Astronomy Picture of the Day |
APOD: 2019 June 30 - Virtual Flight over Asteroid Vesta
Explanation:
What would it be like to fly over the asteroid Vesta?
Animators from the
German Aerospace Center took actual images and height data from
NASA's Dawn
mission when it visited asteroid Vesta a few years ago and
generated a virtual movie.
The featured video begins with a sequence above
Divalia Fossa, an unusual pair of troughs running parallel over heavily cratered terrain.
Next, the virtual spaceship explores
Vesta's 60-km
Marcia Crater, showing numerous vivid details.
Last, Dawn images were digitally recast with
exaggerated height to better reveal
Vesta's 5-km high mountain Aricia Tholus.
The second largest object in the
Solar System's asteroid belt,
Vesta is the
brightest asteroid visible from Earth and can be found with binoculars.
Using
Vesta Trek,
you can explore all over Vesta yourself.
APOD: 2018 July 19 - Cerealia Facula
Explanation:
Cerealia Facula,
also known as the
brightest
spot on Ceres,
is shown in this stunning mosaic close-up view.
The
high-resolution image data was recorded by
the Dawn spacecraft, in a looping orbit,
from altitudes as low as 34 kilometers (21 miles) above the
dwarf
planet's surface.
Cerealia Facula is about 15 kilometers wide, found in the center of
90 kilometer diameter
Occator crater.
Like the other bright spots (faculae)
scattered around Ceres,
Cerealia Facula is not ice, but an exposed salty residue with
a reflectivity like dirty snow.
The residue is thought to be mostly sodium carbonate and ammonium chloride
from a slushy brine within or below the dwarf planet's crust.
Driven by advanced ion propulsion on an 11-year mission,
Dawn explored main-belt asteriod Vesta before traveling on to Ceres.
But sometime between this August and October, the interplanetary spacecraft
is expected to finally run out of fuel for its hydrazine thrusters.
The subsequent loss of control of its orientation will result in the
loss of power and the ability to communicate with Earth.
Meanwhile Dawn will continue to explore Ceres in unprecedented detail,
and ultimately retire in its
orbit
around the small world.
APOD: 2015 April 21 - Vesta Trek: A Digital Model of Asteroid Vesta
Explanation:
You can explore asteroid Vesta.
Recently, NASA's robotic spaceship
Dawn visited
Vesta,
the second largest object in our Solar System's main
asteroid belt,
which lies between
Mars and
Jupiter.
During a year-long stopover,
Dawn's cameras photographed
Vesta's entire surface, documenting all of the
minor planet's major mountains and craters.
These images have now been combined into a
digital model that allows
anyone with a full-featured browser to
fly all around Vesta, virtually,
and even zoom in on
interesting
surface
features, by just dragging and clicking.
If desired, the initially flat 2D map can be wrapped into a
nearly spherical object by clicking on the 3D icon at the bottom.
Dawn departed Vesta in 2012 and is now just beginning to photograph and explore the
mysteries of the largest object in the asteroid belt:
dwarf-planet
Ceres.
APOD: 2014 April 10 - Mars, Ceres, Vesta
Explanation:
That bright, ruddy star you've recently
noticed rising just after sunset isn't a star at all.
That's Mars,
the Red Planet.
Mars is now
near its 2014 opposition (April 8) and closest approach
(April 14), looping through the constellation Virgo
opposite the
Sun in planet Earth's sky.
Clearly outshining bluish Spica, alpha star of Virgo, Mars
is centered in this labeled skyview from early April, that includes
two other solar system worlds approaching their opposition.
On the left, small and faint
asteroid Vesta and
dwarf planet Ceres are seen near star Tau Virginis.
But you'll just have to imagine
NASA's Dawn
spacecraft cruising between the small worlds.
Having left Vesta
in September of 2012, Dawn's
ion engine has been
steadily driving it to match orbits with Ceres, scheduled to arrive
there in February 2015.
Of course, you can also look near Mars for the Moon opposite the Sun in
Earth's sky on the night of April 14/15 ... and see a
total
lunar eclipse.
APOD: 2012 November 27 - Bright Jupiter in Taurus
Explanation:
That bright star you've recently
noticed rising just after sunset isn't a star at all.
It's Jupiter,
the solar system's ruling gas giant.
Bright Jupiter is nearing its December 3rd opposition when it will stand
in Taurus,
opposite the Sun in planet Earth's sky.
Clearly
outshining yellowish Aldebaran, alpha star of Taurus, Jupiter
is centered in this skyview from November 14th, also featuring the
Pleiades and Hyades star clusters,
familiar celestial sights as the northern hemisphere winter approaches.
Sliding your cursor over the image will label the scene and identify
two other solar system worlds approaching their opposition in December.
Small and faint, asteroid Vesta and dwarf planet Ceres are about
10 degrees from Jupiter, near the left edge of the frame.
Of course, you can imagine
NASA's Dawn
spacecraft in this field of view.
Having left Vesta
in September, Dawn's
ion engine is now
steadily driving it to match orbits with Ceres, scheduled to arrive
there in February 2015.
APOD: 2012 September 19 - Leaving Vesta
Explanation:
Next stop: Ceres.
Last week the robotic Dawn spacecraft ended its year-long mission to asteroid
Vesta, becoming the first spacecraft ever to visit this far off world located between Mars and Jupiter, in the Solar System's
main asteroid belt.
Many of the best images taken by Dawn at Vesta have been compiled into the
above encompassing view.
Vesta shows evidence of being a leftover from the early years of our Solar System, a
building block for rocky planets like
Earth.
Vesta's ancient surface shows heavy cratering and
long troughs likely created by huge impacts.
The minor planet's low gravity allows for
surface features like
huge cliffs and a large mountain that reaches twice the height of Earth's
Mount Everest, visible at the image bottom.
Vesta, however, spanning about 500 kilometers across, is only the second most massive object in the asteroid belt.
And so, two weeks ago, Dawn fired its gentle
ion rockets
and has begun chasing the most massive:
Ceres.
If everything goes as planned, Dawn will reach Ceres in
2015.
Ceres looks
quite different to the distant telescope --
but what will Dawn find?
APOD: 2012 June 30 - Conjunctions near Dawn
Explanation:
Now shining in
eastern skies
at dawn, bright planets
Venus and Jupiter join the
Pleiades star cluster in this
sea and sky scape, recorded earlier this
week near Buenos Aires, Argentina.
Venus dominates the scene that includes bright star
Aldebaran
just below and to the right.
The planets are
easy to
spot for early morning risers, but this sky also holds two of our
solar system's small worlds,
Vesta and Ceres, not quite bright enough to
be seen with the unaided eye.
The digital camera's time exposure just captures them, though.
Their positions are indicated when you put your cursor over the image.
In orbit around Vesta, NASA's
Dawn
spacecraft arrived there last
July, but is nearing the end of its visit to the main belt asteroid.
In August, it will set off on its planned journey
to Ceres, arriving at the
dwarf planet in 2015.
APOD: 2012 May 14 - Virtual Flight Over Asteroid Vesta
Explanation:
What would it be like to fly over the asteroid Vesta?
Animators from the
German Aerospace Center recently took actual images and height data from
NASA's Dawn
mission currently visiting Vesta to
generate such a virtual movie.
The above video begins with a sequence above
Divalia Fossa, an unusual pair of troughs running parallel over heavily cratered terrain.
Next, the virtual spaceship explores
Vesta's 60-km
Marcia Crater, showing numerous vivid details.
Last, Dawn images were digitally recast with
exaggerated height to better reveal
Vesta's 5-km high mountain Aricia Tholus.
Currently,
Dawn is
rising away
from Vesta after being close enough to obtain the
most detailed
surface images and
gravity measurements of the Solar System's second largest asteroid.
In August,
Dawn is
scheduled
to blast away from Vesta and head toward
Ceres, the Solar System's largest asteroid.
APOD: 2011 December 10 - Vesta Rocks
Explanation:
These
colorful images are of thin slices of meteorites viewed through a
polarizing microscope.
Part of the group classified as HED
(Howardite, Eucrite, Diogenite)
meteorites for their mineral content, they likely
fell
to Earth from 4 Vesta,
the mainbelt asteroid currently being explored by NASA's
Dawn spacecraft.
Why are they thought to be from Vesta?
Because the HED meteorites have visible and infrared spectra
that match the spectrum of
that
small world.
The hypothesis of their origin on Vesta
is also consistent with data from
Dawn's ongoing observations.
Excavated
by impacts, the diogenites shown here
would have originated deep within the crust of Vesta.
Similar rocks
are also found in the lower crust of planet Earth.
A sample scale is indicated by the white bars,
each 2 millimeters long.
APOD: 2011 November 28 - A Landslide on Asteroid Vesta
Explanation:
Asteroid Vesta is home to some of the most impressive cliffs in the Solar System.
Pictured above near the image center is a very
deep cliff running about 20 kilometers from top to bottom.
The image was taken by the
robotic Dawn spacecraft
that began orbiting the
500-kilometer space rock earlier this year.
The topography of the
scarp
and its surroundings indicates that huge landslides may have occurred
down this slope.
The scarp's origin remains unknown, but parts of the cliff face itself must be quite old as several craters have appeared in it since it was created.
Dawn has now finished up its high altitude mapping survey and will spiral down to a lower altitude orbit to better explore the asteroid's
gravitational field.
During 2012,
Dawn is scheduled to blast away from
Vesta and begin a long journey to the only asteroid belt object known to be larger:
Ceres.
APOD: 2011 September 19 - The South Pole of Asteroid Vesta
Explanation:
What created the circular structure around the south pole of asteroid Vesta?
Pictured above, the bottom of the second largest object in the asteroid belt
was recently imaged for the first time by the robotic
Dawn satellite that arrived last month.
A close inspection of the 260-meter resolution image shows not only hills and
craters and
cliffs and
more craters, but ragged circular features that cover most of the lower right of the 500-kilometer sized object.
Early speculation posits that the structure might have been created by a
collision and coalescence with a smaller asteroid.
Alternatively, the features might have originated in an
internal process soon after the asteroid formed.
New clues might come in the next few months as
Dawn spirals down toward the rocky world and obtains images of increasingly high resolution.
APOD: 2011 August 20 - Stereo Vesta
Explanation:
Get out your
red/blue glasses
and float next to 4 Vesta.
A 500 kilometer diameter
world, Vesta
lies in the main
asteroid belt between the orbits of Mars and Jupiter.
This stereo anaglyph
was constructed from two
separate images recorded on July 24 by the
just
arrived Dawn
spacecraft's framing camera with a resolution of about
500 meters per pixel.
The 3D view features
Vesta's newly discovered terrain,
including long equatorial ridges and troughs and
the prominent string of three craters at the upper
right dubbed
Snowman.
Highlighted in 3D, steep sides of many of the craters
show streaks of both bright and dark material.
Of course, the
ion-driven Dawn
spacecraft is not
marooned
off Vesta.
After a year exploring the asteroid from orbit,
Dawn is scheduled to depart, beginning its journey to
Ceres.
APOD: 2011 August 2 - Asteroid Vesta Full Frame
Explanation:
Why is the northern half of asteroid Vesta more heavily cratered than the south?
No one is yet sure.
This unexpected mystery has come to light only in the past few weeks since the robotic
Dawn mission became the first
spacecraft to orbit the second largest object in the
asteroid belt
between Mars and Jupiter.
The northern half of
Vesta, seen on the upper left of the
above image, appears to show some of the densest cratering in the Solar System, while the southern half is unexpectedly smooth.
Also unknown is the origin of grooves that circle the asteroid nears its equator, particularly visible on
this Vesta rotation movie, and the nature of
dark streaks that delineate some of Vesta's craters, for example the crater just above the
the image center.
As Dawn spirals in toward
Vesta over the coming months, some answers may emerge, as well as higher resolution and color images.
Studying 500-km diameter
Vesta is yielding clues about its history and the early years of our Solar System.
APOD: 2011 July 19 - Vesta Vista
Explanation:
What does the surface of asteroid
Vesta look like?
The brightest asteroid in the
Solar System
and the object which takes up about 10 percent of the entire mass of the
main asteroid belt
had never been seen up close before.
Over the past few weeks, however, the robotic Dawn spacecraft became the first
spacecraft ever to
approach Vesta.
A few days ago, just after attaining orbit, Dawn took the
above image.
Early images show Vesta to be an old and battered world, covered with craters, bulges, grooves, and
cliffs.
Studying
Vesta may give clues to the
formative years of our early Solar System, as the unusual world may be one of the largest remaining
protoplanets.
After a year of
studying Vesta, Dawn is scheduled to leave orbit and, in 2015, approach the only
asteroid-belt object that is larger:
Ceres.
APOD: 2011 June 19 - The Regolith of Asteroid Eros
Explanation:
From fifty kilometers above asteroid
Eros,
the surface inside one of its largest craters
appears covered with an unusual substance:
regolith.
The thickness and composition of
the surface
dust that is
regolith remains a topic of much research.
Much of the regolith on
433 Eros was probably created by numerous small
impacts during its long history.
In this representative-color view taken by the
robot spacecraft NEAR-SHOEMAKER that
orbited Eros in 2000 and 2001, brown areas indicate
regolith that has been chemically altered by exposure to the
solar wind during
micrometeorite impacts.
White areas are thought to have undergone relatively less exposure.
The boulders visible
inside the crater appear brown,
indicating either that they are old enough to have a
surface itself tanned by the
solar wind, or that they have somehow become
covered with some dark surface
dust.
This July, NASA's
Dawn spacecraft
will orbit giant main belt asteroid Vesta.
APOD: 2010 February 18 - Vesta Near Opposition
Explanation:
Main belt
asteroid 4 Vesta is at its brightest now.
The small world
is near opposition (opposite the Sun in the sky)
and closest to Earth.
But even at its brightest,
Vesta
is just too faint to spot with the naked-eye.
Still, over the next few days it will be relatively easy to
find in the constellation Leo, sharing a typical binocular field of
view with bright star
Gamma Leonis
(aka Algieba).
In fact on February 16
Vesta
passed between Gamma Leonis and close neighbor on the sky 40 Leonis.
Gamma Leonis is the brightest star in these two panels, while
the second brightest star, 40 Leonis, is directy to its right.
As marked, Vesta is the third brightest "star" in the field.
Vesta shifts position between the two panels from well below 40 Leonis
on Feb. 14 to near the top of the frame from Feb. 16, shooting the gap
between the close Gamma/40 Leonis pair.
Of course, premier close-up views of the asteroid will be possible
after the ion-powered Dawn
spacecraft arrives at Vesta in August of 2011.
APOD: 2007 September 29 - Dawn Launch Mosaic
Explanation:
Shortly
after sunrise on Thursday at
Cape Canaveral
Air Force Station, the
Dawn
spacecraft began its journey to the asteroid belt,
arcing eastward into a blue and cloudy sky.
Dawn's voyage began on a conventional,
chemically
fueled Delta II
rocket, but will continue with an
innovative
ion propulsion system.
The spacecraft's extremely
efficient
ion engines will use electricity
derived from solar power to ionize xenon atoms and generate
a gentle but continuous thrust.
After a four year interplanetary cruise, Dawn will orbit
two small worlds, first Vesta and then Ceres.
Vesta is one of the largest main belt asteroids, while nomenclature
introduced by the International Astronomical Union in 2006 classifies
nearly spherical Ceres as a dwarf planet.
APOD: 2007 June 22 - Small Worlds Ceres and Vesta
Explanation:
Ceres and
Vesta are, respectively, only
around 950 kilometers and 530 kilometers in diameter - about
the size of Texas and Arizona.
But they are two of the largest of over 100,000
minor bodies
orbiting in the main asteroid belt between Mars and Jupiter.
These remarkably detailed
Hubble Space Telescope images
show brightness and color variations
across the surface of the two small worlds.
The variations could represent large scale
surface features or areas of different compositon.
The Hubble image data will help astronomers plan for a
visit by the asteroid-hopping
Dawn spacecraft,
scheduled for launch on July 7 and intended to orbit first
Vesta and then
Ceres after a four year interplanetary cruise.
Though
Shakespeare might not have been impressed,
nomenclature introduced by the International Astronomical
Union in 2006 classifies nearly spherical Ceres as a
dwarf planet.
APOD: 2007 May 25 - Jupiter, Vesta, and the Milky Way
Explanation:
In this gorgeous skyscape, gas giant Jupiter
along with the stars and cosmic dust clouds
of the Milky Way
hang over the southern horizon in the
early morning hours as seen from Stagecoach, Colorado, USA.
Recorded on Thursday, Jupiter is the brightest object near picture
center.
Along with the stunning Milky Way, Jupiter is hard to miss,
but a
careful
inspection of the view also reveals
main belt
asteroid Vesta.
Of all the asteroids
Vesta is the brightest and
is now just bright enough to be visible to the naked eye
from locations with very dark, clear skies.
Vesta (as well as Jupiter) appears relatively
bright now because it is near opposition, literally opposite the Sun
in planet Earth's sky and closest to Earth in its orbit.
For Vesta, this opposition
offers the best viewing in many years.
The year 2007 also
coincides
with the 200th anniversary of
the asteroid's
discovery.
Starting late next month, NASA plans to launch the
Dawn mission intended
to explore Vesta (and Ceres) and the main asteroid belt.
APOD: 2006 August 21 - Ceres: Asteroid or Planet
Explanation:
Is
Ceres an
asteroid or a planet?
Although a trivial designation to some, the recent suggestion by the
Planet Definition Committee of the
International Astronomical Union would have Ceres reclassified from asteroid to planet.
A change in taxonomy might lead to more notoriety for the frequently overlooked world.
Ceres,
at about 1000 kilometers across, is the largest object in the
main asteroid belt
between Mars and Jupiter.
Under the
newly proposed criteria, Ceres would qualify as a planet because it is nearly
spherical and sufficiently distant from other planets.
Pictured above is the best picture yet of Ceres, taken by the
Hubble Space Telescope
as part of a series of exposures ending in 2004 January.
Currently, NASA's
Dawn mission is scheduled to launch in 2007 June to explore
Ceres and Vesta,
regardless of their future designations.
APOD: 2006 August 20 - A Map of Asteroid Vesta
Explanation:
Vesta is a huge rock 500 kilometers across that orbits out past
Mars.
In 1997, the
above map of
Vesta created using the
Hubble Space Telescope
was released showing a rugged surface highlighted by a
single crater spanning nearly the entire length of the
asteroid.
The large crater dominates the lower part of the
above false-color conglomerate image: blue indicates low terrain,
while red indicates raised terrain.
Evidence indicates that
Vesta underwent a tremendous splintering collision about a billion years ago.
In October 1960, a small chunk of this rock believed to have originated on Vesta fell to
Earth and was recovered in
Australia.
Vesta is considered by some to be a candidate for
reclassification into a planet.
APOD: 2002 January 18 - Saturn and Vesta in Taurus
Explanation:
Last November,
while skygazing toward the constellation
Taurus,
astrophotographer Joe Orman arranged this time exposure to
include the lovely Hyades and Pleiades star clusters in the
field of his telephoto lens.
A distance of 400 light-years
for the close-knit
Pleiades
and 150 light-years for the
V-shaped
Hyades
puts these clusters in the general galactic
neighborhood of the Sun.
Punctuating the Hyades' appearance, bright yellow
Aldebaran,
60 light-years away, is not actually a member of the cluster, but it is
Taurus' brightest star.
Above Aldebaran a yellower, even brighter
Saturn
is is seen about 1.2
light-hours
from our fair planet.
Last and least
massive,
one of the faint specks below Aldebaran is
main-belt asteroid Vesta, a mere 13
light-minutes away.
Still cruising through Taurus,
Vesta
is steadily approaching a
close alignment or conjunction with Saturn on March 19.
Need a program to follow the players?
Click on the image
for a labeled version.
APOD: August 5, 1999 - Asteroid 9969 Braille
Explanation:
NASA probe
Deep Space 1 zoomed past asteroid
9969 Braille last week as it continued to test its new
ion drive in the inner Solar System.
The flyby was the closest approach a spacecraft
has ever made to an
asteroid.
Looking back afterwards, DS1 took the
above picture.
Formerly known as 1992 KD, the 9969th asteroid
discovered was renamed in honor of Louis Braille, a pioneer in written communication for the blind.
9969 Braille is thought by some to have collided with
asteroid Vesta in the distant past and broken up,
providing debris for many of the meteorites that fall to Earth.
Asteroid 9969 Braille rotates only once in 9 days, and has an orbit greatly tilted relative to the
ecliptic plane of the planets.
APOD: September 8, 1997 - A Map of Asteroid Vesta
Explanation:
Vesta is a huge rock 500 kilometers across that orbits out past
Mars. Last week, the
above map of
Vesta created using the
Hubble Space Telescope
was released showing a rugged surface highlighted by a
single crater spanning nearly the entire length of the asteroid.
The large crater dominates the lower part of the false-color
conglomerate image: blue indicates low terrain,
while red indicates raised terrain. Evidence indicates that
Vesta underwent a tremendous splintering collision about a billion years ago.
In October 1960, a small chunk of this rock believed to have originated on Vesta fell to
Earth and was recovered in
Australia.