the
most famous nebulas in the sky.
The star forming region's glowing gas clouds and hot young stars
are on the right in this sharp and colorful image that includes the smaller
nebula M43
near center and dusty, bluish reflection nebulae
NGC 1977 and friends on the left.
Located at the edge of an otherwise invisible
giant molecular
cloud complex,
these eye-catching nebulae represent only a small
fraction of this galactic neighborhood's wealth of
interstellar material.
Within the well-studied stellar nursery, astronomers have also
identified what appear to be numerous
infant planetary systems.
The gorgeous skyscape spans nearly two degrees or about 45
light-years
at the Orion Nebula's estimated distance of 1,500 light-years.
APOD: 2011 February 24 - NGC 1999: South of Orion
Explanation:
South of the large star-forming region known as the
Orion Nebula, lies bright blue reflection nebula
NGC 1999.
Also at the edge of the
Orion molecular
cloud complex some 1,500 light-years distant, NGC 1999's
illumination is provided by the
embedded variable star V380 Orionis.
The nebula is marked with a dark sideways T-shape near center in this
broad
cosmic vista that spans over 10 light-years.
The dark shape was once assumed to be an obscuring dust cloud
seen in silhouette against the bright reflection nebula.
But recent
infrared images
indicate the shape is likely a hole blown through the nebula
itself by energetic young stars.
In fact,
this
region abounds with energetic young stars
producing jets and outflows that create luminous shock waves.
Cataloged as Herbig-Haro (HH) objects, named for astronomers
George Herbig and Guillermo Haro,
the shocks appear bright red in
this view that includes
HH1 and HH2 just below NGC 1999.
The stellar jets and
outflows push through the surrounding
material at speeds of hundreds of kilometers per second.
APOD: 2011 February 11 - Star Colors in Orion
Explanation:
What determines
a star's color?
Its temperature.
Red stars are cool, with surface temperatures of around 3,000
kelvins (K),
while blue stars are hotter and can have temperatures over 30,000 K.
Our own lovely "yellow" Sun's temperature is a
comforting 6,000 K.
Differences in star colors are particularly easy to see
in this intriguing composite view of
the constellation Orion, made while experimenting with a star trail
step-focus technique.
In it, a series of 35 consecutive exposures were combined to produce
trails of stars moving left to right through
the frame, while changing focus in steps.
Beginning and ending with the camera out of focus
produced a sharply focused exposure near the middle of
the series and blurs the star trails into a bow tie shape.
For the brighter stars, blurring produces more saturated colors
in the images.
At the upper left, Orion's cool red
supergiant Betelgeuse
stands out from the other, hotter, bluish stars composing
the body of the constellation.
Not a star at all, the
Orion Nebula contributes a
pinkish tint below center.
Also remarkable in the field, the fainter step focus
trail of cool, deep red carbon star
W Orionis
is near the center right edge, its red hue enhanced by a
carbon-rich composition.
APOD: 2010 December 26 - Sideways Orion Over Snowy Ireland
Explanation:
Orion always comes up sideways ... and was caught in the
act earlier this month by over a snowy landscape in
Donegal,
Ireland.
To compose this serene picture, the photographer found a
picturesque setting to the east, waited until after sunset, and then momentarily lit the foreground with a flashlight.
The three bright stars in
Orion's belt stand in a
nearly vertical line above the snow covered road at the bottom.
Hanging from his belt, the stars and
nebulae of the
Hunter's sword are visible lower and to the right.
Yellow-orange Betelgeuse is the brightest star on the image left.
As winter progresses in Earth's northern hemisphere,
Orion
will rise earlier and so appear continually higher in the sky at sunset.
APOD: 2010 November 17 - Frosted Leaf Orion
Explanation:
Sometimes, you can put some night sky in your art.
Captured above
Japan earlier this month, a picturesque night sky was photographed behind a picturesque frosted leaf.
The reflecting ice crystals on the leaf coolly mimic the shining stars far in the background.
The particular background sky on
this 48-second wide angle exposure,
however, might appear quite interesting and familiar.
On the far left, although hard to find, appears a
streaking meteor.
Below and to the right of the meteor appears a longer and brighter streak of an airplane.
The bright star on the left is the dog-star
Sirius, the brightest star on the night sky.
To Sirius' right appears the
constellation of Orion, including the three linear belt stars below the red giant
Betelgeuse.
The bright patch of light further to the right is the
Pleiades
open star cluster.
Similar views including the constellation
Orion can be seen above much of the northern hemisphere for the next several months,
although you might have to provide your own leaf.
APOD: 2010 October 23 - Orion: Head to Toe
Explanation:
Cradled in cosmic dust and glowing hydrogen,
stellar
nurseries in Orion the
Hunter
lie at
the edge of a giant molecular cloud some 1,500 light-years away.
Spanning nearly 25 degrees, this breath-taking vista
stretches across the well-known constellation
from head to toe
(left to right).
The Great Orion
Nebula, the closest large star forming region, is right of center.
To its left are the
Horsehead Nebula,
M78, and
Orion's belt stars.
Sliding your cursor over the picture will also find
red giant Betelgeuse at the hunter's shoulder,
bright blue Rigel
at his foot, and the glowing Lambda Orionis
(Meissa) nebula at the far left, near Orion's head.
Of course, the Orion Nebula and bright stars are
easy to see with the
unaided eye, but dust clouds and emission from the extensive interstellar
gas in this nebula-rich complex,
are too faint and much harder to record.
In this mosaic of broadband telescopic images, additional image
data acquired with a narrow
hydrogen alpha filter was used to
bring out the pervasive tendrils of energized
atomic hydrogen gas and the arc of the giant
Barnard's Loop.
APOD: 2010 October 5 - Horsehead and Orion Nebulas
Explanation:
The dark Horsehead Nebula and the glowing
Orion Nebula are contrasting cosmic vistas.
Adrift 1,500 light-years away in one of
the night sky's
most recognizable
constellations,
they appear in opposite corners of the above
stunning mosaic.
The familiar Horsehead
nebula appears as a dark cloud, a small silhouette
notched against the long red glow at the lower left.
Alnitak is the easternmost star in
Orion's belt and is seen as the
brightest star to the left of the
Horsehead.
Below Alnitak is the
Flame Nebula, with clouds of
bright emission and
dramatic dark dust lanes.
The magnificent emission region, the
Orion Nebula (aka M42), lies at the upper right.
Immediately to its left is a prominent bluish
reflection nebula sometimes called the Running Man.
Pervasive tendrils
of glowing hydrogen gas are easily
traced
throughout the region.
APOD: 2010 April 10 - Spitzer's Orion
Explanation:
Few cosmic vistas excite the imagination like
the Orion Nebula,
an immense stellar nursery some 1,500 light-years away.
Spanning about 40 light-years across the region,
this new infrared image
from the Spitzer Space Telescope was constructed from data intended to
monitor
the brightness of the nebula's young stars, many still surrounded
by dusty, planet-forming disks.
Orion's young stars are only about 1 million years old,
compared to the Sun's age of 4.6 billion years.
The region's hottest stars are found in the
Trapezium Cluster, the brightest cluster
near picture center.
Spitzer's liquid helium
coolant ran out in May 2009,
so this false color view is from two
channels that still remain sensitive to
infrared light
at warmer operating temperatures.
APOD: 2010 March 2 - M78 and Reflecting Dust Clouds in Orion
Explanation:
An eerie blue glow and ominous columns of
dark dust highlight M78 and other bright
reflection nebula
in the constellation of Orion.
The dark filamentary
dust not only absorbs light, but also reflects the
light of several bright blue stars that
formed recently in the nebula.
Of the two reflection nebulas
pictured above, the more famous nebula is
M78, in the image center, while
NGC 2071 can be seen to its lower left.
The same type of scattering that colors the
daytime sky further enhances the blue color.
M78
is about five
light-years across and visible through a small telescope.
M78 appears above only as it was
1600 years ago,
however, because that is how long it takes light to go from
there to here.
M78
belongs to the larger
Orion
Molecular
Cloud
Complex
that contains the
Great Nebula in Orion and the
Horsehead Nebula.
APOD: 2009 December 22 - Planetary Systems Now Forming in Orion
Explanation:
How do planets form?
To help find out, the
Hubble Space Telescope
was tasked to take a detailed look
at one of the more interesting of all astronomical
nebulae, the Great Nebula in Orion.
The Orion nebula, visible with the
unaided eye near the
belt in the
constellation of Orion,
is an immense nearby
starbirth region and
probably the most famous of all astronomical nebulas.
Insets to the above mosaic show
numerous proplyds, many of which are stellar nurseries likely harboring
planetary systems in formation.
Some proplyds glow as close disks surrounding bright stars light up, while other
proplyds
contain disks further from their host star, contain cooler
dust, and hence appear as dark
silhouettes against brighter gas.
Studying this dust, in particular, is giving insight for how planets are forming.
Many proplyd images also show
arcs that are
shock waves
- fronts where fast moving material encounters slow moving gas.
The Orion Nebula lies about 1,500
light years distant and is located in the same
spiral arm of
our Galaxy
as our Sun.
APOD: 2009 October 2 - Comet and Orion
Explanation:
These colorful panels both
feature a familiar astronomical sight: the stellar nursery known as
the Great Orion Nebula.
They also offer an intriguing and unfamiliar detail of the
nebula rich skyscape -- a passing comet.
Recorded this weekend with a remotely operated telescope in
New Mexico, the right hand image was taken on
September 26 and
the left on September 27.
Comet 217P Linear
sports an extended greenish tail and lies
above the bluish
Running Man
reflection nebula near the top of
both frames.
Nearby and moving rapidly through the night sky, the comet's
position clearly shifts against the cosmic nebulae and background
stars from one night to the next.
In fact, the comet was a mere 5 light-minutes away on September
27, compared to 1,500 light-years for the Orion Nebula.
Much too faint to be seen with the unaided eye,
Comet
217P Linear
is a small periodic comet with an orbital period of
about 8 years.
At its most distant point from the Sun,
the comet's
orbit is calculated to reach beyond the orbit of Jupiter
At its closest point to the Sun, the comet still lies just
beyond the orbit of planet Earth.
APOD: 2009 September 29 - Orion in Gas, Dust, and Stars
Explanation:
The constellation of Orion holds much more than three stars in a row.
A deep exposure shows everything from dark nebula to star clusters,
all imbedded in an extended
patch of
gaseous wisps in the greater
Orion
Molecular
Cloud
Complex.
The brightest three stars
on the far left are indeed the
famous three stars that make up the
belt of Orion.
Just below Alnitak, the lowest of the
three belt stars, is the
Flame Nebula, glowing with
excited hydrogen gas and immersed in filaments of dark brown dust.
Below the frame center and just to the right of
Alnitak lies the
Horsehead Nebula, a
dark indentation of
dense dust that has perhaps the most recognized nebular shapes on the sky.
On the upper right lies
M42, the
Orion Nebula,
an energetic caldron of tumultuous gas,
visible to the unaided eye,
that is giving birth to a
new open cluster of stars.
Immediately to the left of
M42
is a prominent bluish reflection nebula sometimes called the
Running Man that houses many bright blue stars.
The
above image, a digitally stitched composite taken over several nights, covers an area with objects that are roughly 1,500
light years away and spans about 75 light years.
APOD: 2009 August 26 - Classic Orion Nebulae
Explanation:
The Great Nebula
in Orion, also known as M42, is one of the
most famous nebulae in the sky.
The star forming region's glowing gas clouds and hot young stars
are near the center of this colorful
deep
sky image that includes the smaller
nebula M43
and dusty, bluish reflection nebulae
NGC 1977 and friends on the left.
Located at the edge of an otherwise invisible giant molecular
cloud
complex, these eye-catching nebulae represent only a small
fraction of this galactic neighborhood's wealth of
interstellar
material.
Captured with very modest equipment, the gorgeous skyscape was
awarded Best in Show at the
2009
Starfest International Salon of Astrophotography.
Judges commented that the detail and shading were exquisite
in this version of a classic astronomical image.
The field spans nearly 3 degrees or about 75 light-years
at the Orion Nebula's estimated distance of 1,500 light-years.
APOD: 2009 March 10 - Horsehead and Orion Nebulae
Explanation:
Adrift 1,500 light-years away in one of
the night sky's
most recognizable
constellations, the glowing
Orion Nebula and the dark
Horsehead Nebula are contrasting
cosmic vistas.
They appear in opposite corners of this
stunning mosaic taken with a digital camera attached to a small telescope.
The magnificent emission region, the
Orion Nebula (aka M42), lies at the upper right of the picture.
Immediately to its left is a prominent bluish
reflection nebula sometimes called
the Running Man.
The Horsehead
nebula appears as a dark cloud, a small silhouette
notched against the long red glow at the lower left.
Alnitak is the easternmost star in
Orion's belt and is seen as the
brightest star to the left of the
Horsehead.
Below Alnitak is the
Flame Nebula, with clouds of
bright emission and dramatic dark dust lanes.
Pervasive tendrils
of glowing hydrogen gas are easily
traced
throughout the region in
this deep field image of the same region.
APOD: 2009 February 22 - Orion Nebula: The Hubble View
Explanation:
Few cosmic vistas excite the imagination like
the Orion Nebula.
Also known as
M42,
the nebula's glowing gas surrounds hot young stars at the edge of an
immense interstellar
molecular cloud only 1,500 light-years away.
The Orion Nebula offers one of the best opportunities
to study how stars are born partly because it is the nearest large
star-forming region,
but also because the nebula's
energetic stars have
blown away
obscuring gas and dust clouds that would otherwise block
our view - providing an intimate look at a
range of ongoing stages
of
starbirth and evolution.
This detailed image of the
Orion Nebula is the sharpest ever, constructed using data from the
Hubble Space Telescope's
Advanced Camera for Surveys and the European Southern Observatory's
La Silla 2.2 meter telescope.
The mosaic
contains a billion pixels at full resolution
and reveals about 3,000 stars.
APOD: 2009 February 11 - Orion s Belt Continued
Explanation:
Yesterday's skyscape featured
Alnitak, Alnilam, and Mintaka,
the stars of
Orion's Belt.
Today's also presents the easternmost belt star, Alnitak, at the
bottom right of the field, surrounded by the well-known
Horsehead
and Flame nebulae.
But this view sweeps
farther to the east (left) and north (top)
detailing subtler cosmic clouds of gas and dust scattered through
the fertile, nebula rich region.
The scene is anchored at the top left by the eerie
blue glow
and ominous dark dust lanes of
reflection
nebula M78.
Like the Horsehead, the Flame, and the
Orion Nebula itself,
M78 is a readily visible part of the large
Orion
Molecular Cloud complex some 1,500 light-years distant.
APOD: 2009 February 10 - Orion s Belt
Explanation:
Alnitak,
Alnilam,
and
Mintaka,
are the bright bluish stars
from east to west (left to right) along the diagonal in
this gorgeous cosmic vista.
Otherwise known as the
Belt of Orion, these
three blue supergiant stars are hotter and much more
massive than the Sun.
They lie about 1,500 light-years away, born
of Orion's
well-studied interstellar clouds.
In fact, clouds of gas and dust adrift in
this region have
intriguing and some surprisingly familiar shapes, including the
dark Horsehead
Nebula and Flame Nebula near
Alnitak at the lower
left.
The famous Orion Nebula
itself lies off the bottom of this
star field
that covers about 4.5x3.5 degrees on the sky.
This
image was taken last month with a digital camera attached to a small
telescope in
Switzerland,
and better matches
human color
perception
than a more detailed composite taken over 15
years ago.
APOD: 2008 December 16 - Orion Dawn Over Mount Nemrut
Explanation:
What's that in front of Orion?
Forty kilometers north of
Kahta,
Turkey,
lies
Mount Nemrut, a mountain adorned with the fragments of vast statues built over 2000 years ago.
The
stone sculptures
once stood nearly 10 meters high and depicted lions,
eagles,
various ancient
gods, and
King Antiochus I Theos, who ruled
Commagene
from 86 BC to 38 BC.
Ruins of the bodies of several sitting
figures are visible on the hill above, illuminated by
moonlight.
Zeus'
head can be found near the above image's center,
while the king's head is seen next closest to the horizon.
Visible far in the distance in
this image, taken three months ago, is the familiar
constellation of Orion.
The red patch just below
Orion's belt is the
Orion Nebula,
while the bright star to the left of Orion is
Sirius.
On the far left, a red and brightening horizon announces that the Sun is beginning to rise.
APOD: 2008 November 26 - The Horsehead Nebula in Orion
Explanation:
One of the most identifiable nebulae in the sky,
the Horsehead Nebula in Orion, is part of a large, dark,
molecular cloud.
Also known as Barnard 33, the unusual shape was first
discovered on a
photographic plate in the late 1800s.
The red glow originates from
hydrogen
gas predominantly behind the nebula, ionized by the nearby bright star
Sigma Orionis.
A blue
reflection nebula dubbed
NGC 2023 surrounds the bright star at the lower left.
The darkness of the
Horsehead is caused mostly by thick
dust,
although the lower part of the
Horsehead's neck casts a shadow to the left.
Streams of gas leaving the nebula are funneled by a strong
magnetic field.
Bright spots in the
Horsehead Nebula's base are
young stars just in the process of forming.
Light takes about 1500 years to reach us from the
Horsehead Nebula.
The above image
was taken earlier this month with a 0.6-meter telescope at the
Mt. Lemmon SkyCenter in
Arizona,
USA.
APOD: 2008 October 23 - Great Orion Nebulae
Explanation:
The Great Nebula
in Orion, also known as M42, is one of the
most famous nebulae in the sky.
The star forming region's glowing gas clouds and hot young stars
are on the right in this sharp and colorful
two frame mosaic
that includes the smaller
nebula M43
near center and dusty, bluish reflection nebulae
NGC 1977 and friends on the left.
Located at the edge of an otherwise invisible giant molecular
cloud complex,
these eye-catching nebulae represent only a small
fraction of this galactic neighborhood's wealth of
interstellar material.
Within the well-studied stellar nursery, astronomers have also
identified what appear to be numerous
infant solar systems.
The gorgeous skyscape spans nearly two degrees or about 45 light-years
at the Orion Nebula's estimated distance of 1,500 light-years.
APOD: 2008 October 15 - Camera Orion
Explanation:
Orion, the Hunter, is one of the most easily recognizable
constellations
in planet Earth's night sky.
But Orion's stars and
nebulas don't look
quite as colorful to the eye as they do in
this lovely camera image, taken
early last month at the
Black Forest Star Party from
Cherry Springs State Park in
Pennsylvania,
USA.
In this single exposure, cool red giant
Betelgeuse
takes on a yellowish tint as the brightest star at the far left.
Otherwise Orion's hot blue stars are numerous, with
supergiant Rigel balancing Betelgeuse at the upper right, Bellatrix at the upper left, and
Saiph at the lower right.
Lined up in Orion's belt (bottom to top) are
Alnitak, Alnilam, and Mintaka
all about 1,500
light-years away, born of the constellation's well studied
interstellar
clouds.
And if the middle "star" of
Orion's sword
looks reddish and fuzzy to you, it should.
It's the stellar nursery known as the
Great Nebula of Orion.
APOD: 2008 April 8 - Southern Orion: From Belt to Witch
Explanation:
Do you recognize the belt of Orion in this image?
The familiar trio of stars,
visible to the unaided eye,
can be found across the upper left.
Otherwise, the southern part of the constellation Orion has taken
on a new look in
this unusually deep and wide view
First note that the lower left belt star,
Alnitak,
is the easternmost star in Orion's belt.
Left of Alnitak is the Flame Nebula,
with clouds of bright emission and dramatic dark dust lanes.
Directly below
Alnitak,
a close inspection will reveal the
Horsehead Nebula.
Farther right and below is the Orion Nebula,
M42,
itself visible to the unaided eye.
The brightest star in the frame, near the bottom right, is
Rigel.
A bright blue star, Rigel illuminates the ominously shaped dust patch known as the
Witch Head Nebula, visible as the
blue reflection nebula near the
lower right corner.
Finally, appearing as a vast red ring and encompassing the entire region, is
Barnard's Loop.
Humans
could see this entire menagerie, unaided, were their eyes
about 10,000 times more sensitive.
APOD: 2008 April 3 - South of Orion
Explanation:
This tantalizing array of nebulae and stars can be found
about 2 degrees south of the famous
star-forming Orion Nebula.
The
region abounds with energetic young stars producing jets and
outflows that push through the surrounding
material at speeds of hundreds of kilometers per second.
The interaction creates luminous shock
waves known as
Herbig-Haro (HH) objects.
For example, the graceful, flowing arc just right of center
is cataloged as HH 222, also called the Waterfall Nebula.
Seen below the Waterfall, HH 401 has a distinctive cone shape.
The bright bluish nebula below and left of center
is NGC 1999, a dusty cloud reflecting
light from an embedded variable star.
The entire cosmic vista
spans over 30 light-years, near the edge of the
Orion
molecular cloud
complex
some 1,500 light-years distant.
APOD: 2008 March 18 - M78 and Reflecting Dust Clouds in Orion
Explanation:
An eerie blue glow and ominous columns of dark dust highlight M78 and other bright
reflection nebula
in the constellation of Orion.
The dark filamentary
dust not only absorbs light, but also reflects the
light of several bright blue stars that
formed recently in the nebula.
Of the two reflection nebulas pictured above, the more famous nebula is M78, on the upper right, while NGC 2071 can be seen to its lower left.
The same type of scattering that colors the
daytime sky further enhances the blue color.
M78
is about five
light-years across and visible through a small telescope.
M78 appears
above only as it was 1600 years ago, however, because that is how long it takes light to go from
there to here.
M78
belongs to the larger
Orion Molecular Cloud Complex
that contains the
Great Nebula in Orion and the
Horsehead Nebula.
APOD: 2008 February 21 - Orion's Horsehead Nebula
Explanation:
The Horsehead
Nebula is one of the most famous nebulae on the sky.
It is visible as the dark indentation to the red
emission nebula seen just below
and left of center in the
this photograph.
The brightest star on the left is located in the belt of the familiar
constellation Orion.
The horse-head
feature is dark because it is really an opaque
dust cloud that lies in
front of the bright red
emission nebula.
Like clouds in
Earth's atmosphere, this cosmic cloud has
assumed a
recognizable
shape by chance.
After many thousands of years, the internal motions of the cloud
will alter its appearance.
The emission nebula's red color is caused by
electrons recombining
with
protons
to form
hydrogen atoms.
Also visible in the picture are blue
reflection nebulae that
preferentially reflect the blue light from
nearby stars.
APOD: 2007 December 25 - Mars and Orion Over Monument Valley
Explanation:
Welcome to
The World At Night.
Sharing the night sky seen around the world, this view from
Monument Valley,
USA includes a picturesque foreground of famous buttes.
Buttes
are composed of hard rock left behind after
water eroded away the surrounding soft rock.
The two buttes on the image left are known as the
Mittens,
while Merrick Butte is on the right.
Recorded just last week,
planet Mars is at the left of the skyscape,
a glowing beacon of orange that is the brightest object in the frame.
To the right of Mars lies the
constellation of Orion.
Betelgeuse is the reddish star near
the center and the Belt of Orion
and the Orion Nebula
are farther right.
Finally, the bright blue star
Rigel
appears above Merrick Butte in this stunning view of
The World At Night.
APOD: 2007 October 6 - X-Ray Stars of Orion
Explanation:
The stars of Orion shine brightly
in visible light in planet Earth's night sky.
The
constellation harbors the closest large stellar nursery,
the Great Nebula of Orion,
a mere 1,500 light-years away.
In fact, the apparently bright clump of stars near the center
of this false color Chandra
x-ray telescope picture
are the massive stars of
the Trapezium - the
young star cluster which powers much of the nebula's
visible-light glow.
The stars shown
in blue and orange are young sun-like stars; prodigious sources
of x-rays thought to be produced in hot
stellar coronae and
surface flares in a young star's strong
magnetic field.
Our middle-aged
Sun itself was
probably thousands of times
brighter in x-rays when, like
the
Trapezium stars, it was
only a few million years old.
The
x-ray image
spans about 2.5 light-years
across the central region of the Orion Nebula.
APOD: 2007 May 11 - LDN 1622: Dark Nebula in Orion
Explanation:
The silhouette of an intriguing
dark nebula
inhabits this cosmic scene, based on images from the
Palomar
Observatory Sky Survey.
Lynds' Dark Nebula
(LDN) 1622 appears against a faint background
of glowing hydrogen gas only easily seen in long telescopic
exposures of the region.
LDN 1622 lies near the plane of our Milky Way Galaxy,
close on the sky to
Barnard's
Loop - a large cloud surrounding the rich
complex of emission nebulae found
in the Belt and Sword
of Orion.
But the obscuring dust of LDN 1622 is thought to be much closer
than Orion's more famous nebulae, perhaps only 500 light-years away.
At that distance, this 1 degree wide field of view
would span less than 10 light-years.
APOD: 2007 March 26 - Bullet Pillars in Orion
Explanation:
Why are bullets of gas shooting out of the Orion Nebula?
Nobody is yet sure.
First discovered in 1983, each bullet is actually about the size of
our Solar System, and
moving at about 400 km/sec from a central source dubbed IRc2.
The age of the bullets, which can be found from their speed and distance from
IRc2, is very young -- typically less than 1,000 years.
As the
bullets rip through the interior of the
Orion Nebula,
a small percentage of iron gas causes the tip of each bullet to glow blue,
while each bullet leaves a tubular pillar that glows by the light of heated hydrogen gas.
Pictured above, the Orion bullets were captured in unprecedented detail by the adaptive optics technology of the Gemini North telescope.
M42, the Orion Nebula,
is the closest major star forming region to us and filled with changing
dust, gas, and bright stars.
The Orion Nebula, is located about 1,500
light years away and
can be seen with the unaided eye toward the
constellation of Orion.
APOD: 2007 January 25 - Orion's Cradle
Explanation:
Cradled in glowing hydrogen,
stellar
nurseries in Orion
lie at
the edge of a giant molecular cloud some 1,500 light-years away.
This breath-taking view
spans about 13 degrees across
the center of the well-known constellation with the
Great Orion
Nebula, the closest large star forming region,
just right of center.
The deep mosaic
also
includes (left of center), the Horsehead
Nebula, the Flame Nebula, and Orion's belt stars.
Image data acquired with a
hydrogen alpha filter adds
other remarkable features to this wide angle
cosmic vista -- pervasive tendrils of energized
atomic hydrogen gas and portions of the surrounding
Barnard's Loop.
While the Orion Nebula and belt stars are easy to see with the
unaided eye, emission from the extensive interstellar
gas is faint and much harder to record, even in telescopic views of the
nebula-rich complex.
APOD: 2007 January 6 - The Orion Deep Field
Explanation:
Adrift 1,500 light-years away in one of
the night sky's most recognizable
constellations, the glowing
Orion Nebula and the dark
Horsehead Nebula are contrasting
cosmic vistas.
But even fainter filaments of glowing gas are easily traced
throughout the region in
this
stunning composite image
that includes exposures filtered to record emission
from hydrogen atoms.
The view reveals extensive
nebulosities associated with
the giant Orion Molecular
Cloud
complex, itself hundreds of light-years across.
A magnificent emission region, the
Orion
Nebula (aka M42) lies at the
upper right of the picture.
Immediately to its left are a cluster of prominent bluish
reflection nebulae sometimes called
the Running Man.
The Horsehead
nebula appears as a dark cloud, a small silhouette
notched against the long red glow left of center.
Alnitak is the easternmost star in Orion's belt and
the brightest star to the left of the Horsehead.
Below Alnitak is the
Flame Nebula, with clouds of
bright emission and dramatic dark dust lanes.
Completing the trio of Orion's belt
stars, bluish Alnilam and Mintaka form a line with Alnitak,
extending to the upper left.
APOD: 2006 December 16 - A Path To Orion
Explanation:
Last Saturday, the
Space
Shuttle Discovery lit up the night
as it climbed into orbit
above planet Earth.
From Oak Hill, Florida, USA - about 30 miles north
of the Kennedy Space Center - design engineer
Andrew Arigema tracked the shuttle and recorded a four minute
time exposure of the exhaust plume
along Discovery's path against the background of the starry sky.
At the upper left, the end of the drifting plume is
punctuated by
Alnitak, Alnilam, and Mintaka in a vertical line, the belt
stars of Orion.
To the right of the belt stars, the pinkish jewel
in Orion's sword is not a star at all, but the great
Orion Nebula.
Still farther to the right, at the foot of the hunter, lies Rigel,
the brightest star in view.
Rigel is
a hot supergiant star some 700 light-years in the distance.
APOD: 2006 December 8 - NGC 2174: Emission Nebula in Orion
Explanation:
A lesser known sight in the
nebula-rich constellation Orion,
NGC 2174
can be found with binoculars near the head of the
celestial hunter.
About 6,400 light-years distant, the glowing cosmic cloud surrounds
loose clusters of young stars.
Covering an area larger than the full Moon on the sky,
this stunning
narrow band image adopts a typical color mapping of
the atomic emission from NGC 2174.
The false-color mapping
shows otherwise red hydrogen emission in green
hues and emphasizes sulfur emission in red and oxygen in blue.
Placing your cursor on the image will reveal an alternative image
of the nebula made through broad band
filters.
The broad band image combines filters in a
closer analogy
to human vision, dominated by the
red glow of hydrogen.
APOD: 2006 November 20 - M42: Wisps of the Orion Nebula
Explanation:
The Great Nebula in Orion, an immense, nearby
starbirth region,
is probably the most famous of all
astronomical nebulas.
Here, glowing gas surrounds hot young stars at the edge of an
immense interstellar
molecular cloud only 1500
light-years away.
In the above deep image, faint wisps and sheets of
dust and gas are particularly evident.
The Great Nebula in Orion can be found with the
unaided eye just below and to the left of the
easily identifiable
belt of three stars in the popular constellation Orion.
In addition to housing a bright
open cluster of stars known as the
Trapezium, the
Orion Nebula contains many
stellar nurseries.
These nurseries contain
hydrogen gas, hot young stars,
proplyds, and
stellar jets
spewing material at high speeds.
Also known as
M42, the
Orion Nebula spans about 40 light years and is located in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2006 October 15 - An Orion Deep Field
Explanation:
Adrift 1,500 light-years away in one of
the night sky's
most recognizable
constellations, the glowing
Orion Nebula and the dark
Horsehead Nebula are contrasting
cosmic vistas.
They both appear in this stunning composite digital image
assembled from over 20 hours of data that includes exposures
filtered to record emission from hydrogen
atoms.
The view reveals extensive
nebulosities associated with
the giant Orion Molecular
Cloud
complex, itself hundreds of light-years across.
The magnificent emission region, the
Orion
Nebula (aka M42), lies at the
upper right of the picture.
Immediately to its left are a cluster of
of prominent bluish
reflection nebulae sometimes called
the Running Man.
The Horsehead
nebula appears as a dark cloud, a small silhouette
notched against the long red glow at the lower left.
Alnitak is the easternmost star in Orion's belt and
is seen as the brightest star to the left of the Horsehead.
Below Alnitak is the
Flame Nebula, with clouds of
bright emission and dramatic dark dust lanes.
Fainter tendrils of glowing hydrogen gas are easily traced
throughout the region in
this
Orion deep field.
APOD: 2006 October 10 - Reflection Nebulas in Orion
Explanation:
In the vast
Orion Molecular Cloud complex,
several bright blue nebulas are particularly apparent.
Pictured above are two of the most prominent
reflection nebulas -
dust clouds lit by the
reflecting light of bright embedded stars.
The more famous nebula is
M78,
near the image center, cataloged over 200 years ago.
On the upper left is the lesser known
NGC 2071.
The image was taken with the
Mayall 4-meter telescope
on Kitt Peak,
Arizona,
USA.
Astronomers continue to
study these
reflection nebulas to better understand how interior stars form.
The Orion complex
lies about 1500 light-years distant, contains the
Orion and
Horsehead nebulas,
and covers much of the
constellation of Orion.
APOD: 2006 August 18 - Spitzer's Orion
Explanation:
Few cosmic vistas excite the imagination like
the Orion Nebula,
an immense stellar nursery some 1,500 light-years away.
Also known as M42, the nebula is
visible to the unaided eye,
but this
stunning infrared view from the
Spitzer Space
Telescope
penetrates the turbulent cosmic gas and
dust clouds to
explore
the region in unprecedented detail.
At full resolution, the remarkable image data yields
a census of new stars and potential solar systems.
About 2,300 young stars surrounded by
planet-forming disks
were detected based on the
infrared glow of their warm dust,
along with about 200 stellar
embryos,
stars too young to have developed disks.
This 0.8 by 1.4 degree false-color image is
about 20 light-years wide at the distance of the
Orion
Nebula.
APOD: 2006 January 30 - NGC 1999: South of Orion
Explanation:
South
of the large star-forming region known as the
Orion Nebula, lies bright blue reflection nebula
NGC 1999.
The nebula is marked with a dark inverted T-shape at the
lower left in a
broad
cosmic vista that spans over 10 light-years.
The dark shape is a dense gas and dust cloud, or
Bok globule,
seen in silhouette against the bright nebula, and likely
a site of future star formation.
At the edge of the
Orion molecular
cloud complex some 1,500 light-years distant, NGC 1999's
illumination is provided by the
embedded variable star V380 Orionis.
The
region abounds with energetic young stars
producing jets and outflows that create luminous shock waves,
including HH (Herbig-Haro) 1 and 2 just below and left of NGC 1999, and
the apparent cascade
of reddish arcs and bow shocks beginning at the upper right.
The stellar jets and
outflows push through the surrounding
material at speeds of hundreds of kilometers per second.
APOD: 2006 January 20 - LL Ori and the Orion Nebula
Explanation:
This esthetic close-up
of cosmic clouds and stellar winds
features LL Orionis, interacting with the
Orion Nebula flow.
Adrift in Orion's
stellar nursery
and still in its formative years,
variable star LL Orionis produces a wind more
energetic than
the wind from our own
middle-aged Sun.
As the fast stellar wind runs into slow moving gas a shock front is
formed, analogous to the
bow
wave of a boat moving through water or
a plane traveling at supersonic speed.
The small, arcing, graceful structure just above and left of
center is LL Ori's cosmic
bow shock, measuring about half a light-year across.
The slower gas is flowing away from the Orion Nebula's hot central star
cluster, the Trapezium, located off the upper left corner
of the picture.
In three
dimensions, LL Ori's wrap-around shock front is shaped like a
bowl that appears brightest when viewed along the "bottom" edge.
The beautiful picture is part of a
large mosaic view of
the complex
stellar nursery in Orion, filled with a myriad of
fluid
shapes associated with
star formation.
APOD: 2006 January 19 - Orion Nebula, The Hubble View
Explanation:
Few cosmic vistas excite the imagination like
the Orion Nebula.
Also known as
M42,
the nebula's glowing gas surrounds hot young stars at the edge of an
immense interstellar molecular cloud only 1,500 light-years away.
The Orion Nebula offers one of the best opportunities
to study how stars are born partly because it is the nearest large
star-forming region, but also because the nebula's
energetic stars have
blown away
obscuring gas and dust clouds that
would otherwise block
our view - providing an intimate look at a
range of ongoing stages
of
starbirth and evolution.
This detailed image of the
Orion Nebula is the sharpest ever, constructed using data from
the Hubble Space Telescope's Advanced Camera for Surveys
and the European Southern Observatory's
La Silla 2.2 meter telescope.
The mosaic
contains a billion pixels at full resolution
and reveals about 3,000 stars.
In apparent size, the picture is as large as the Full Moon.
At the distance of M42 it spans thirteen light-years.
APOD: 2005 September 18 - M42: Wisps of the Orion Nebula
Explanation:
The Great Nebula in Orion, an immense, nearby
starbirth region,
is probably the most famous of all
astronomical nebulas.
Here, glowing gas surrounds hot young stars at the edge of an
immense interstellar
molecular cloud only 1500
light-years away.
In the above deep image, faint wisps and sheets of
dust and gas are particularly evident.
The Great Nebula in Orion can be found with the
unaided eye just below and to the left of the
easily identifiable
belt of three stars in the popular constellation
Orion.
In addition to housing a bright
open cluster of stars known as the
Trapezium, the
Orion Nebula contains many
stellar nurseries.
These nurseries contain
hydrogen gas, hot young stars,
proplyds, and
stellar jets
spewing material at high speeds.
Also known as
M42, the
Orion Nebula spans about 40 light years and is located in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2005 May 19 - X Ray Stars in the Orion Nebula
Explanation:
When our
middle-aged Sun
was just a few
million years old it was
thousands of times brighter
in
x-rays.
In fact, it was likely similar to some of the stars found
in this false-color x-ray composite of the Orion Nebula region
from the Chandra Observatory.
The image is
centered
on bright stars of the nebula's
Trapezium star cluster, and while
analyzing the
Chandra data
astronomers have now found examples of young,
sun-like stars producing intense
x-ray flares.
It sounds dangerous, but the situation may actually
favor the formation of
hospitable
planetary systems like our own.
Energetic flares can produce turbulence in the
planet-forming disks
surrounding the stars -
preventing rocky earth-like planets from spiraling uncomfortably
close to and even
falling into
their active, young parent stars.
About 1,500 light-years away, the
Orion Nebula is the closest
large stellar nursery.
At that distance, this Chandra image spans about 10 light-years.
APOD: 2005 April 20 - Barnard's Loop Around Orion
Explanation:
Why is the
belt of Orion surrounded by a bubble?
Although glowing like an
emission nebula,
the origin of the bubble, known as
Barnard's Loop, is currently unknown.
Progenitor hypotheses include the
winds
from bright Orion stars and the
supernovas
of stars long gone.
Barnard's Loop is too faint to be identified with the unaided eye.
The nebula
was discovered only in 1895 by
E. E. Barnard on long duration film exposures.
Orion's belt is seen as the
three bright stars across the center of the image,
the upper two noticeably blue.
Just to the right of the
lowest star in Orion's belt is a slight indentation in an
emission nebula that, when seen at
higher magnification, resolves into the
Horsehead Nebula.
To the right of the belt stars is the bright, famous, and photogenic
Orion Nebula.
APOD: 2005 April 19 - Orion in Infrared
Explanation:
Do you recognize the constellation Orion?
This striking but unfamiliar looking picture of the familiar Orion region of the sky was produced using survey data
from the now-defunct
InfraRed Astronomical Satellite (IRAS).
The above image
combines information recorded at three different invisible
infrared wavelengths and covers about 30x24 degrees on the sky.
Most of Orion's visually impressive stars
don't stand out, but bright
Betelgeuse
does appear as a small bright purplish dot on the lower left.
The bright region on the right contains the
Great Nebula in Orion,
while the bright region just above the image bottom is the
Rosette Nebula.
Surrounding these regions
are a jumble of chaotic glowing gas and
dark dust
jettisoned by stars forming and exploding over millions of years.
APOD: 2005 March 21 - Orion's Horsehead Nebula
Explanation:
The Horsehead Nebula
is one of the most famous nebulae on the sky.
It is visible as the dark indentation to the red emission nebula
seen above and to the right of center in the
above photograph.
The bright star on the left is located in the
belt of the familiar constellation of Orion.
The horse-head
feature is dark because it is really an opaque
dust cloud which lies in
front of the bright red emission nebula.
Like clouds in Earth's atmosphere, this cosmic cloud has assumed a
recognizable shape by chance.
After many thousands of years, the internal motions of the cloud
will alter its appearance.
The emission nebula's red color is caused by
electrons recombining with
protons to form
hydrogen atoms.
Also visible in the picture are blue reflection nebulae,
which preferentially
reflect the blue light from
nearby stars.
APOD: 2005 January 6 - UKIRT: Aloha Orion
Explanation:
At the edge of a dense
molecular
cloud, filaments of gas, cosmic dust, and
a multitude of young stars beckon in this penetrating image
of the Orion Nebula.
Alluring structures in the well-known star forming region
are
revealed here in infrared light as viewed
by a new Hawaiian eye - WFCAM - a powerful wide field camera
commissioned at the United Kingdom Infrared Telescope
(UKIRT)
on Mauna Kea.
Only a fraction
of WFCAM's full field, this
picture covers about 11 light-years at the 1,500 light-year
distance of the nebula.
In the image, otherwise invisible
infrared
light has been
mapped into visible colors.
Red represents narrow-band infrared emission from hydrogen
molecules at a wavelength of 2.12
microns,
green is emission at 2.2 microns, and
blue is emission at 1.25 microns.
Visible light has a wavelength of about 0.5 microns
(micrometers).
APOD: 2004 September 27 - The Great Nebula in Orion
Explanation:
The Great Nebula in Orion is a colorful place.
Visible to the unaided eye, it appears as a small
fuzzy patch in the constellation of Orion.
Long exposure, digitally sharpened images like this, however, show the
Orion Nebula to be a busy neighborhood of young stars, hot gas, and dark
dust.
The power behind much of the
Orion Nebula
(M42) is the
Trapezium -
four of the brightest stars in the nebula.
Many of the
filamentary structures visible are actually
shock waves - fronts
where fast moving material encounters slow moving gas.
The Orion Nebula spans about 40 light years and is
located about 1500
light years away in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2004 July 13 - Orion Nebula in Oxygen, Hydrogen, and Sulfur
Explanation:
The Great Nebula in Orion, an
immense, nearby starbirth region,
is arguably the most famous of all astronomical nebulae.
The
Orion Nebula,
also known as M42, is
shown above through
ultraviolet
and blue filters augmented with three exact colors specifically emitted by
hydrogen,
oxygen, and
sulfur.
In addition to housing a bright open cluster of stars known as the
Trapezium, the
Orion Nebula contains many
stellar nurseries.
These nurseries contain glowing gas, hot young stars,
proplyds, and
stellar jets spewing material at high speeds.
Many of the filamentary structures visible in
this image are actually
shock waves - fronts where fast moving material encounters slow moving gas.
The Orion Nebula spans about 40 light years and is located about 1500 light years away in the same
spiral arm of our Galaxy as the Sun.
APOD: 2004 March 25 - An Orion of a Different Color
Explanation:
Look up into the sky tonight, and even with a good telescope
you won't come across a sight quite like this one.
It is a familiar object though, the grand stellar nursery
known as the
Orion Nebula.
But the
striking picture combines
images taken through three separate filters, each designed
to record different
emission lines - light from Sulfur,
Oxygen, and Hydrogen atoms glowing in the
tenuous nebular gas.
At such low
densities, Sulfur and Hydrogen atoms emit red colors
while Oxygen glows green.
To distinguish their contributions in the final image, Sulfur was
assigned to red, Hydrogen to green, and Oxygen to blue,
a color scheme used
in mapped-color images of other astronomical nebulae as well.
While the result is very different from what the eye
might see,
the image is still both beautiful and scientifically valuable,
tracing
elements and conditions within the nearby
star forming region.
APOD: 2004 March 15 - The Orion Nebula from CFHT
Explanation:
Few astronomical sights excite the imagination like the
nearby stellar nursery known as the
Orion Nebula.
The Nebula's glowing gas surrounds hot young stars at
the edge of an immense interstellar
molecular cloud only 1500 light-years away.
The Great Nebula in Orion can be
found with the unaided eye just below and to the left of the
easily identifiable
belt of three stars in the popular constellation Orion.
The above image from the
3.6-meter Canada-France-Hawaii Telescope atop a
dormant volcano in Hawaii brings out
Orion's detail in spectacular fashion.
Buried in the complex nebulosity are the bright stars of the
Trapezium in
Orion's heart, the sweeping lanes of
dark dust that cross the center,
the pervasive red glowing hydrogen gas,
and the
blue tinted dust
that reflects the light of newborn stars.
The whole Orion Nebula cloud complex, which includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: 2004 January 15 - An Orion Deep Field
Explanation:
Adrift 1,500 light-years away in one of
the night sky's
most recognizable
constellations, the glowing
Orion Nebula and the dark
Horsehead Nebula are contrasting
cosmic vistas.
They both appear in this stunning composite digital image
assembled from over 20 hours of data that includes exposures
filtered to record emission from hydrogen
atoms.
The view reveals extensive
nebulosities associated with
the giant Orion Molecular
Cloud
complex, itself hundreds of light-years across.
The magnificent emission region, the
Orion
Nebula (aka M42), lies at the
upper right of the picture.
Immediately to its left are a cluster of
of prominent bluish
reflection nebulae sometimes called
the Running Man.
The Horsehead
nebula appears as a dark cloud, a small silhouette
notched against the long red glow at the lower left.
Alnitak is the easternmost star in Orion's belt and
is seen as the brightest star to the left of the Horsehead.
Below Alnitak is the
Flame Nebula, with clouds of
bright emission and dramatic dark dust lanes.
Fainter tendrils of glowing hydrogen gas are easily traced
throughout the region in
this
Orion deep field.
APOD: 2003 February 25 - M42: Wisps of the Orion Nebula
Explanation:
The Great Nebula in Orion, an immense, nearby
starbirth region,
is probably the most famous of all
astronomical nebulas.
Here, glowing gas surrounds hot young stars at the edge of an
immense interstellar
molecular cloud only 1500
light-years away.
In the above deep image, faint wisps and sheets of
dust and gas are particularly evident.
The Great Nebula in Orion can be found with the
unaided eye just below and to the left of the
easily identifiable
belt of three stars in the popular constellation
Orion.
In addition to housing a bright
open cluster of stars known as the
Trapezium, the
Orion Nebula contains many
stellar nurseries.
These nurseries contain
hydrogen gas, hot young stars,
proplyds, and
stellar jets
spewing material at high speeds.
Also known as
M42, the
Orion Nebula spans about 40 light years and is located in the same
spiral arm of
our Galaxy as the
Sun.
APOD: 2003 February 7 - Orion on Film
Explanation:
Orion, the Hunter, is one of the most easily recognizable
constellations
in planet Earth's night sky.
But Orion's stars and
nebulae don't look
quite as colorful to the
eye as they do in
this lovely photograph, taken last month from Vekol Ranch south
of
Phoenix, Arizona, USA.
The celestial scene was recorded
in a five minute
time exposure using high-speed color print film
and a 35mm camera mounted on a small telescope.
In the picture, cool red giant
Betelgeuse
takes on a yellowish tint as the brightest star
at the upper left.
Otherwise Orion's hot blue stars are numerous, with
supergiant Rigel balancing Betelgeuse at the
lower right, Bellatrix at the upper right, and
Saiph at the lower left.
Lined up in Orion's belt (left to right) are
Alnitak, Alnilam, and Mintaka all about 1,500 light-years away,
born of the constellation's well studied
interstellar
clouds.
And if the middle "star" of Orion's sword looks reddish and fuzzy
to you, it should.
It's the stellar nursery known as the
Great Nebula of Orion.
APOD: 2003 January 29 - Orion's Horsehead Nebula
Explanation:
The Horsehead Nebula
is one of the most famous nebulae on the sky.
It is visible as the dark indentation to the red emission nebula
seen above and to the right of center in the
above photograph.
The bright star on the left is located in the
belt of the familiar constellation of Orion.
The
horse-head
feature is dark because it is really an opaque
dust cloud which lies in
front of the bright red emission nebula.
Like clouds in Earth's atmosphere,
this cosmic cloud has assumed a recognizable shape by chance.
After many thousands of years, the internal motions of the cloud
will alter its appearance.
The emission nebula's red color is caused by
electrons recombining with
protons to form
hydrogen atoms.
Also visible in the picture are blue reflection nebulae,
which preferentially
reflect the blue light from
nearby stars.
APOD: 2003 January 21 - The Reflecting Dust Clouds of Orion
Explanation:
In the vast
Orion Molecular Cloud complex,
several bright blue nebulas are particularly apparent.
Pictured above are two of the most prominent
reflection nebulas -
dust clouds lit by the
reflecting light of bright embedded stars.
The more famous nebula is
M78,
on the upper right, cataloged over 200 years ago.
On the lower left is the lesser known
NGC 2071.
Astronomers continue to
study these
reflection nebulas to better understand how interior stars form.
The Orion complex
lies about 1500 light-years distant, contains the
Orion and
Horsehead nebulas,
and covers much of the
constellation of Orion.
APOD: 2002 December 25 - Orion Rising
Explanation:
Orion
always comes up sideways ... and was caught in the
act earlier this month by astronomer Jimmy Westlake,
stargazing eastward over the Rocky Mountains north of
Leadville, Colorado, USA.
To make this gorgeous image,
Westlake placed his camera on a tripod for two exposures.
The first lasted for 18 minutes allowing the
stars to trail as
they rose above the mountain range.
After a minute long pause, the second exposure began and
lasted only 25 seconds
decorating the end of each trail with a celestial point
of light.
The three bright stars in Orion's belt stand in a nearly
vertical line above the mountain peak right of center.
Hanging from his belt, the stars and
nebulae
of the Hunter's sword follow the slope down and to the right.
A festive yellow-orange Betelgeuse
is the brightest star above the
peak just left of center, but brighter still, planet
Saturn shines near the upper left corner.
In the foreground on planet Earth, a frozen lake and snowy
mountains are lit by a four day old crescent Moon.
Happy Holidays and Best Wishes from
APOD!
APOD: 2002 December 20 - Colorful Clouds of Orion
Explanation:
Revisiting one of the most
famous nebulae in
planet Earth's night sky,
astrophotographer
Robert Gendler has constructed this stunning,
color-enhanced mosaic
of the region surrounding the
Great
Nebula in Orion.
As seen here, the
clouds of Orion are dominated by the
reddish emission nebula M42
near the bottom of the image,
with blue reflection nebulae, including
NGC 1977, near the top.
Strewn with dust lanes and dark nebulae,
the striking cosmic apparitions
surrounding Orion's
stellar nurseries are about 1,500 light-years away and are
themselves several light-years across.
Located at the edge of a giant molecular
cloud complex
spanning hundreds of light-years, these nebulae represent only a small,
but very visible(!), fraction of this region's wealth of
interstellar
material.
Within these colorful clouds of Orion,
astronomers have also
identified what appear to be numerous
infant solar systems.
APOD: 2002 May 30 - Orion Nebulosities
Explanation:
Adrift 1,500 light-years away in one of the night sky's
most recognizable
constellations, the glowing
Orion Nebula and the dark
Horsehead Nebula are contrasting
cosmic vistas.
They both appear in this stunning composite color photograph along with
other nebulosities as part
of the giant Orion Molecular
Cloud
complex, itself hundreds of light-years across.
The magnificent
Orion
Nebula (aka M42) lies at the
bottom of the image.
This emission nebula's
bright central regions were
captured on fast film in a relatively short 30 second exposure.
Above M42
are a cluster of prominent bluish
reflection nebulae
and fainter reddish emission nebulae recorded in additional exposures
lasting up to 40 minutes.
The Horsehead
appears as a dark nebula, a small silhouette
notched against the long red glow at the upper left.
Alnitak is the easternmost star in Orion's belt and
is seen as the brightest star above the Horsehead.
Immediately to Alnitak's left is the
Flame Nebula, with clouds of
bright emission and dramatic dark dust lanes.
The telescopic
exposures were made from a site in the Southern French Alps
at an altitude of 2,800 meters (a little closer to the stars!)
in September of 2001.
APOD: 2002 April 20 - Orion Nebula: The 2MASS View
Explanation:
Few astronomical sights excite the imagination like the nearby
stellar nursery known as
the Orion Nebula.
The Nebula's glowing gas surrounds hot young stars at the edge of an
immense interstellar molecular cloud only 1,500 light-years away.
This
distinctively detailed image of the Orion Nebula was constructed
using data from the
2 Micron All Sky Survey or 2MASS.
Using
telescopes in the Northern and Southern Hemispheres of
planet Earth,
the
2MASS project has mapped the entire
sky in infrared light.
The wavelength of infrared light is longer than visible light but more
easily penetrates obscuring dust clouds.
2MASS cameras were sensitve to near infrared wavelengths
around 2 microns or about 0.00008 inches.
Visible light has a wavelength of about 0.00002 inches.
Survey
observations in three infrared bands were translated to blue,
green, and red colors to produce this composite image.
APOD: 2002 February 13 - The Great Nebula in Orion
Explanation:
Few astronomical sights excite the imagination like the
nearby stellar nursery known as the
Orion Nebula.
The Nebula's glowing gas surrounds hot young stars at
the edge of an immense interstellar
molecular cloud only 1500 light-years away.
The Great Nebula in Orion can be
found with the unaided eye just below and to the left of the
easily identifiable
belt of three stars in the popular constellation Orion.
The above image has been contrast balanced to bring out Orion's detail
in spectacular fashion.
Visible simultaneously are the bright stars of the
Trapezium in
Orion's heart, the sweeping lanes of
dark dust that cross the center,
the pervasive red glowing hydrogen gas,
and the
blue tinted dust
that reflects the light of newborn stars.
The whole Orion Nebula cloud complex, which includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: 2001 July 22 - NGC 1977: Blue Reflection Nebula in Orion
Explanation:
The
Orion Nebula
is visible to the unaided eye as a fuzzy patch near the famous
belt of three stars in the Orion.
The above picture captures a part of the
Orion Nebula that primarily reflects light from bright
Orion stars.
This
reflection nebula
appears blue because the blue light from the neighboring stars
scatters more efficiently from
nebula gas than does red light.
The dark lanes are composed of mostly
interstellar dust - fine needle-shaped
carbon grains.
APOD: 2001 May 4 - Protoplanetary Survivors in Orion
Explanation:
The
Orion Nebula is a nuturing stellar nursery filled with
hot young stars and their natal clouds of gas and dust.
But for planetary
systems, the active star-forming region can present
a hazardous and inhospitable birthplace.
While the formation of dusty
protoplanetary disks seems
common in Orion, these
Hubble Space Telescope close-up images dramatically reveal
the torturous conditions they must face while trying to grow into
full-fledged planetary systems.
In each case,
a central young star is surrounded by a
disk substantially wider than our solar system.
The disks likely contain material in the process of planet formation.
However, withering ultraviolet radiation from one of Orion's
nearby hot stars is rapidly destroying the disks --
ultimately creating the comet-shaped clouds of glowing gas
seen engulfing the protoplanetary systems.
Planet formation must occur
quickly here, if at all.
Researchers estimate
that about 90 percent of Orion's youngest
protoplanetary disks will not survive the next 100,000 years.
APOD: 2001 January 30 - The Orion Nebula from VLT
Explanation:
The Great Nebula in Orion is a colorful place.
Visible to the unaided eye, it appears as a small
fuzzy patch in the
constellation of Orion.
But
this image, a representative-color composite of 81
near-infrared light images taken with
VLT's ISAAC, shows the
Orion Nebula to be a busy neighborhood of
young stars, hot gas, and dark dust.
The power behind much of the
Orion Nebula (M42) is the
Trapezium -
four of the brightest stars in the nebula.
The eerie blue glow surrounding the
bright stars pictured here is their own
starlight reflected by nearby
dust.
Dark brown
dust filaments
cover much of the region.
The whole
Orion Nebula cloud complex, which
includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: 2000 November 22 - The Orion Nebula in Hydrogen
Explanation:
The
Great Nebula in Orion can be found just below
and to the left of the easily identifiable
belt of three stars in the popular
constellation Orion.
This fuzzy patch,
visible to the unaided eye,
contains one of the closest
stellar nurseries, lying at a distance of about 1500
light years.
The
above picture highlights red light emitted
by the nebula's hydrogen gas.
Dark
dust
filaments punctuate regions of this glowing hydrogen
gas and reflect light from the
nebula's brightest stars.
Recent observations of the
Orion Nebula by the
Hubble Space Telescope
have located
solar-system sized regions that are
thought to be planet-forming circumstellar disks.
APOD: 2000 November 20 - A 2000 Leonid Through Orion
Explanation:
The Leonid Meteor Shower this year could be
described as good but not great.
During November 17 and 18 the Earth crossed
through several streams of
sand-sized grit
left orbiting the Sun by
Comet Tempel-Tuttle.
Several distinct peaks in
meteor activity were reported,
with rates approaching 400 meteors per hour
for brief periods for some dark locations.
Pictured above, a
Leonid meteor was caught from
Florida
streaking through the
constellation of Orion
on the morning of 2000 November 18.
Visible as a red-tinged smudge to the left of the
three nearly linear stars that compose
Orion's belt is the picturesque star-forming region known as the
Orion Nebula.
Next year, the
Leonids Meteor Shower is expected
by many to be much more active.
APOD: 2000 August 27 - Orion's Horsehead Nebula
Explanation:
The Horsehead Nebula
is one of the most famous nebulae on the sky.
It is visible as the black indentation to the red emission nebula
seen just to the right of center of the above photograph.
The bright star near the center is located in the
belt of the familiar constellation of Orion.
The
horse-head
feature is dark because it is really an opaque
dust cloud which lies in
front of the bright red emission nebula.
Like clouds in Earth's atmosphere,
this cosmic cloud has assumed a recognizable shape by chance.
After many thousands of years, the internal motions of the cloud
will alter its appearance.
The emission nebula's red color is caused by
electrons recombining with
protons to form
hydrogen atoms.
Also visible in the picture are blue reflection nebulae,
which preferentially
reflect the blue light from
nearby stars.
APOD: 2000 May 6 - The Heart Of Orion
Explanation:
Newborn stars lie at
at the heart
of the
the Orion Nebula,
hidden from view by the dust and gas of the giant Orion
Molecular Cloud number 1
(OMC-1).
Sensitive to invisible
infrared
wavelengths, Hubble's NICMOS camera
can explore the
interior of OMC-1 detecting the infrared radiation from
infant star clusters and
the interstellar dust and atoms energized by their intense starlight.
In this false color picture,
stars and the glowing dust clouds which also scatter the starlight appear
yellowish orange while emission from hydrogen gas is blue.
The dramatic image reveals a wealth of details, including
many filaments and arcs of gas and dust
-- evidence of violent motions stirred-up by the emerging stars.
The bright object near the center is the massive young star "BN"
(named for its discoverers Becklin and Neugebauer).
The pattern of speckles and
ripples surrounding BN and other bright stars are image artifacts.
APOD: 2000 March 31 - Free Floating Planets In Orion
Explanation:
This false-colour image
of the young Trapezium star cluster in the Orion
Nebula was made with an
infrared camera at wavelengths about
twice as long as visible light.
The infrared data are part of a sensitive survey
of this nearby star forming region in which
astronomers
have identified over 100 extremely low mass
objects -- candidates for
elusive brown dwarf stars.
Brown dwarfs are failed
stars with masses so low (about 8% of the Sun's)
that they can not sustain nuclear hydrogen burning, a sun-like star's main
energy source.
While brown dwarfs are thought to be still massive enough to burn
deuterium for energy,
thirteen of the low mass objects show evidence of
lying below even the deuterium burning limit
(about 1.3% of the
Sun's mass) falling in a range
more commensurate with giant planets.
These drifting, "free-floating planets" are perhaps as little as 8
times as massive as
Jupiter and likely formed along with the cluster stars
a million or so years ago.
They are detectable in the infrared because they
are still hot from formation, but will eventually cool and fade.
If the Trapezium is typical of young
star clusters, then
the survey results suggest that brown dwarfs
and free-floating planets may be fairly common, but there
are not enough to solve the mystery
of dark
matter in the Universe.
APOD: 2000 March 13 - A Panorama of Oddities in Orion A
Explanation:
New stars, fast jets, and shocked gas clouds
all occupy Orion A, a
giant molecular cloud
just south of the
Orion Nebula.
The bright object visible below and slightly left of center of
this recently released picture is the
reflection nebula
NGC 1999.
Wind from NGC 1999's
central star, V380 Orionis, appears to have created the
surrounding billows of red and brown gas.
Several bright young stars illuminate reflecting
dust at the top right of the image.
Jets shoot from dozens of young stars creating glowing
compressed shocked waves known
Herbig-Haro objects.
One such shock is the unusual
Waterfall,
the bright streak on the upper right,
which is a source of unusual
radio waves.
The cone-shaped shock to the Waterfall's
lower right may result from a jet emitted
HH1 and HH2, located 10
light-years away below NGC 1999.
The unusual and energetic oddities that
occur and interact in
star forming regions
are often as complex as they are beautiful.
APOD: 2000 March 2 - NGC 1999: Reflection Nebula In Orion
Explanation:
A dusty bright nebula
contrasts dramatically with a dusty dark nebula in
this Hubble Space Telescope image recorded shortly
after December's orbital
servicing mission.
The nebula, cataloged as
NGC 1999, is a
reflection nebula,
which shines by reflecting light from
a nearby star.
Unlike emission nebulae, whose
reddish glow comes from
excited atoms of gas, reflection nebulae have a
bluish cast
as their interstellar dust
grains preferentially reflect blue
starlight.
While perhaps the most famous reflection nebulae surround
the bright young stars of the Pleiades
star cluster,
NGC 1999's stellar illumination is provided by the embedded variable star
V380
Orionis, seen here just left of center.
Extending right of center, the ominous
dark nebula is actually a condensation of cold molecular
gas and dust so thick and dense that it blocks light.
From our perspective it lies in front of the bright
nebula, silhouetted against the ghostly nebular glow.
New stars will likely form within
the dark cloud, called a Bok globule,
as self-gravity continues to compress its dense gas and dust.
Reflection nebula
NGC 1999
lies about 1500 light-years away in the constellation
Orion,
just south of Orion's well known emission nebula,
M42.
APOD: 2000 February 4 - X-Ray Stars Of Orion
Explanation:
The stars of Orion shine brightly
in northern winter skies where
the constellation
harbors the closest large stellar nursery,
the Great Nebula of Orion, a mere 1500 light-years away.
In fact, the apparently bright clump of stars near the center
of this Chandra
X-ray telescope picture of a portion of
the nebula are the massive stars of
the Trapezium - the
young star cluster which powers much of the nebula's
visible-light glow.
But the sheer number of other stars seen in
this X-ray image, which
spans about 10 light-years, has surprised and delighted astronomers
and
this picture was recently touted
as the richest field of X-ray sources ever recorded
in a single observation.
The picture does dramatically illustrate that
young stars are prodigious sources
of X-rays,
thought to be produced in hot
stellar coronas and
surface flares in a young star's strong magnetic field.
Our middle-aged Sun
itself was probably thousands of times
brighter in X-rays when, like
the Trapezium stars, it was
only a few million years old.
The dark lines through the image are instrumental artifacts.
APOD: September 24, 1999 - Cometary Globules In Orion
Explanation:
Intense
ultraviolet light from massive, hot stars in
the Orion region has sculpted and
compressed clouds of dust and gas in to
distinctively shaped Cometary Globules.
Seen in this IRAS
infrared image recorded at
a wavelength sensitive to emission from dust, the
elongated globules are easily visible along
with a bright region which corresponds to the
Trapezium star cluster.
Otherwise known as
the Witch Head Nebula,
IC 2118 is the string of globules near the middle right.
Suggestively similar to comets in general appearance only,
Cometary Globules
are interstellar condensations on a vastly
different scale.
These are likely related to star formation episodes in
the Orion
molecular cloud.
Besides those indicated by the arrows,
more comet-shaped clouds or globules are present in this image.
APOD: September 14, 1999 - The Colorful Orion Nebula
Explanation:
The Great Nebula in Orion is a colorful place.
Visible to the unaided eye as a
fuzzy patch in the
constellation of Orion,
this image
taken with the
Big Throughput Camera shows the
Orion Nebula to be a busy neighborhood of
young stars, hot gas, and dark dust.
The power behind much of the
Orion Nebula (M42) is the
Trapezium -
four of the brightest stars in the nebula.
The eerie blue glow surrounding the
bright stars pictured here is their own
starlight reflected by nearby
dust.
Hot oxygen and
hydrogen gases cause the
extended green and pink glows, respectively.
Dark brown
dust filaments
cover much of the region.
The whole
Orion Nebula cloud complex, which
includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
APOD: May 22, 1999 - M42: A Mosaic of Orion's Great Nebula
Explanation:
The Great Nebula in Orion,
an immense, nearby starbirth region, is
probably the most famous of all astronomical nebulae.
Here, 15 pictures from the
Hubble Space Telescope have been mosaicked
to cover the inner 2.5 light years of the nebula and illustrate
its diverse nature.
In addition to housing a bright open cluster of
stars known as the Trapezium, the Orion Nebula contains many
stellar nurseries.
These nurseries contain
hydrogen gas,
hot young stars,
proplyds, and stellar
jets spewing material at high speeds.
Most of the filamentary structures visible in this image are
actually shock waves -
fronts where fast moving material encounters slow moving gas.
Shocks are particularly apparent near the bright stars in the
lower left of the picture.
The Orion Nebula
is about 1500 light years distant, located in the same spiral arm of
our Galaxy as the
Sun.
APOD: March 20, 1999 - Aurora and Orion
Explanation:
Looking toward the south from low Earth orbit, the crew of the
Space Shuttle Endeavor made this stunning time exposure of the
Aurora Australis or southern lights in April of 1994.
Aurora are visible at high
northern latitudes as well, with the northern lights
known as
Aurora Borealis.
They are caused by high energy electrons from the
Solar Wind
which are funneled into the atmosphere near the poles
by the
Earth's magnetic field.
The reddish colors occur at the highest altitudes (about 200 miles)
where the air is least dense. At lower altitudes and greater densities
green tends to dominate ranging to a pinkish glow at the lowest.
The familiar constellation of
Orion the Hunter is clearly
visible above the dark horizon in the background.
Because of the shuttle's orbital motion, the bright stars in
Orion appear slightly elongated.
APOD: February 2, 1999 - The Orion Nebula from Subaru
Explanation:
The Orion Nebula (M42) shows a host of treasures when viewed in
infrared light.
Some stars in the
Trapezium, an
open cluster
of stars at the center, are only visible in infrared light.
The orange feature above center is called the Kleinman-Low Nebula,
and appears greatly affected by newly forming central star IRc2.
The blue emission in this representative color photograph
is caused by hot gas ionized by the
Trapezium stars.
This is one of the
first photographs ever taken through Japan's new
Subaru Telescope.
APOD: January 15, 1999 - Reflections Of Orion
Explanation:
The Orion Nebula and
its surroundings present skygazers with a
wondrous jumble of newborn stars, gas, and dust.
Emission nebulae - glowing energized clouds of gas, and
reflection nebulae - dust clouds
shining by reflected starlight, abound at this
photogenic
cosmic location a mere 1,500 light-years or so away.
This telescopic image reveals an
intriguing nebulosity which seems to consist of dust clouds
illuminated not by starlight but by the light of the
Orion Nebula itself.
In non-telescopic views, the bright group of stars near the top
appear as the northernmost star in Orion's sword.
They are seen here illuminating the nearby dust clouds.
Yet the yellowish streamers of dust across the middle reflect
the light of the Orion Nebula,
which lies just off the bottom edge of the photo.
APOD: January 3, 1999 - Orion's Horsehead Nebula
Explanation:
The Horsehead Nebula
is one of the most famous nebulae on the sky. It is visible
as the black indentation to the red emission nebula
seen just to the right of center of the above photograph. The
bright star near the center is located in the belt of the familiar
constellation of Orion.
The horse-head feature is dark because it is really an opaque
dust cloud which lies in
front of the bright red emission nebula.
Like clouds in Earth's atmosphere,
this cosmic cloud has assumed a recognizable shape by chance.
After many thousands of years, the internal motions of the cloud
will alter its appearance. The emission nebula's
red color is caused by electrons recombining with protons to form
hydrogen atoms. Also
visible in the picture are blue reflection nebulae,
which preferentially
reflect the blue light from nearby stars.
APOD: August 29, 1998 - Orion Star Colours
Explanation:
What determines a star's colour?
Its temperature.
Red stars are cool, around 3,000
kelvins (K), while blue stars are hotter and can
have temperatures over 30,000 K.
Our own lovely yellow Sun's temperature is a
comforting 6,000 K.
Differences in star colours are dramatically
illustrated in the above photo of
the constellation Orion,
made using a "star trail step-focus" technique.
In this technique, a time exposure is used to create
star trails,
but during the exposure, the focus is changed in steps.
For the brighter stars, the blurred image
produces more saturated colours in photographs.
At the upper left,
the cool red supergiant Betelgeuse
stands out from the other, hotter, bluish stars composing
the body of the constellation.
Bright
Rigel, a blue supergiant, is at the lower right.
APOD: July 31, 1998 - IRAS Orion
Explanation:
Do you recognize the
constellation Orion?
This striking but unfamiliar looking picture of
the familiar
Orion region of the sky was produced
using survey data from the
InfraRed Astronomical Satellite (IRAS).
It combines information recorded
at three different
invisible infrared wavelengths
in a red, green, and blue color scheme
and covers about 30x24 degrees on the sky.
Most of Orion's visually impressive stars don't stand out,
but bright Betelgeuse
does appear as a small purplish dot just above center.
Immediately to the right of Betelgeuse and prominent in the IRAS
skyview,
expanding debris from a stellar explosion,
a supernova remnant,
is seen as a large bright ring-shaped feature.
The famous
gas clouds
in Orion's sword glow brightly as the yellow
regions at the lower right.
No longer operational,
IRAS used a telescope cooled by liquid
helium to detect
celestial infrared radiation.
APOD: June 12, 1998 - Orion Nebula: The 2MASS View
Explanation:
Few astronomical sights excite the imagination like the nearby
stellar nursery known as
the Orion Nebula.
The Nebula's glowing gas surrounds hot young stars at the edge of an
immense interstellar molecular cloud only 1,500 light-years away.
This distinctively detailed image of the Orion Nebula was constructed
using data from the
2 Micron All Sky Survey or 2MASS.
Now underway with
telescopes in the Northern and Southern Hemispheres of
planet Earth,
the 2MASS project will map the entire
sky in infrared light.
The wavelength of infrared light is longer than visible light but more
easily penetrates obscuring dust clouds.
2MASS cameras are sensitve to near infrared wavelengths
around 2 microns or about 0.00008 inches.
Visible light has a wavelength of about 0.00002 inches.
Survey observations in three infrared bands were translated to blue,
green, and red colors to produce this composite image.
APOD: June 4, 1998 - Comet SOHO and Nebulae in Orion
Explanation:
Astrophotographer Michael Horn
captured this
gorgeous view of
comet SOHO in the dark night sky above
Wandibindle, Queensland, Australia on May 23rd.
On this date,
comet SOHO
was moving against the background of
the nebula-rich constellation of Orion.
South is up in the
picture which shows SOHO's bright head or
coma and long
tail extending past
the glowing gas clouds and dark dust lanes of
the Flame and
Horsehead nebulae.
Alnitak, the bright star above and to the right of the
cometary coma, is also known as Zeta Orionis,
the eastern-most of the three stars in
Orion's belt.
Southern Hemisphere
observers report that comet SOHO has recently
undergone a dramatic increase in brightness.
APOD: April 21, 1998 - Water From Orion
Explanation:
Is Orion all wet?
Recent observations have confirmed
that water molecules now exist in the famous
Orion Nebula,
and are still forming.
The
Orion Nebula (M42, shown above) is known to be composed mostly of
hydrogen gas, with
all other atoms and molecules being comparatively
rare. The nebula is so
vast, though, that even the measured
minuscule production rate creates enough water to fill
Earth's oceans 60 times over every day,
speculate discoverers led by M. Harwit
(Cornell).
The water that composes
comets, the oceans of Earth, and even humans may have been created in a cloud like the Orion Nebula.
APOD: February 1, 1998 - NGC 1977: Blue Reflection Nebula in Orion
Explanation:
The
Orion Nebula
is visible to the unaided eye as a fuzzy patch near the famous
belt of three stars in the
constellation
Orion. The
above picture captures a part of the
Orion Nebula that primarily reflects light from bright Orion stars. This
reflection nebula appears blue
because the blue light from the neighboring stars scatters more
efficiently from nebula gas than does red light.
The dark lanes are composed of mostly
interstellar dust - fine needle-shaped
carbon grains.
APOD: January 27, 1998 - The Great Nebula in Orion
Explanation:
The Great Nebula in Orion can be found just below and to
the left of the easily identifiable
belt of three stars in the popular constellation Orion.
This fuzzy patch contains one of the closest stellar nurseries,
lying at a distance of about 1500 light years.
In the above picture, the red region on the left consists of nebulae designated
M42 and M43 and contains the bright
Trapezium
open cluster.
The blue region on the right is a nebula
primarily
reflecting
the light from internal bright stars.
Recent observations of the
Orion Nebula by the
Hubble Space Telescope
have located solar-system sized
star-forming regions.
APOD: December 1, 1997 - Orion: The Big Picture
Explanation:
Orion is big. Some of the stars that form the constellation of Orion are part of a giant gas cloud
complex that stretches over 100 light years and
appears more than 50 times the diameter of the Moon.
Components of this cloud include the
Horsehead Nebula, the
Orion Nebula, the
Trapezium
open cluster, and
small disks
containing stellar systems which are just forming.
At 1500 light years,
Orion is the closest star forming region to Earth.
Close inspection of the photo's center should reveal the
three stars which form the
belt of Orion.
APOD: May 23, 1997 - The Heart Of Orion
Explanation:
Newborn stars lie at the heart of
the Orion Nebula,
hidden from view by the dust and gas of the giant Orion
Molecular Cloud number 1
(OMC-1).
Sensitive to invisible
infrared wavelengths,
Hubble's recently installed NICMOS camera
can explore
the interior of OMC-1 detecting the infrared radiation from
infant star clusters and
the interstellar dust and atoms energized by their intense starlight.
In this false color picture,
stars and the glowing dust clouds which also scatter the starlight appear
yellowish orange while emission from hydrogen gas is blue.
The dramatic image reveals a wealth of details, including
many filaments and arcs of gas and dust
-- evidence of violent motions stirred-up by the emerging stars.
The bright object near the center is the massive young star "BN"
(named for its discoverers Becklin and Neugebauer).
The pattern of speckles and
ripples surrounding BN and other bright stars are image artifacts.
APOD: May 11, 1997 - M42: A Mosaic of Orion's Great Nebula
Explanation:
The Great Nebula in Orion,
an immense, nearby starbirth region, is
probably the most famous of all astronomical nebulae.
Here, 15 pictures from the
Hubble Space Telescope have been mosaicked
to cover the inner 2.5 light years of the nebula and illustrate
its diverse nature.
In addition to housing a bright open cluster of
stars known as the Trapezium, the Orion Nebula contains many
stellar nurseries.
These nurseries contain
hydrogen gas,
hot young stars,
proplyds, and stellar
jets spewing material at high speeds.
Most of the filamentary structures visible in this image are
actually shock waves -
fronts where fast moving material encounters slow moving gas.
Shocks are particularly apparent near the bright stars in the
lower left of the picture.
The Orion Nebula
is about 1500 light years distant, located in the same spiral arm of
our Galaxy as the
Sun.
APOD: April 29, 1997 - Hale-Bopp and Orion
Explanation:
Comet Hale-Bopp is still brighter than most
constellations.
In fact,
Comet Hale-Bopp may now hold the record for
staying
bright the longest. Last week the comet was
photographed above
in the same field as the constellation
Orion, visible in the
photograph's center, as well as with
Sirius, the brightest star in the night,
visible on the far left. Just below
Comet Hale-Bopp
on the right is the
volcanic
caldera known as White Mountain.. As the comet heads south, it has become
visible
to most of the world, now including many observers in the
Earth's Southern Hemisphere.
APOD: January 26, 1997 - Aurora and Orion
Explanation:
Looking toward the south from low Earth orbit, the crew of the
Space Shuttle Endeavor made this stunning time exposure of the
Aurora Australis or southern lights in April of 1994.
Aurora are visible at
high northern latitudes as well, with the northern lights
known as Aurora Borealis.
They are caused by high energy electrons from the
Solar Wind
which are funneled into the atmosphere near the poles
by the
Earth's magnetic field.
The reddish colors occur at the highest altitudes (about 200 miles)
where the air is least dense. At lower altitudes and greater densities
green tends to dominate ranging to a pinkish glow at the lowest.
The familiar constellation of
Orion the Hunter is clearly
visible above the dark horizon in the background.
Because of the shuttle's orbital motion, the bright stars in
Orion appear slightly elongated.
APOD: December 7, 1996 - Planetary Systems Now Forming in Orion
Explanation: How do planets form? Astronomers are finding
out by studying one of the most interesting of all astronomical
nebulae known, the Great Nebula in Orion.
Insets to above mosaic
show several planetary systems in
formation. The bottom left insert shows the relative size of
our own Solar System. The Orion Nebula
contains many stellar nurseries. These nurseries contain hydrogen
gas, hot young stars, proplyds, and
stellar jets spewing material at
high speeds. Much of the filamentary structure visible in this
image are actually shock waves
- fronts where fast moving material encounters slow moving gas.
Some shock waves are visible near one of the bright stars in the
lower left of the picture. The Orion Nebula
is located in the same spiral arm of our Galaxy
as is our Sun.
APOD: December 2, 1996 - Orion's Star Colors
Explanation:
What determines a star's color?
Its temperature. Red stars are cool, with
temperatures of around 3,000
kelvins (K), while blue stars are hotter and can
have temperatures over 30,000 degrees K.
Our own lovely yellow Sun's temperature is a
comforting 6,000 K.
Differences in star colors are dramatically
illustrated in the above photo of
the constellation Orion,
made using a "star trail step-focus" technique.
In this technique, a time exposure is used to create
star trails,
but during the exposure, the focus is changed in steps.
For the brighter stars, the blurred image
produces more saturated colors in photographs.
At the upper left,
the cool red supergiant Betelgeuse
stands out from the other, hotter, bluish stars composing
the body of the constellation.
Bright
Rigel, a blue supergiant, is at the lower right.
APOD: October 2, 1996 - Orion's Horsehead Nebula
Explanation: The Horsehead Nebula
is arguably the most famous nebula on the sky. It is visible
as the black indentation to the red emission nebula
seen just to the right of center of the above photograph. The
bright star near the center is located in the belt of the familiar
constellation of Orion.
The horse-head feature is dark because it is really an opaque
dust cloud which lies in
front of the bright red emission nebula.
Like clouds in Earth's atmosphere,
this cosmic cloud has assumed a recognizable shape by chance.
After many thousands of years, the internal motions of the cloud
will alter its appearance. The emission nebula's
red color is caused by electrons recombining with protons to form
hydrogen atoms. Also
visible in the picture are blue reflection nebulae,
which preferentially reflect the blue light from nearby stars.
APOD: April 18, 1996 - Hyakutake, Venus, Orion, and Pond
Explanation:
Can you find
Comet
Hyakutake in the above picture? In this gorgeous
photo, the starry
night sky of April 9th is pictured with its new comet visitor.
In the foreground is a pond
with the lights of Kansas City, Missouri on the western horizon.
On the upper left, the constellation of
Orion is visible.
At the center, the
brightest object in the picture is the
planet Venus. Venus's reflection
can be seen in the pond. On the right - halfway between Venus and the
photograph's edge - can be seen two bright objects fairly close to each
other. Of these two, look closely at lower right object. See the tail?
Comet Hyakutake is
still visible for Northern observers
in the Western sky and now has begun to
brighten again as it nears the Sun.
APOD: March 20, 1996 - NGC 1977: Blue Reflection Nebula in Orion
Explanation:
The
Orion
Nebula is visible to the unaided eye as a fuzzy patch near the
famous belt of three stars in the
constellation Orion. The above picture
captures a part of the
Orion Nebula that primarily reflects light from
bright Orion stars. This
reflection nebula
appears blue because the blue light from the neighboring stars scatters
more efficiently from nebula gas than does red light. The dark lanes are
composed of mostly
interstellar dust
- fine needle-shaped carbon grains.
APOD: November 21, 1995 - M42: Orion Nebula Mosaic
Explanation:
The Great Nebula in
Orion is one of the most interesting of all astronomical nebulae known.
Here fifteen
pictures from the
Hubble Space Telescope have been merged to show
the great expanse and diverse nature of the nebula. In addition to housing
a bright
open cluster of stars known as the
Trapezium, the Orion Nebula contains many
stellar nurseries. These nurseries contain
hydrogen gas,
hot young stars,
proplyds, and stellar
jets spewing material at high speeds. Much of
the filamentary structure visible in this image are actually shock waves -
fronts where fast moving material encounters slow moving gas. Some shock
waves are visible near one of the bright stars in the lower left of the
picture. The
Orion Nebula is located in the same spiral arm of
our Galaxy as is our
Sun. It takes light about 1500 years to
reach us from there.
APOD: November 14, 1995 - Aurora and Orion
Explanation:
Looking toward the south from low Earth orbit, the crew of the
Space Shuttle Endeavor made this stunning time exposure of the
Aurora Australis (southern lights) in April of 1994.
The aurora
are caused by high energy electrons from the
Solar Wind
which are funneled into the atmosphere
by the
Earth's magnetic field.
The reddish colors occur at the highest altitudes (about 200 miles)
where the air is least dense. At lower altitudes and greater densities
green tends to dominate. At the lowest altitudes a pinkish glow is
sometimes produced.
The familiar
constellation of Orion the Hunter is clearly
visible above the dark horizon in the background.
Because of the shuttle's orbital motion, the bright stars
in
Orion appear slightly elongated.
APOD: September 25, 1995 - Orion's Horsehead Nebula
Explanation:
The black indentation to the red
emission nebula
seen just to the right of
center of the above photograph is one of the most famous features in any
nebulae on the sky. Because of its shape, it is known as the
Horsehead
Nebula. The bright star near the center is
located in the belt of the familiar constellation of Orion.
The horse head feature is dark because it is really a dense
dust cloud which lies
in front of the bright nebula and blocks the light.
Like clouds in our sky, this cosmic cloud has chanced to assume
a recognizable shape. After thousands of years, the
internal motions of the cloud will alter its appearance.
The emission nebula's
red color is caused by electrons recombining with protons to form
hydrogen atoms.
Also visible in the picture are blue
reflection nebulae.
This type of nebula contains dust which
preferentially reflects the blue light of nearby stars.
APOD: July 3, 1995 - The Great Nebula in Orion
Explanation:
The Great Nebula in Orion, M42, can be found on the night sky just below and
to the left of the easily identifiable belt of three stars in the popular
constellation Orion. This nebula is one of the closest stellar nurseries -
where young stars are being formed even now.
Clumps of gas (mostly hydrogen and helium) and dust in the nebula
are squeezed together by their own gravity until they collapse and
form stars.
Some stars we can see here partially obscured by the nebula,
are only about 100,000 years
old - just babies compared to the 5 billion (5,000,000,000) years of
our Sun.