Astronomy Picture of the Day Search Results for "Meteor"

APOD: 2024 December 12 - Phaethon s Brood
Explanation: Based on its well-measured orbit, 3200 Phaethon (sounds like FAY-eh-thon) is recognized as the source of the meteoroid stream responsible for the annual Geminid meteor shower. Even though most meteor shower parents are comets, 3200 Phaethon is a known and closely tracked near-Earth asteroid with a 1.4 year orbital period. Rocky and sun-baked, its perihelion or closest approach to the Sun is well within the orbit of innermost planet Mercury. In this telescopic field of view, the asteroid's rapid motion against faint background stars of the heroic constellation Perseus left a short trail during the two minute total exposure time. The (faint) parallel streaks of its meteoric children flashed much more quickly across the scene. The family portrait was recorded near the Geminid meteor shower's very active peak on 2017 December 13. That was just three days before 3200 Phaethon's historic close approach to planet Earth. This year, the night of December 13 should again see the peak of the Geminid meteor shower, but faint meteors will be washed out by the bright light of the nearly full moon.

APOD: 2024 December 10 – The Great Meteor Storm of 1833
Explanation: It was a night of 100,000 meteors. The Great Meteor Storm of 1833 was perhaps the most impressive meteor event in recent history. Best visible over eastern North America during the pre-dawn hours of November 13, many people -- including a young Abraham Lincoln -- were woken up to see the sky erupt in streaks and flashes. Hundreds of thousands of meteors blazed across the sky, seemingly pouring out of the constellation of the Lion (Leo). The featured image is a digitization of a wood engraving which itself was based on a painting from a first-person account. We know today that the Great Meteor Storm of 1833 was caused by the Earth moving through a dense part of the dust trail expelled from Comet Tempel-Tuttle. The Earth moves through this dust stream every November during the Leonid meteor shower. Later this week you might get a slight taste of the intensity of that 1833 meteor storm by witnessing the annual Geminid meteor shower.

APOD: 2024 November 27 – The Meteor and the Comet
Explanation: How different are these two streaks? The streak on the upper right is Comet Tsuchinshan-Atlas showing an impressive dust tail. The comet is a large and dirty iceberg that entered the inner Solar System and is shedding gas and dust as it is warmed by the Sun's light. The streak on the lower left is a meteor showing an impressive evaporation trail. The meteor is a small and cold rock that entered the Earth's atmosphere and is shedding gas and dust as it is warmed by molecular collisions. The meteor was likely once part of a comet or asteroid -- perhaps later composing part of its tail. The meteor was gone in a flash and was only caught by coincidence during a series of exposures documenting the comet's long tail. The featured image was captured just over a month ago from Sichuan Province in China.

APOD: 2024 August 26 – Perseid Meteors Over Inner Mongolia
Explanation: Did you see it? One of the more common questions during a meteor shower occurs because the time it takes for a meteor to flash is similar to the time it takes for a head to turn. Possibly, though, the glory of seeing bright meteors shoot across the sky -- while knowing that they were once small pebbles on another world -- might make it all worthwhile, even if your observing partner(s) can't always share in your experience. The featured video is composed of short clips taken in Inner Mongolia, China during the 2023 Perseid Meteor Shower. Several bright meteors were captured while live-reaction audio was being recorded -- just as the meteors flashed. This year's 2024 Perseids also produced many beautiful meteors. Another good meteor shower to watch for is the Geminids which peak yearly in mid-December, this year with relatively little competing glow from a nearly new Moon.

APOD: 2024 August 16 - Meteor Borealis
Explanation: A single exposure made with a camera pointed almost due north on August 12 recorded this bright Perseid meteor in the night sky west of Halifax, Nova Scotia, Canada. The meteor's incandescent trace is fleeting. It appears to cross the stars of the Big Dipper, famous northern asterism and celestial kitchen utensil, while shimmering curtains of aurora borealis, also known as the northern lights, dance in the night. Doubling the wow factor for night skywatchers near the peak of this year's Perseid meteor shower auroral activity on planet Earth was enhanced by geomagnetic storms. The intense space weather was triggered by flares from an active Sun.

APOD: 2024 August 12 – Perseid Meteors over Stonehenge
Explanation: What's happening in the sky above Stonehenge? A meteor shower: specifically, the Perseid meteor shower. A few nights ago, after the sky darkened, many images of meteors from this year's Perseids were captured separately and merged into a single frame. Although the meteors all traveled on straight paths, these paths appear slightly curved by the wide-angle lens of the capturing camera. The meteor streaks can all be traced back to a single point on the sky called the radiant, here just off the top of the frame in the constellation of Perseus. The same camera took a deep image of the background sky that brought up the central band of our Milky Way galaxy running nearly vertical through the image center. The featured image was taken from Wiltshire, England, being careful to include, at the bottom, the famous astronomical monument of Stonehenge. Although the Perseids peaked last night, some Perseid meteors should still be visible for a few more nights.

APOD: 2024 August 11 – Animation: Perseid Meteor Shower
Explanation: Where do Perseid meteors come from? Mostly small bits of stony grit, Perseid meteoroids were once expelled from Comet Swift-Tuttle and continue to follow this comet's orbit as they slowly disperse. The featured animation depicts the entire meteoroid stream as it orbits our Sun. When the Earth nears this stream, as it does every year, the Perseid Meteor Shower occurs. Highlighted as bright in the animation, comet debris this size is usually so dim it is practically undetectable. Only a small fraction of this debris will enter the Earth's atmosphere, heat up and disintegrate brightly. Tonight and the next few nights promise some of the better skies to view the Perseid shower as well as other active showers because the first quarter moon will be absent from the sky from midnight onward.

APOD: 2024 August 9 - A Perseid Below
Explanation: Denizens of planet Earth typically watch meteor showers by looking up. But this remarkable view, captured on August 13, 2011 by astronaut Ron Garan, caught a Perseid meteor by looking down. From Garan's perspective on board the International Space Station orbiting at an altitude of about 380 kilometers, the Perseid meteors streak below, swept up dust from comet Swift-Tuttle. The vaporizing comet dust grains are traveling at about 60 kilometers per second through the denser atmosphere around 100 kilometers above Earth's surface. In this case, the foreshortened meteor flash is near frame center, below the curving limb of the Earth and a layer of greenish airglow, just below bright star Arcturus. Want to look up at a meteor shower? You're in luck, as the 2024 Perseid meteor shower is active now and predicted to peak near August 12. With interfering bright moonlight absent, this year you'll likely see many Perseid meteors under clear, dark skies after midnight.

APOD: 2024 July 14 – Meteor Misses Galaxy
Explanation: The galaxy was never in danger. For one thing, the Triangulum galaxy (M33), pictured, is much bigger than the tiny grain of rock at the head of the meteor. For another, the galaxy is much farther away -- in this instance 3 million light years as opposed to only about 0.0003 light seconds. Even so, the meteor's path took it angularly below the galaxy. Also the wind high in Earth's atmosphere blew the meteor's glowing evaporative molecule train away from the galaxy, in angular projection. Still, the astrophotographer was quite lucky to capture both a meteor and a galaxy in a single exposure -- which was subsequently added to two other images of M33 to bring up the spiral galaxy's colors. At the end, the meteor was gone in a second, but the galaxy will last billions of years.

APOD: 2024 February 17 - Meteor over the Bay of Naples
Explanation: A cosmic dust grain plowing through the upper atmosphere much faster than a falling leaf created this brilliant meteor streak. In a serendipitous moment, the sublime night sky view was captured from the resort island of Capri, in the Bay of Naples, on the evening of February 8. Looking across the bay, the camera faces northeast toward the lights of Naples and surrounding cities. Pointing toward the horizon, the meteor streak by chance ends above the silhouette of Mount Vesuvius. One of planet Earth's most famous volcanos, an eruption of Mount Vesuvius destroyed the city of Pompeii in 79 AD.

APOD: 2023 December 28 - Jupiter and the Geminid
Explanation: For a brief moment, this brilliant fireball meteor outshone Jupiter in planet Earth's night. The serendipitous image was captured while hunting meteors under cold Canadian skies with a camera in timelapse mode on December 14, near the peak of the Geminid meteor shower. The Geminid meteor shower, asteroid 3200 Phaethon's annual gift, always arrives in December. Dust shed along the orbit of the mysterious asteroid causes the meteor streaks, as the vaporizing grains plow through our fair planet's upper atmosphere at 22 kilometers per second. Of course Geminid shower meteors appear to radiate from a point in the constellation of the Twins. That's below and left of this frame. With bright Jupiter on the right, also in the December night skyview are the Pleiades and Hyades star clusters.

APOD: 2023 December 17 – Geminids over China's Nianhu Lake
Explanation: Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Gemini. That is why the major meteor shower in December is known as the Geminids -- because shower meteors all appear to come from a radiant toward Gemini. Three dimensionally, however, sand-sized debris expelled from the unusual asteroid 3200 Phaethon follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation of Gemini. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Gemini. Featured here is a composite of many images taken a few days ago through dark skies from Nianhu Lake in China. Over 100 bright meteor streaks from the Geminids meteor shower are visible.

APOD: 2023 August 23 – The Meteor and the Galaxy
Explanation: It came from outer space. It -- in this case a sand-sized bit of a comet nucleus -- was likely ejected many years ago from Sun-orbiting Comet Swift-Tuttle, but then continued to orbit the Sun alone. When the Earth crossed through this orbit, the piece of comet debris impacted the atmosphere of our fair planet and was seen as a meteor. This meteor deteriorated, causing gases to be emitted that glowed in colors emitted by its component elements. The featured image was taken last week from Castilla La Mancha, Spain, during the peak night of the Perseids meteor shower. The picturesque meteor streak happened to appear in the only one of 50 frames that also included the Andromeda galaxy. Stars dot the frame, each much further away than the meteor. Compared to the stars, the Andromeda galaxy (M31) is, again, much further away.

APOD: 2023 August 9 – Meteor Shower: Perseids from Perseus
Explanation: This is a good week to see meteors. Comet dust will rain down on planet Earth, streaking through dark skies during peak nights of the annual Perseid Meteor Shower. The featured composite image was taken during the 2018 Perseids from the Poloniny Dark Sky Park in Slovakia. The dome of the observatory in the foreground is on the grounds of Kolonica Observatory. Although the comet dust particles travel parallel to each other, the resulting shower meteors clearly seem to radiate from a single point on the sky in the eponymous constellation Perseus. The radiant effect is due to perspective, as the parallel tracks appear to converge at a distance, like train tracks. The Perseid Meteor Shower is expected to reach its highest peak on Saturday after midnight. Since a crescent Moon will rise only very late that night, cloudless skies will be darker than usual, making a high number of faint meteors potentially visible this year.

APOD: 2023 July 24 – Chemicals Glow as a Meteor Disintegrates
Explanation: Meteors can be colorful. While the human eye usually cannot discern many colors, cameras often can. Pictured here is a fireball, a disintegrating meteor that was not only one of the brightest the photographer has ever seen, but colorful. The meteor was captured by chance in mid-July with a camera set up on Hochkar Mountain in Austria to photograph the central band of our Milky Way galaxy. The radiant grit, likely cast off by a comet or asteroid long ago, had the misfortune to enter Earth's atmosphere. Colors in meteors usually originate from ionized chemical elements released as the meteor disintegrates, with blue-green typically originating from magnesium, calcium radiating violet, and nickel glowing green. Red, however, typically originates from energized nitrogen and oxygen in the Earth's atmosphere. This bright meteoric fireball was gone in a flash -- less than a second -- but it left a wind-blown ionization trail that remained visible for almost a minute.

APOD: 2023 July 16 – Meteor and Milky Way over the Alps
Explanation: Now this was a view with a thrill. From Mount Tschirgant in the Alps, you can see not only nearby towns and distant Tyrolean peaks, but also, weather permitting, stars, nebulas, and the band of the Milky Way Galaxy. What made the arduous climb worthwhile this night, though, was another peak -- the peak of the 2018 Perseids Meteor Shower. As hoped, dispersing clouds allowed a picturesque sky-gazing session that included many faint meteors, all while a carefully positioned camera took a series of exposures. Suddenly, a thrilling meteor -- bright and colorful -- slashed down right next to the nearly vertical band of the Milky Way. As luck would have it, the camera caught it too. Therefore, a new image in the series was quickly taken with one of the sky-gazers posing on the nearby peak. Later, all of the images were digitally combined.

APOD: 2023 February 17 - 2023 CX1 Meteor Flash
Explanation: While scanning the skies for near-Earth objects Hungarian astronomer Krisztián Sárneczky first imaged the meter-sized space rock now cataloged as 2023 CX1 on 12 February 2023 at 20:18:07 UTC. That was about 7 hours before it impacted planet Earth's atmosphere. Its predicted trajectory created a rare opportunity for meteor observers and a last minute plan resulted in this spectacular image of the fireball, captured from the Netherlands as 2023 CX1 vaporized and broke up over northern France. Remarkably it was Sárneczky's second discovery of an impacting asteroid, while 2023 CX1 is only the seventh asteroid to be detected before being successfully predicted to impact Earth. It has recently become the third such object from which meteorites have been recovered. This fireball was witnessed almost 10 years to the day following the infamous Chelyabinsk Meteor flash.

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 August 23 - Meteor and Milky Way over the Mediterranean
Explanation: Careful planning made this a nightscape to remember. First, the night itself was chosen to occur during the beginning of this year's Perseid Meteor Shower. Next, the time of night was chosen to be before the bright Moon would rise and dominate the night sky's brightness. The picturesque foreground was selected to be a rocky beach of the Mediterranean Sea in Le Dramont, France, with, at the time, île d’Or island situated near the ominously descending central band of our Milky Way Galaxy. Once everything was set and with the weather cooperating, all of the frames for this seemingly surreal nightscape were acquired within 15 minutes. What you can't see is that, on this night, the astrophotographer brought along his father who, although unskilled in modern sky-capture techniques, once made it a point to teach his child about the sky.

APOD: 2022 August 18 - Full Moon Perseids
Explanation: The annual Perseid meteor shower was near its peak on August 13. As planet Earth crossed through streams of debris left by periodic Comet Swift-Tuttle meteors rained in northern summer night skies. But even that night's nearly Full Moon shining near the top of this composited view couldn't hide all of the popular shower's meteor streaks. The image captures some of the brightest perseid meteors in many short exposures recorded over more than two hours before the dawn. It places the shower's radiant in the heroic constellation of Perseus just behind a well-lit medieval tower in the village of Sant Llorenc de la Muga, Girona, Spain. Observed in medieval times, the Perseid meteor shower is also known in Catholic tradition as the Tears of St. Lawrence, and festivities are celebrated close to the annual peak of the meteor shower. Joining the Full Moon opposite the Sun, bright planet Saturn also shines in the frame at the upper right.

APOD: 2022 August 16 - A Meteor Wind over Tunisia
Explanation: Does the Earth ever pass through a wind of meteors? Yes, and they are frequently visible as meteor showers. Almost all meteors are sand-sized debris that escaped from a Sun-orbiting comet or asteroid, debris that continues in an elongated orbit around the Sun. Circling the same Sun, our Earth can move through an orbiting debris stream, where it can appear, over time, as a meteor wind. The meteors that light up in Earth's atmosphere, however, are usually destroyed. Their streaks, though, can all be traced back to a single point on the sky called the radiant. The featured image composite was taken over two days in late July near the ancient Berber village Zriba El Alia in Tunisia, during the peak of the Southern Delta Aquariids meteor shower. The radiant is to the right of the image. A few days ago our Earth experienced the peak of a more famous meteor wind -- the Perseids.

APOD: 2022 August 7 - Meteor before Galaxy
Explanation: What's that green streak in front of the Andromeda galaxy? A meteor. While photographing the Andromeda galaxy in 2016, near the peak of the Perseid Meteor Shower, a small pebble from deep space crossed right in front of our Milky Way Galaxy's far-distant companion. The small meteor took only a fraction of a second to pass through this 10-degree field. The meteor flared several times while braking violently upon entering Earth's atmosphere. The green color was created, at least in part, by the meteor's gas glowing as it vaporized. Although the exposure was timed to catch a Perseid meteor, the orientation of the imaged streak seems a better match to a meteor from the Southern Delta Aquariids, a meteor shower that peaked a few weeks earlier. Not coincidentally, the Perseid Meteor Shower peaks later this week, although this year the meteors will have to outshine a sky brightened by a nearly full moon.

APOD: 2022 June 4 - Tau Herculids from Space
Explanation: On May 31 tens of parallel meteor streaks were recorded in this 8 degree wide field of view of planet Earth's limb from space. The image is one of a series of 5 minute long observations by the orbiting Yangwang-1 space telescope. It was captured at 03:43 UT, near the peak of the Tau Herculid meteor shower. As predicted, the meteor shower was an active one this year, caused as Earth swept through a relatively dense stream of debris from disintegrating Comet 73P/Schwassmann-Wachmann 3, but was lacking bright meteors. Nearly all of the Tau Herculid meteors in the Yangwang-1 image are too faint to be detected by groundbased instruments. But on that date patient earthbound skywatchers under clear skies still enjoyed a memorable showing of the Tau Herculids.

APOD: 2022 June 1 - Tau Herculid Meteors over Kitt Peak Telescopes
Explanation: It wasn't the storm of the century -- but it was a night to remember. Last night was the peak of the Tau Herculid meteor shower, a usually modest dribble of occasional meteors originating from the disintegrating Comet 73P/Schwassmann-Wachmann 3. This year, calculations showed that the Earth might be passing through a particularly dense stream of comet debris -- at best creating a storm of bright meteors streaking out from the constellation of Hercules. What actually happened fell short of a meteor storm, but could be called a decent meteor shower. Featured here is a composite image taken at Kitt Peak National Observatory in Arizona, USA accumulated over 2.5 hours very late on May 30. Over that time, 19 Tau Herculids meteors were captured, along with 4 unrelated meteors. (Can you find them?) In the near foreground is the Bok 2.3-meter Telescope with the 4.0-meter Mayall Telescope just behind it. Next year, the annual Tau Herculids are expected to return to its normal low rate, with the next active night forecast for 2049.

APOD: 2021 December 20 - The Comet and the Fireball
Explanation: This picture was supposed to feature a comet. Specifically, a series of images of the brightest comet of 2021 were being captured: Comet Leonard. But the universe had other plans. Within a fraction of a second, a meteor so bright it could be called a fireball streaked through just below the comet. And the meteor's flash was even more green than the comet's coma. The cause of the meteor's green was likely magnesium evaporating from the meteor's pebble-sized core, while the cause of the comet's green was likely diatomic carbon recently ejected from the comet's city-sized nucleus. The images were taken 10 days ago over the Sacramento River and Mt. Lassen in California, USA. The fireball was on the leading edge of this year's Geminid Meteor Shower -- which peaked a few days later. Comet Leonard is now fading after reaching naked-eye visibility last week -- but now is moving into southern skies.

APOD: 2021 November 16 - Geminids from Gemini
Explanation: Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Gemini. That is why the major meteor shower in December is known as the Geminids -- because shower meteors all appear to come from a radiant toward Gemini. Three dimensionally, however, sand-sized debris expelled from the unusual asteroid 3200 Phaethon follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation of Gemini. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Gemini. Featured here, a composite of many images taken during the 2020 Geminids meteor shower shows over 200 bright meteors that streaked through the sky during the night December 14. The best meteor shower in November, the Leonids, peaks tonight and tomorrow. Unfortunately, this year, dim meteors during the early-morning peak will be hard to see against a sky lit by a bright gibbous moon. Still, a few bright Leonid meteors should be visible each hour.

APOD: 2021 October 12 - Fireball over Lake Louise
Explanation: What makes a meteor a fireball? First of all, everyone agrees that a fireball is an exceptionally bright meteor. Past that, the International Astronomical Union defines a fireball as a meteor brighter than apparent magnitude -4, which corresponds (roughly) to being brighter than any planet -- as well as bright enough to cast a human-noticeable shadow. Pictured, an astrophotographer taking a long-duration sky image captured by accident the brightest meteor he had ever seen. Clearly a fireball, the disintegrating space-rock created a trail so bright it turned night into day for about two seconds earlier this month. The fireball has been artificially dimmed in the featured image to bring up foreground Lake Louise in Alberta, Canada. Although fireballs are rare, many people have been lucky enough to see them. If you see a fireball, you can report it. If more than one person recorded an image, the fireball might be traceable back to the Solar System body from which it was ejected.

APOD: 2021 August 19 - Bright Meteor, Starry Sky
Explanation: Plowing through Earth's atmosphere at 60 kilometers per second, this bright perseid meteor streaks along a starry Milky Way. Captured in dark Portugal skies on August 12, it moves right to left through the frame. Its colorful trail starts near Deneb (alpha Cygni) and ends near Altair (alpha Aquilae), stars of the northern summer triangle. In fact this perseid meteor very briefly outshines both, two of the brightest stars in planet Earth's night. The trail's initial greenish glow is typical of the bright perseid shower meteors. The grains of cosmic sand, swept up dust from periodic comet Swift-Tuttle, are moving fast enough to excite the characteristic green emission of atomic oxygen at altitudes of 100 kilometers or so before vaporizing in an incandescent flash.

APOD: 2021 August 16 - Perseid Meteor, Red Sprites, and Nova RS Oph
Explanation: This was an unusual sky. It wasn't unusual because of the central band the Milky Way Galaxy, visible along the image left. Most dark skies show part of the Milky Way. It wasn't unusual because of the bright meteor visible on the upper right. Many images taken during last week's Perseid Meteor Shower show meteors, although this Perseid was particularly bright. This sky wasn't unusual because of the red sprites, visible on the lower right. Although this type of lightning has only been noted in the past few decades, images of sprites are becoming more common. This sky wasn't unusual because of the nova, visible just above the image center. Novas bright enough to be seen with the unaided eye occur every few years, with pictured Nova RS Ophiuchus discovered about a week ago. What was most unusual, though, was to capture all these things together, in a single night, on a single sky. The unusual sky occurred above Zacatecas, Mexico.

APOD: 2021 August 14 - Island Universe, Cosmic Sand
Explanation: Stars in our own Milky Way Galaxy are scattered through this eye-catching field of view. From the early hours after midnight on August 13, the 30 second exposure of the night sky over Busko-Zdroj, Poland records the colorful and bright trail of a Perseid meteor. Seen near the peak of the annual Perseid meteor shower it flashes from lower left to upper right. The hurtling grain of cosmic sand, a piece of dust from periodic comet Swift-Tuttle, vaporized as it passed through planet Earth's atmosphere at almost 60 kilometers per second. Just above and right of center, well beyond the stars of the Milky Way, lies the island universe known as M31 or the Andromeda Galaxy. The Andromeda Galaxy is the most distant object easily visible to the naked-eye, about 2.5 million light-years away. The visible meteor trail begins only about 100 kilometers above Earth's surface, though. It points back to the meteor shower radiant in the constellation Perseus off the lower left edge of the frame. Follow this bright perseid meteor trail below and left to the stars of NGC 869and NGC 884, the double star cluster in Perseus.

APOD: 2021 August 9 - Perseus and the Lost Meteors
Explanation: What's the best way to watch a meteor shower? This question might come up later this week when the annual Perseid Meteor Shower peaks. One thing that is helpful is a dark sky, as demonstrated in the featured composite image of last year's Perseids. Many more faint meteors are visible on the left image, taken through a very dark sky in Slovakia, than on the right image, taken through a moderately dark sky in the Czech Republic. The band of the Milky Way Galaxy bridges the two coordinated images, while the meteor shower radiant in the constellation of Perseus is clearly visible on the left. In sum, many faint meteors are lost through a bright sky. Light pollution is shrinking areas across our Earth with dark skies, although inexpensive ways to combat this might be implemented.

APOD: 2021 August 8 - A Perseid Below
Explanation: Earthlings typically watch meteor showers by looking up. But this remarkable view, captured on August 13, 2011 by astronaut Ron Garan, caught a Perseid meteor by looking down. From Garan's perspective onboard the International Space Station orbiting at an altitude of about 380 kilometers, the Perseid meteors streak below, swept up dust left from comet Swift-Tuttle heated to incandescence. The glowing comet dust grains are traveling at about 60 kilometers per second through the denser atmosphere around 100 kilometers above Earth's surface. In this case, the foreshortened meteor flash is right of frame center, below the curving limb of the Earth and a layer of greenish airglow, just below bright star Arcturus. Want to look up at a meteor shower? You're in luck, as the 2021 Perseids meteor shower peaks this week. This year, even relatively faint meteors should be visible through clear skies from a dark location as the bright Moon will mostly absent.

APOD: 2021 August 3 - A Perseid Meteor and the Milky Way
Explanation: It was bright and green and flashed as it moved quickly along the Milky Way. It left a trail that took 30 minutes to dissipate. Given the day, August 12, and the direction, away from Perseus, it was likely a small bit from the nucleus of Comet Swift-Tuttle plowing through the Earth's atmosphere -- and therefore part of the annual Perseids meteor shower. The astrophotographer captured the fireball as it shot across the sky in 2018 above a valley in Yichang, Hubei, China. The meteor's streak, also caught on video, ended near the direction of Mars on the lower left. Next week, the 2021 Perseids meteor shower will peak again. This year the Moon will set shortly after the Sun, leaving a night sky ideal for seeing lots of Perseids from dark and clear locations across planet Earth.

APOD: 2021 May 12 - A Meteor and the Gegenschein
Explanation: Is the night sky darkest in the direction opposite the Sun? No. In fact, a rarely discernable faint glow known as the gegenschein (German for "counter glow") can be seen 180 degrees around from the Sun in an extremely dark sky. The gegenschein is sunlight back-scattered off small interplanetary dust particles. These dust particles are millimeter sized splinters from asteroids and orbit in the ecliptic plane of the planets. Pictured here from last March is one of the more spectacular pictures of the gegenschein yet taken. The deep exposure of an extremely dark sky over Teide Observatory in Spain's Canary Islands shows the gegenschein as part of extended zodiacal light. Notable background objects include a bright meteor (on the left), the Big Dipper (top right), and Polaris (far right). The meteor nearly points toward Mount Teide, Spain's highest mountain, while the Pyramid solar laboratory is visible on the right. During the day, a phenomenon like the gegenschein called the glory can be seen in reflecting air or clouds opposite the Sun from an airplane.

APOD: 2021 March 15 - Meteor Fireballs in Light and Sound
Explanation: Yes, but have you ever heard a meteor? Usually, meteors are too far away to make any audible sound. However, a meteor will briefly create an ionization trail that can reflect a distant radio signal. If the geometry is right, you may momentarily hear -- through your radio -- a distant radio station even over static. In the featured video, the sounds of distant radio transmitters were caught reflecting from large meteor trails by a sensitive radio receiver -- at the same time the bright streaks were captured by an all-sky video camera. In the video, the bright paths taken by four fireballs across the sky near Lamy, New Mexico, USA, are shown first. Next, after each static frame, a real-time video captures each meteor streaking across the sky, now paired with the sound recorded from its radio reflection. Projecting a meteor trail down to the Earth may lead to finding its impact site (if any), while projecting its trail back into the sky may lead to identifying its parent comet or asteroid.

APOD: 2021 February 2 - A Colorful Quadrantid Meteor
Explanation: Meteors can be colorful. While the human eye usually cannot discern many colors, cameras often can. Pictured is a Quadrantids meteor captured by camera over Missouri, USA, early this month that was not only impressively bright, but colorful. The radiant grit, likely cast off by asteroid 2003 EH1, blazed a path across Earth's atmosphere. Colors in meteors usually originate from ionized elements released as the meteor disintegrates, with blue-green typically originating from magnesium, calcium radiating violet, and nickel glowing green. Red, however, typically originates from energized nitrogen and oxygen in the Earth's atmosphere. This bright meteoric fireball was gone in a flash -- less than a second -- but it left a wind-blown ionization trail that remained visible for several minutes.

APOD: 2020 December 17 - Gemini s Meteors
Explanation: Taken over the course of an hour shortly after local midnight on December 13, 35 exposures were used to create this postcard from Earth. The composited night scene spans dark skies above the snowy Italian Dolomites during our fair planet's annual Geminid meteor shower. Sirius, alpha star of Canis Major and the brightest star in the night, is grazed by a meteor streak on the right. The Praesepe star cluster, also known as M44 or the Beehive cluster, itself contains about a thousand stars but appears as a smudge of light far above the southern alpine peaks near the top. The shower's radiant is off the top of the frame though, near Castor and Pollux the twin stars of Gemini. The radiant effect is due to perspective as the parallel meteor tracks appear to converge in the distance. As Earth sweeps through the dust trail of asteroid 3200 Phaethon, the dust that creates Gemini's meteors enters Earth's atmosphere traveling at about 22 kilometers per second.

APOD: 2020 November 21 - Mars and Meteor over Jade Dragon Snow Mountain
Explanation: A brilliant yellowish celestial beacon, Mars still dazzles in the night. Peering between clouds the wandering planet was briefly joined by the flash of a meteor in this moonless dark sky on November 18. The single exposure was taken as the Earth swept up dust from periodic comet Tempel-Tuttle during the annual Leonid Meteor Shower. The view of a rugged western horizon looks along the Yulong mountain range in Yunnan province, southwestern China. Yulong (Jade Dragon) Snow Mountain lies below the clouds and beyond the end of the meteor streak.

APOD: 2020 August 17 - Perseids Around the Milky Way
Explanation: Why would meteor trails appear curved? The arcing effect arises only because the image artificially compresses (nearly) the whole sky into a rectangle. The meteors are from the Perseid Meteor Shower that peaked last week. The featured multi-frame image combines not only different directions from the 360 projection, but different times when bright Perseid meteors momentarily streaked across the sky. All Perseid meteors can be traced back to the constellation Perseus toward the lower left, even the seemingly curved (but really straight) meteor trails. Although Perseids always point back to their Perseus radiant, they can appear almost anywhere on the sky. The image was taken from Inner Mongolia, China, where grasslands meet sand dunes. Many treasures also visible in the busy night sky including the central arch of our Milky Way Galaxy, the planets Saturn and Jupiter toward the right, colorful airglow on the central left, and some relatively nearby Earthly clouds. The Perseid Meteor Shower peaks every August.

APOD: 2020 July 23 - Fairytale NEOWISE
Explanation: Comet dust falls through a twilight sky in this dream-like scene, but it's not part of a fairytale movie. Still, Castle Neuschwanstein, nestled in the Bavarian Alps, did inspire Disneyland's Sleeping Beauty Castle. Captured on July 20, the bright streak above the castle towers is likely a Perseid meteor. Though it peaks near mid-August, the annual summer meteor shower is active now. The meteor trail over the fairytale castle can be traced back to the shower's radiant in the heroic constellation Perseus off the top right of the frame. Perseid meteors are produced by dust from periodic Comet Swift-Tuttle. With its own broad dust tail now sweeping through northern skies the celestial apparition above the distant horizon is planet Earth's current darling, Comet NEOWISE.

APOD: 2020 May 14 - Comet Halley vs Comet SWAN
Explanation: The pre-dawn hours of May 3rd were moonless as grains of cosmic dust streaked through southern skies above Reunion Island. Swept up as planet Earth plowed through dusty debris streams left behind periodic Comet 1/P Halley, the annual meteor shower is known as the Eta Aquarids. This inspired exposure captures a bright aquarid meteor flashing left to right over a sea of clouds. The meteor streak points back to the shower's radiant in the constellation Aquarius, well above the eastern horizon and off the top of the frame. Known for speed Eta Aquarid meteors move fast, entering the atmosphere at about 66 kilometers per second, visible at altitudes of 100 kilometers or so. Then about 6 light-minutes from Earth, the pale greenish coma and long tail of Comet C/2020 F8 SWAN were not to be left out of the celestial scene, posing above the volcanic peaks left of center. Now in the northern sky's morning twilight near the eastern horizon Comet SWAN has not become as bright as anticipated though. This first time comet made its closest approach to planet Earth only two days ago and reaches perihelion on May 27.

APOD: 2020 May 12 - Lyrid Meteors from the Constellation Lyra
Explanation: Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Small Harp (Lyra). That is why the famous meteor shower that peaks every April is known as the Lyrids -- the meteors all appear to came from a radiant toward Lyra. In terms of parent body, though, the sand-sized debris that makes up the Lyrid meteors come from Comet Thatcher. The comet follows a well-defined orbit around our Sun, and the part of the orbit that approaches Earth is superposed in front of Lyra. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Lyra. Featured here, a composite image containing over 33 meteors (can you find them all?) from last month's Lyrid meteor shower shows several bright meteors that streaked over a shore of Seč Lake in the Czech Republic. Also visible are the bright stars Vega and Altair, the planet Jupiter, and the central band of our Milky Way Galaxy.

APOD: 2020 April 23 - Lyrid Meteor Streak
Explanation: Earth's annual Lyrid Meteor Shower peaked before dawn yesterday, as our fair planet plowed through debris from the tail of long-period comet Thatcher. In crisp, clear and moonless predawn skies over Brown County, Indiana this streak of vaporizing comet dust briefly shared a telephoto field of view with stars and nebulae along the Milky Way. Alpha star of the constellation Cygnus, Deneb lies near the bright meteor's path along with the region's dark interstellar clouds of dust and the recognizable glow of the North America nebula (NGC 7000). The meteor's streak points back to the shower's radiant, its apparent point of origin on the sky. That would be in the constellation Lyra, near bright star Vega and off the top edge of the frame.

APOD: 2019 October 10 - Mid-Air Meteor and Milky Way
Explanation: On September 24, a late evening commercial flight from Singapore to Australia offered stratospheric views of the southern hemisphere's night sky, if you chose a window seat. In fact, a well-planned seating choice with a window facing toward the Milky Way allowed the set up of a sensitive digital camera on a tripod mount to record the galaxy's central bulge in a series of 10 second long exposures. By chance, one of the exposures caught this bright fireball meteor in the starry frame. Reflected along the wing of the A380 aircraft, the brilliant greenish streak is also internally reflected in the double layer window, producing a fainter parallel to the original meteor track. In the southern sky Jupiter is the bright source beneath the galactic bulge and seen next to a green beacon, just off the wing tip.

APOD: 2019 April 30 - Meteor Misses Galaxy
Explanation: The galaxy was never in danger. For one thing, the Triangulum galaxy (M33), pictured, is much bigger than the tiny grain of rock at the head of the meteor. For another, the galaxy is much farther away -- in this instance 3 million light years as opposed to only about 0.0003 light seconds. Even so, the meteor's path took it angularly below the galaxy. Also the wind high in Earth's atmosphere blew the meteor's glowing evaporative molecule train away from the galaxy, in angular projection. Still, the astrophotographer was quite lucky to capture both a meteor and a galaxy in a single exposure -- which was subsequently added to two other images of M33 to bring up the spiral galaxy's colors. At the end, the meteor was gone in a second, but the galaxy will last billions of years.

APOD: 2019 April 23 - Meteors, Comet, and Big Dipper over La Palma
Explanation: Meteor showers are caused by streams of solid particles, dust size and larger, moving as a group through space. In most cases, the orbits of these meteor streams can be identified with dust expelled from a comet. When the Earth passes through a stream, the particles leave brilliant trails through the night sky as they disintegrate in Earth's atmosphere. The meteor paths are all parallel to each other, but, like train tracks, the effect of perspective causes them to appear to originate from a radiant point in the distance. The featured image composite was taken during January's Quadrantid meteor shower from La Palma, one of Spain's Canary Islands, off the northwest coast of Africa. The Quadrantids radiant is visible just below the handle of the Big Dipper. A careful eye will also discern the faint green coma of Comet Wirtanen. Tonight is the peak of the modest Lyrid meteor shower, with several meteors per hour visible from dark locations with clear skies.

APOD: 2019 January 24 - Matterhorn, Moon, and Meteor
Explanation: Fans of planet Earth probably recognize the Matterhorn in the foreground of this night skyscape. Famed in mountaineering history, the 4,478 meter Alpine mountain stands next to the totally eclipsed Moon. In spite of -22 degree C temperatures, the inspired scene was captured on the morning of January 21 from the mountains near Zermatt, Switzerland. Different exposures record the dim red light reflected by the Moon fully immersed in Earth's shadow. Seen directly above the famous Alpine peak, but about 600 light-years away, are the stars of the Praesepe or Beehive star cluster also known as Messier 44. An added reward to the cold eclipse vigil, a bright and colorful meteor flashed below the temporarily dimmmed Moon, just tracing the Matterhorn's north-eastern climbing route along Hornli ridge.

APOD: 2019 January 14 - Meteor and Milky Way over the Alps
Explanation: Now this was a view with a thrill. From Mount Tschirgant in the Alps, you can see not only nearby towns and distant Tyrolean peaks, but also, weather permitting, stars, nebulas, and the band of the Milky Way Galaxy. What made the arduous climb worthwhile this night, though, was another peak -- the peak of the 2018 Perseids Meteor Shower. As hoped, dispersing clouds allowed a picturesque sky-gazing session that included many faint meteors, all while a carefully positioned camera took a series of exposures. Suddenly, a thrilling meteor -- bright and colorful -- slashed down right next the nearly vertical band of the Milky Way. As luck would have it, the camera caught it too. Therefore, a new image in the series was quickly taken with one of the sky-gazers posing on the nearby peak. Later, all of the images were digitally combined.

APOD: 2018 December 19 - A Rainbow Geminid Meteor
Explanation: Meteors can be colorful. While the human eye usually cannot discern many colors, cameras often can. Pictured is a Geminid captured by camera during last week's meteor shower that was not only impressively bright, but colorful. The radiant grit cast off by asteroid 3200 Phaethon blazed a path across Earth's atmosphere longer than 60 times the angular diameter of the Moon. Colors in meteors usually originate from ionized elements released as the meteor disintegrates, with blue-green typically originating from magnesium, calcium radiating violet, and nickel glowing green. Red, however, typically originates from energized nitrogen and oxygen in the Earth's atmosphere. This bright meteoric fireball was gone in a flash -- less than a second -- but it left a wind-blown ionization trail that remained visible for several minutes, the start of which can be seen here.

APOD: 2018 December 9 - Aurora Shimmer, Meteor Flash
Explanation: Some night skies are serene and passive -- others shimmer and flash. The later, in the form of auroras and meteors, haunted skies over the island of Kvaløya, near Tromsø Norway on 2009 December 13. This 30 second long exposure records a shimmering auroral glow gently lighting the wintery coastal scene. A study in contrasts, the image also captures the sudden flash of a fireball meteor from the excellent Geminid meteor shower of 2009. Streaking past familiar stars in the handle of the Big Dipper, the trail points back toward the constellation Gemini, off the top of the view. Both auroras and meteors occur in Earth's upper atmosphere at altitudes of 100 kilometers or so, but aurora caused by energetic charged particles from the magnetosphere, while meteors are trails of cosmic dust. Nine years after this photograph was taken, toward the end of this week, the yearly 2018 Geminids meteor shower will peak again, although this time their flashes will compete with the din of a half-lit first-quarter moon during the first half of the night.

APOD: 2018 November 23 - Good Morning Leonid
Explanation: On November 17, just an hour before sunrise, this bright and colorful meteor flashed through clear predawn skies. Above a sea of clouds this striking autumn morning's moment was captured from Hochblauen, a prominent 1165 meter high summit in southern Germany's Black Forest. Shining through the twilight, Sirius as well as the familiar stars of Orion are recognizable near the southwestern horizon, and the meteor seems headed right for the hunter's belt and sword. Still, as part of the annual Leonid meteor shower, the meteor trail does point back to the shower's radiant. The constellation Leo is high above the horizon and off the top left of the frame.

APOD: 2018 October 30 - Orionids Meteors over Inner Mongolia
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 two dozen meteors were caught in successively added exposures last October 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. An Orionids image featured on APOD one year ago today from the same location shows the same car. Next month, the Leonids Meteor Shower from Comet Tempel-Tuttle should also result in some bright meteor streaks.

APOD: 2018 October 21 - Meteor, Comet, and Seagull (Nebula)
Explanation: A meteor, a comet, and a photogenic nebula have all been captured in this single image. The closest and most fleeting is the streaking meteor on the upper right -- it was visible for less than a second. The meteor, which disintegrated in Earth's atmosphere, was likely a small bit of debris from the nucleus of Comet 21P/Giacobini-Zinner, coincidentally the comet captured in the same image. Comet 21P, pictured across the inner Solar System from Earth, is distinctive for its long dust tail spread horizontally across the image center. This comet has been visible with binoculars for the past few months but is now fading as it heads back out to the orbit of Jupiter. Farthest out at 3,500 light years distant is the IC 2177, the Seagull Nebula, visible on the left. The comparatively vast Seagull Nebula, with a wingspan on order 250 light-years, will likely remain visible for hundreds of thousands of years. Long exposures, taken about two weeks ago from Iwaki-City in Japan, were combined to capture the image's faintest elements. You, too, could see a meteor like this -- and perhaps sooner than you might think: tonight is the peak of the Orionids meteor shower.

APOD: 2018 October 8 - Comet 21P Between Rosette and Cone Nebulas
Explanation: Small bits of this greenish-gray comet are expected to streak across Earth's atmosphere tonight. Specifically, debris from the eroding nucleus of Comet 21P / Giacobini-Zinner, pictured, causes the annual Draconids meteor shower, which peaks this evening. Draconid meteors are easy to enjoy this year because meteor rates will likely peak soon after sunset with the Moon's glare nearly absent. Patience may be needed, though, as last month's passing of 21P near the Earth's orbit is not expected to increase the Draconids' normal meteor rate this year of (only) a few meteors per hour. Then again, meteor rates are notoriously hard to predict, and the Draconids were quite impressive in 1933, 1946, and 2011. Featured, Comet 21P gracefully posed between the Rosette (upper left) and Cone (lower right) nebulas two weeks ago before heading back out to near the orbit of Jupiter, to return again in about six and a half years.

APOD: 2018 September 15 - Mont Blanc, Meteor, and Milky Way
Explanation: Snowy Mont Blanc is near the center of this atmospheric night skyscape. But high, thin clouds fogged the skies at the photographer's location, looking south toward Europe's highest peak from the southern Swiss Alps. Still, the 13 second exposure finds the faint star fields and dark rifts of the Milky Way above the famous white mountain. Bloated by the mist, bright planet Saturn and Antares (right), alpha star of Scorpius, shine through the clouds to flank the galaxy's central bulge. The high-altitude scene is from the rewarding night of August 12/13, so it also includes the green trail of a Perseid meteor shooting along the galactic plane.

APOD: 2018 September 8 - Real Time Perseid
Explanation: Bright meteors and dark night skies made this year's Perseid meteor shower a great time for a weekend campout. And while packing away their equipment, skygazers at a campsite in the mountains of southern Germany found at least one more reason to linger under the stars, witnessing this brief but colorful flash with their own eyes. Presented as a 50 frame gif, the two second long video was captured during the morning twilight of August 12. In real time it shows the development of the typical green train of a bright Perseid meteor. A much fainter Perseid is just visible farther to the right. Plowing through Earth's atmosphere at 60 kilometers per second, Perseids are fast enough to excite the characteristic green emission of atomic oxygen at altitudes of 100 kilometers or so.

APOD: 2018 August 17 - Perseid Fireball and Persistent Train
Explanation: Before local midnight on August 12, this brilliant Perseid meteor flashed above the Poloniny Dark Sky Park, Slovakia, planet Earth. Streaking beside the summer Milky Way, its initial color is likely due to the shower meteor's characteristically high speed. Moving at about 60 kilometers per second, Perseid meteors can excite green emission from oxygen atoms while passing through the thin atmosphere at high altitudes. Also characteristic of bright meteors, this Perseid left a lingering visible trail known as a persistent train, wafting in the upper atmosphere. Its development is followed in the inset frames, exposures separated by one minute and shown at the scale of the original image. Compared to the brief flash of the meteor, the wraith-like trail really is persistent. After an hour faint remnants of this one could still be traced, expanding to over 80 degrees on the sky.

APOD: 2018 August 16 - Parker vs Perseid
Explanation: The brief flash of a bright Perseid meteor streaks across the upper right in this composited series of exposures made early Sunday morning near the peak of the annual Perseid meteor shower. Set up about two miles from Space Launch Complex 37 at Cape Canaveral Air Force Station, the photographer also captured the four minute long trail of a Delta IV Heavy rocket carrying the Parker Solar Probe into the dark morning sky. Perseid meteors aren't slow. The grains of dust from periodic comet Swift-Tuttle vaporize as they plow through Earth's upper atmosphere at about 60 kilometers per second (133,000 mph). On its way to seven gravity-assist flybys of Venus over its seven year mission, the Parker Solar Probe's closest approach to the Sun will steadily decrease, finally reaching a distance of 6.1 million kilometers (3.8 million miles). That's about 1/8 the distance between Mercury and the Sun, and within the solar corona, the Sun's tenuous outer atmosphere. By then it will be traveling roughly 190 kilometers per second (430,000 mph) with respect to the Sun, a record for fastest spacecraft from planet Earth.

APOD: 2018 August 12 - Meteor before Galaxy
Explanation: What's that green streak in front of the Andromeda galaxy? A meteor. While photographing the Andromeda galaxy in 2016, near the peak of the Perseid Meteor Shower, a sand-sized rock from deep space crossed right in front of our Milky Way Galaxy's far-distant companion. The small meteor took only a fraction of a second to pass through this 10-degree field. The meteor flared several times while braking violently upon entering Earth's atmosphere. The green color was created, at least in part, by the meteor's gas glowing as it vaporized. Although the exposure was timed to catch a Perseids meteor, the orientation of the imaged streak seems a better match to a meteor from the Southern Delta Aquariids, a meteor shower that peaked a few weeks earlier. Not coincidentally, the Perseid Meteor Shower peaks again tonight.

APOD: 2018 August 8 - Animation: Perseid Meteor Shower
Explanation: Where do Perseid meteors come from? Mostly small bits of stony grit, Perseid meteoroids were once expelled from Comet Swift-Tuttle and continue to follow this comet's orbit as they slowly disperse. The featured animation depicts the entire meteoroid stream as it orbits our Sun. When the Earth nears this stream, as it does every year, the Perseid Meteor Shower occurs. Highlighted as bright in the animation, comet debris this size is usually so dim it is practically undetectable. Only a small fraction of this debris will enter the Earth's atmosphere, heat up and disintegrate brightly. This weekend promises some of the better skies to view the Perseid shower as well as other active showers because the new moon will not only be faint, it will be completely absent from the sky for most of the night. Although not outshining faint Perseids, the new moon will partially obstruct the Sun as a partial solar eclipse will be visible from some northern locations.

APOD: 2018 April 22 - Meteor Over Crater Lake
Explanation: Did you see it? One of the more common questions during a meteor shower occurs because the time it takes for a meteor to flash is typically less than the time it takes for a head to turn. Possibly, though, the glory of seeing bright meteors shoot across and knowing that they were once small granules on another world might make it all worthwhile, even if your observing partner(s) could not share in every particular experience. Peaking late tonight, a dark sky should enable the Lyrids meteor shower to exhibit as many as 20 visible meteors per hour from some locations. In the featured composite of nine exposures taken during the 2012 shower, a bright Lyrid meteor streaks above picturesque Crater Lake in Oregon, USA. Snow covers the foreground, while the majestic central band of our home galaxy arches well behind the serene lake. Other meteor showers this year -- and every year -- include the Perseids in mid-August and the Leonids in mid-November.

APOD: 2017 December 23 - Phaethon's Brood
Explanation: Based on its well-measured orbit, 3200 Phaethon (sounds like FAY-eh-thon) is recognized as the source of the meteroid stream responsible for the annual Geminid meteor shower. Even though most meteor showers' parents are comets, 3200 Phaethon is a known and closely tracked near-Earth asteroid with a 1.4 year orbital period. Rocky and sun-baked, its perihelion or closest approach to the Sun is well within the orbit of innermost planet Mercury. In this telescopic field of view, the asteroid's rapid motion against faint background stars of the heroic constellation Perseus left a short trail during the two minute total exposure time. The parallel streaks of its meteoric children flashed much more quickly across the scene. The family portrait was recorded near the Geminid meteor shower's very active peak on December 13. That was just before 3200 Phaethon's historic December 16 closest approach to planet Earth.

APOD: 2017 December 15 - Geminids of the North
Explanation: Earth's annual Geminid meteor shower did not disappoint as our fair planet plowed through dust from active asteroid 3200 Phaethon. Captured in this northern hemisphere nightscape, the meteors stream away from the shower's radiant in Gemini. To create the image, 37 individual frames recording meteor streaks were taken over period of 8.5 hours during the night of December 12/13. In the final composite they were selected and registered against the starry sky above a radio telescope dish of MUSER, a solar-dedicated radio telescope array at astronomically-named Mingantu Station in Inner Mongolia, China, about 400 kilometers from Beijing. Sirius, alpha star of Canis Major, shines brightly just above the radio dish and the Milky Way stretches toward the zenith. Yellowish Betelgeuse is a standout in Orion to the right of the northern Milky Way. The shower's radiant is at top left, high above the horizon near Castor and Pollux the twin stars of Gemini. The radiant effect is due to perspective as the parallel meteor tracks appear to converge in the distance. Gemini's meteors enter Earth's atmosphere traveling at about 22 kilometers per second.

APOD: 2017 December 13 - Meteors over Inner Mongolia
Explanation: Did you ever get caught in a meteor shower? If yes, then every minute or so the sky sparked with fleeting flashes of light. This was the fate of the pictured astrophotographer during last year's Perseids meteor shower. During the featured three-hour image composite, about 90 Perseids rained down above Lake Duolun of Inner Mongolia, China. If you trace back the meteor streaks, you will find that most of them appear to radiate from a single constellation -- in this case Perseus. In fact, you can even tell which meteors are not Perseids because they track differently. Tonight promises to be another good night to get caught in a meteor shower because it is the peak for the Geminids. Gemini, the shower radiant, should rise shortly after sunset and be visible most of the night.

APOD: 2017 November 17 - Major Fireball Meteor
Explanation: The sky glows with soft pinkish colors of fading twilight in this serendipitous mountaintop vista. Taken in subfreezing temperatures, the thoughtfully composed photo shows snowy, rugged peaks seen from a mountain pass on November 14. Below lies the village of La Villa, Alta Badia in Italy's Dolomite Alps. Above the nestled village lights, the constellation Ursa Major hangs over the northern horizon. But most stunning is the intense fireball meteor. It was captured during the camera's exposure by chance as it flashed east to west across the northern horizon, under Ursa Major's familiar Big Dipper asterism. In fact, sightings of this major fireball meteor were widely reported in European skies, the most reported fireball event ever for planet Earth's American Meteor Society and the International Meteor Organization. The meteor's measured track over Germany is consistent with its origin near the active radiant of November's Taurid Meteor Shower. Taurid meteors are associated with dust from Encke's comet.

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 August 6 - Milky Way and Exploding Meteor
Explanation: Next weekend the Perseid Meteor Shower reaches its maximum. Grains of icy rock will streak across the sky as they evaporate during entry into Earth's atmosphere. These grains were shed from Comet Swift-Tuttle. The Perseids result from the annual crossing of the Earth through Comet Swift-Tuttle's orbit, and are typically the most active meteor shower of the year. Although it is hard to predict the level of activity in any meteor shower, in a clear dark sky an observer might see a meteor a minute. This year's Perseids peak nearly a week after full Moon, and so some faint meteors will be lost to the lunar skyglow. Meteor showers in general are best be seen from a relaxing position, away from lights. Featured here is a meteor caught exploding during the 2015 Perseids above Austria next to the central band of our Milky Way Galaxy.

APOD: 2017 August 1 - Perseid Meteors over Turkey
Explanation: The Perseid Meteor Shower, usually the best meteor shower of the year, will peak late next week. A person watching a clear sky from a dark location might see a bright meteor every minute. These meteors are actually specks of rock that have broken off Comet Swift-Tuttle and continued to orbit the Sun until they vaporize in Earth's atmosphere. The featured composite image shows a outburst of Perseids as they appeared over Turkey during last year's meteor shower. Enough meteors were captured to trace the shower's radiant back to the constellation of Perseus on the far left. The tail-end of the Perseids will still be going during the total solar eclipse on August 21, creating a rare opportunity for some lucky astrophotographers to image a Perseid meteor during the day.

APOD: 2017 April 27 - Lyrids in Southern Skies
Explanation: Earth's annual Lyrid meteor shower peaked before dawn on April 22nd, as our fair planet plowed through dust from the tail of long-period comet Thatcher. Seen from the high, dark, and dry Atacama desert a waning crescent Moon and brilliant Venus join Lyrid meteor streaks in this composited view. Captured over 5 hours on the night of April 21/22, the meteors stream away from the shower's radiant, a point not very far on the sky from Vega, alpha star of the constellation Lyra. The radiant effect is due to perspective as the parallel meteor tracks appear to converge in the distance. In the foreground are domes of the Las Campanas Observatory housing (left to right) the 2.5 meter du Pont Telescope and the 1.3 meter Optical Gravitational Lensing Experiment (OGLE) telescope.

APOD: 2016 September 5 - Spiral Meteor through the Heart Nebula
Explanation: What is this meteor doing? Dynamically, the unusually short and asymmetric train may indicate that the sand-sized grain at the center of the glow is momentarily spinning as it ablates, causing its path to be slightly spiral. Geographically, the meteor appears to be going through the Heart Nebula, although really it is in Earth's atmosphere and so is about one quadrillion times closer. Taken last month on the night of the peak, this meteor is likely from the Perseid meteor shower. The Perseids radiant, in the constellation of Perseus, is off the frame to the upper right, toward the direction that the meteor streak is pointing. The Heart Nebula was imaged in 18 one-minute exposures, of which the unusual meteor streak appeared on just one. The meteor train is multicolored as its glow emanates from different elements in the heated gas.

APOD: 2016 August 20 - Gamma rays and Comet Dust
Explanation: Gamma-rays and dust from periodic Comet Swift-Tuttle plowed through planet Earth's atmosphere on the night of August 11/12. Impacting at about 60 kilometers per second the grains of comet dust produced this year's remarkably active Perseid meteor shower. This composite wide-angle image of aligned shower meteors covers a 4.5 hour period on that Perseid night. In it the flashing meteor streaks can be traced back to the shower's origin on the sky. Alongside the Milky Way in the constellation Perseus, the radiant marks the direction along the perodic comet's orbit. Traveling at the speed of light, cosmic gamma-rays impacting Earth's atmosphere generated showers too, showers of high energy particles. Just as the meteor streaks point back to their origin, the even briefer flashes of light from the particles can be used to reconstruct the direction of the particle shower, to point back to the origin on the sky of the incoming gamma-ray. Unlike the meteors, the incredibly fast particle shower flashes can't be followed by eye. But both can be followed by the high speed cameras on the multi-mirrored dishes in the foreground. Of course, the dishes are MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescopes, an Earth-based gamma-ray observatory on the Canary Island of La Palma.

APOD: 2016 August 17 - Meteor before Galaxy
Explanation: What's that green streak in front of the Andromeda galaxy? A meteor. While photographing the Andromeda galaxy last Friday, near the peak of the Perseid Meteor Shower, a sand-sized rock from deep space crossed right in front of our Milky Way Galaxy's far-distant companion. The small meteor took only a fraction of a second to pass through this 10-degree field. The meteor flared several times while braking violently upon entering Earth's atmosphere. The green color was created, at least in part, by the meteor's gas glowing as it vaporized. Although the exposure was timed to catch a Perseids meteor, the orientation of the imaged streak seems a better match to a meteor from the Southern Delta Aquariids, a meteor shower that peaked a few weeks earlier.

APOD: 2016 August 13 - Perseid from Torralba del Burgo
Explanation: Perseid meteors rained on planet Earth last night. This year the stream of dust from periodic comet Swift-Tuttle has produced a stunningly active shower of bright cosmic streaks. In this 25 second long exposure, one luminous Perseid trail, fast and colorful with a small explosion at the end, is witnessed by night skygazers from Torralba del Burgo, Soria, Spain. A second fainter meteor trail appears well below the first. The two can be extended to intersect at the meteor shower's radiant just above the brighter stars of the heroic constellation Perseus. Though the meteor shower's activity is waning, in the coming days Perseids will still flash through the night. But you won't see any if you don't go outside and look up.

APOD: 2015 December 17 - Geminids of the South
Explanation: Earth's annual Geminid meteor shower did not disappoint, peaking before dawn on December 14 as our fair planet plowed through dust from active asteroid 3200 Phaethon. Captured in this southern hemisphere nightscape the meteors stream away from the shower's radiant in Gemini. To create the image, many individual frames recording meteor streaks were taken over period of 5 hours. In the final composite they were selected and registered against the starry sky above the twin 6.5 meter Magellan telescopes of Carnegie Las Campanas Observatory in Chile. Rigel in Orion, and Sirius shine brightly as the Milky Way stretches toward the zenith. Near Castor and Pollux the twin stars of Gemini, the meteor shower's radiant is low, close to the horizon. The radiant effect is due to perspective as the parallel meteor tracks appear to converge in the distance. Gemini's meteors enter Earth's atmosphere traveling at about 22 kilometers per second.

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 August 25 - Meteors and Milky Way over Mount Rainier
Explanation: Despite appearances, the sky is not falling. Two weeks ago, however, tiny bits of comet dust were. Featured here is the Perseids meteor shower as captured over Mt. Rainier, Washington, USA. The image was created from a two-hour time lapse video, snaring over 20 meteors, including one that brightened dramatically on the image left. Although each meteor train typically lasts less than a second, the camera was able to capture their color progressions as they disintegrated in the Earth's atmosphere. Here an initial green tint may be indicative of small amounts of glowing magnesium atoms that were knocked off the meteor by atoms in the Earth's atmosphere. To cap things off, the central band of our Milky Way Galaxy was simultaneously photographed rising straight up behind the snow-covered peak of Mt. Rainier. Another good meteor shower is expected in mid-November when debris from a different comet intersects Earth as the Leonids.

APOD: 2015 August 13 - Moonless Meteors and the Milky Way
Explanation: Have you watched the Perseid meteor shower? Though the annual shower's predicted peak was last night, meteor activity should continue tonight (August 13/14), best enjoyed by just looking up in clear, dark skies after midnight. Of course, this year's Perseid shower has the advantage of being active near the August 14 New Moon. Since the nearly New Moon doesn't rise before the morning twilight many fainter meteors are easier to spot until then, with no interference from bright moonlight. The Perseid meteor shower last occurred near a New Moon in 2013. That's when the exposures used to construct this image were made, under dark, moonless skies from Hvar Island off the coast of Croatia. The widefield composite includes 67 meteors streaming from the heroic constellation Perseus, the shower's radiant, captured during 2013 August 8-14 against a background of faint zodiacal light and the Milky Way. The next moonless Perseid meteor shower will be in August 2018.

APOD: 2015 August 12 - Milky Way and Exploding Meteor
Explanation: Tonight the Perseid Meteor Shower reaches its maximum. Grains of icy rock will streak across the sky as they evaporate during entry into Earth's atmosphere. These grains were shed from Comet Swift-Tuttle. The Perseids result from the annual crossing of the Earth through Comet Swift-Tuttle's orbit, and are typically the most active meteor shower of the year. Although it is hard to predict the level of activity in any meteor shower, in a clear dark sky an observer might see a meteor a minute. This year's Perseids occur just before a new Moon and so the relatively dark sky should make even faint meteors visible. Meteor showers in general are best be seen from a relaxing position, away from lights. Featured here is a meteor caught exploding two weeks ago above Austria next to the central band of our Milky Way Galaxy.

APOD: 2015 April 23 - Meteor in the Milky Way
Explanation: Earth's April showers include the Lyrid Meteor Shower, observed for more than 2,000 years when the planet makes its annual passage through the dust stream of long-period Comet Thatcher. A grain of that comet's dust, moving 48 kilometers per second at an altitude of 100 kilometers or so, is swept up in this night sky view from the early hours of April 21. Flashing toward the southeastern horizon, the meteor's brilliant streak crosses the central region of the rising Milky Way. Its trail points back toward the shower's radiant in the constellation Lyra, high in the northern springtime sky and off the top of the frame. The yellowish hue of giant star Antares shines to the right of the Milky Way's bulge. Higher still is bright planet Saturn, near the right edge. Seen from Istra, Croatia, the Lyrid meteor's greenish glow reflects in the waters of the Adriatic Sea.

APOD: 2014 December 7 - Aurora Shimmer Meteor Flash
Explanation: Northern Lights, or aurora borealis, haunted skies over the island of Kvaløya, near Tromsø Norway on 2009 December 13. This 30 second long exposure records their shimmering glow gently lighting the wintery coastal scene. A study in contrasts, it also captures the sudden flash of a fireball meteor from the excellent Geminid meteor shower in 2009 December. Streaking past familiar stars in the handle of the Big Dipper, the trail points back toward the constellation Gemini, off the top of the view. Both aurora and meteors occur in Earth's upper atmosphere at altitudes of 100 kilometers or so, but aurora caused by energetic charged particles from the magnetosphere, while meteors are trails of cosmic dust. Toward the end of this week the 2014 Geminids meteor shower will peak, although they will compete with the din of last quarter moonlight.

APOD: 2014 November 16 - Leonids Above Torre de la Guaita
Explanation: Leonids Meteor Shower came to an impressive crescendo in 1999. Observers in Europe saw a sharp peak in the number of meteors visible around 0210 UTC during the early morning hours of November 18. Meteor counts then exceeded 1000 per hour - the minimum needed to define a true meteor storm. At other times and from other locations around the world, observers typically reported respectable rates of between 30 and 100 meteors per hour. This photograph is a 20-minute exposure ending just before the main Leonids peak began. Visible are at least five Leonid meteors streaking high above the Torre de la Guaita, an observation tower used during the 12th century in Girona, Spain. In 2014, over the next few nights, the Leonids meteor shower will again peak. This year, although the crescent Moon should not create much competing skyglow, the Earth is predicted to pass through a more moderate stream of debris left over from Comet Tempel-Tuttle than in 1999, perhaps resulting in as many as 15 visible meteors per hour from dark locations.

APOD: 2014 August 10 - A Perseid Below
Explanation: Denizens of planet Earth typically watch meteor showers by looking up. But this remarkable view, captured on August 13, 2011 by astronaut Ron Garan, caught a Perseid meteor by looking down. From Garan's perspective onboard the International Space Station orbiting at an altitude of about 380 kilometers, the Perseid meteors streak below, swept up dust left from comet Swift-Tuttle heated to incandescence. The glowing comet dust grains are traveling at about 60 kilometers per second through the denser atmosphere around 100 kilometers above Earth's surface. In this case, the foreshortened meteor flash is right of frame center, below the curving limb of the Earth and a layer of greenish airglow, just below bright star Arcturus. Want to look up at a meteor shower? You're in luck, as the 2014 Perseids meteor shower peaks this week. Unfortunately, the fainter meteors in this year's shower will be hard to see in a relatively bright sky lit by the glow of a nearly full Moon.

APOD: 2014 April 24 - Lyrids in Southern Skies
Explanation: Earth's annual Lyrid meteor shower peaked before dawn on April 22nd, as our fair planet plowed through dust from the tail of long-period comet Thatcher. Even in the dry and dark Atacama desert along Chile's Pacific coast, light from a last quarter Moon made the night sky bright, washing out fainter meteor streaks. But brighter Lyrid meteors still put on a show. Captured in this composited earth-and-sky view recorded during early morning hours, the meteors stream away from the shower's radiant near Vega, alpha star of the constellation Lyra. The radiant effect is due to perspective as the parallel meteor tracks appear to converge in the distance. Rich starfields and dust clouds of our own Milky Way galaxy stretch across the background.

APOD: 2014 February 12 - Rocket, Meteor, and Milky Way over Thailand
Explanation: Can the night sky appear both serene and surreal? Perhaps classifiable as serene in the above panoramic image taken last Friday are the faint lights of small towns glowing across a dark foreground landscape of Doi Inthanon National Park in Thailand, as well as the numerous stars glowing across a dark background starscape. Also visible are the planet Venus and a band of zodiacal light on the image left. Unusual events are also captured, however. First, the central band of our Milky Way Galaxy, while usually a common sight, appears here to hover surreally above the ground. Next, a fortuitous streak of a meteor was captured on the image right. Perhaps the most unusual component is the bright spot just to the left of the meteor. That spot is the plume of a rising Ariane 5 rocket, launched a few minutes before from Kourou, French Guiana. How lucky was the astrophotographer to capture the rocket launch in his image? Pretty lucky -- the image was not timed to capture the rocket. Also lucky was how photogenic -- and perhaps surreal -- the rest of the sky turned out to be.

APOD: 2013 December 17 - Geminid Meteors over Teide Volcano
Explanation: On some nights it rains meteors. Peaking two nights ago, asteroid dust streaked through the dark skies of Earth, showering down during the annual Geminids meteor shower. Astrophotographer Juan Carlos Casado captured the space weather event, as pictured above, in a series of exposures spanning about 2.3 hours using a wide angle lens. The snowcapped Teide volcano of the Canary Islands of Spain towers in the foreground, while the picturesque constellation of Orion highlights the background. The star appearing just near the top of the volcano is Rigel. Although the asteroid dust particles are traveling parallel to each other, the resulting meteor streaks appear to radiate from a single point on the sky, in this case in the constellation of Gemini, off the top of the image. Like train tracks appearing to converge in the distance, the meteor radiant effect is due to perspective. The astrophotographer has estimated that there are about 50 Geminids visible in the above composite image -- how many do you see?

APOD: 2013 December 13 - Geminid Meteor Shower over Dashanbao Wetlands
Explanation: The annual Geminid meteor shower is raining down on planet Earth this week. Despite the waxing gibbous moonlight, the reliable Geminids should be enjoyable tonight (night of December 13/14) near the shower's peak. Recorded near last year's peak in the early hours of December 14, 2012, this skyscape captures many of Gemini's lovely shooting stars. The careful composite of exposures was made during a three hour period overlooking the Dashanbao Wetlands in central China. Dark skies above are shared with bright Jupiter (right), Orion, (right of center) and the faint band of the Milky Way. The shower's radiant in the constellation Gemini, the apparent source of all the meteor streaks, lies just above the top of the frame. Dust swept up from the orbit of active asteroid 3200 Phaethon, Gemini's meteors enter the atmosphere traveling at about 22 kilometers per second.

APOD: 2013 August 21 - Perseid Meteors Over China
Explanation: Comet dust rained down on planet Earth earlier this month, streaking through dark skies in the annual Perseid meteor shower. While enjoying the anticipated space weather above Zhangbei Prairie, Hebei Province, China, astronomer Xiang Zhan recorded a series of 10 second long exposures spanning four hours on the night of August 12/13 using a wide angle lens. Combining frames which captured 68 meteor flashes, he produced the above composite view of the Perseids of summer. Although the sand-sized comet particles are traveling parallel to each other, the resulting shower meteors clearly seem to radiate from a single point on the sky in the eponymous constellation Perseus. The radiant effect is due to perspective, as the parallel tracks appear to converge at a distance. The next notable meteor shower may be the Orionids in late October.

APOD: 2013 June 15 - Delphinid Meteor Mystery
Explanation: Over a five hour period last Tuesday morning, exposures captured this tantalizing view of meteor streaks and the Milky Way in dark skies above Las Campanas Observatory in Chile. During that time, astronomers had hoped to see an outburst from the gamma Delphinid meteor shower as Earth swept through the dust trail left by an unknown comet. Named for the shower's radiant point in the constellation Delphinus, a brief but strong outburst was reported in bright, moonlit skies on June 10, 1930. While no strong Delphinid meteor activity was reported since, an outburst was tentatively predicted to occur again in 2013. But even though Tuesday's skies were dark, the overall rate of meteors in this field is low, and only the three lower meteor streaks seem to point back to the shower's estimated radiant.

APOD: 2013 February 23 - Chelyabinsk Meteor Flash
Explanation: A meteoroid fell to Earth on February 15, streaking some 20 to 30 kilometers above the city of Chelyabinsk, Russia at 9:20am local time. Initially traveling at about 20 kilometers per second, its explosive deceleration after impact with the lower atmosphere created a flash brighter than the Sun. This picture of the brilliant bolide (and others of its persistent trail) was captured by photographer Marat Ametvaleev, surprised during his morning sunrise session creating panoramic images of the nearby frosty landscape. An estimated 500 kilotons of energy was released by the explosion of the 17 meter wide space rock with a mass of 7,000 to 10,000 tons. Actually expected to occur on average once every 100 years, the magnitude of the Chelyabinsk event is the largest known since the Tunguska impact in 1908.

APOD: 2013 February 18 - The Great Russian Meteor of 2013
Explanation: What in heaven's blazes is that? Thousands of people living near the Ural Mountains in Russia saw last Friday morning one of the more spectacular meteors of modern times streak across the sky. Forceful sound waves arrived at the ground minutes later, knocking people over and breaking windows for hundreds of kilometers. The above video is a compilation of several car dashcams and includes real time footage of the meteor rampaging, smoke trails drifting, shadows quickly shifting, and even the meteor's light reflecting off the back of a bus. The fireball is thought to have been caused by a car-sized chunk of ice and rock crashing into the Earth's atmosphere. Since the event was captured from so many angles, the meteor's trajectory has become determined well enough to indicate from where it came and to where any resultant pieces might have landed. It is already certain that this meteor had nothing to do with the several-times larger asteroid 2012 DA14 which passed the Earth from a different direction later the same day. If pieces of the meteor are found, they might tell humanity more about the early Solar System, when the meteor was likely formed.

APOD: 2013 February 9 - The Great Meteor Procession of 1913
Explanation: One hundred years ago today the Great Meteor Procession of 1913 occurred, a sky event described by some as "magnificent" and "entrancing" and which left people feeling "spellbound" and "privileged". Because one had to be in a right location, outside, and under clear skies, only about 1,000 people noted seeing the procession. Lucky sky gazers -- particularly those near Toronto, Canada -- had their eyes drawn to an amazing train of bright meteors streaming across the sky, in groups, over the course of a few minutes. A current leading progenitor hypothesis is that a single large meteor once grazed the Earth's atmosphere and broke up. When the resulting pieces next encountered the Earth, they came in over south-central Canada, traveled thousands of kilometers as they crossed over the northeastern USA, and eventually fell into the central Atlantic ocean. Pictured above is a digital scan of a halftone hand-tinted image by the artist Gustav Hahn who was fortunate enough to witness the event first hand. Although nothing quite like the Great Meteor Procession of 1913 has been reported since, numerous bright fireballs -- themselves pretty spectacular -- have since been recorded, some even on video.

APOD: 2012 November 19 - Leonids Over Monument Valley
Explanation: What's happening in the sky over Monument Valley? A meteor shower. Over the past weekend the Leonid meteor shower has been peaking. The image -- actually a composite of six exposures of about 30 seconds each -- was taken in 2001, a year when there was a much more active Leonids shower. At that time, Earth was moving through a particularly dense swarm of sand-sized debris from Comet Tempel-Tuttle, so that meteor rates approached one visible streak per second. The meteors appear parallel because they all fall to Earth from the meteor shower radiant -- a point on the sky towards the constellation of the Lion (Leo). Although the predicted peak of this year's Leonid meteor shower is over, another peak may be visible early tomorrow morning. By the way -- how many meteors can you identify in the above image?

APOD: 2012 November 12 - Meteor and Moonbow over Wallaman Falls
Explanation: Which feature takes your breath away first in this encompassing panorama of land and sky? The competition is strong with a waterfall, meteor, starfield, and even a moonbow all vying for attention. It is interesting to first note, though, what can't be seen -- a rising moon on the other side of the camera. The bright moon not only illuminated this beautiful landscape in Queensland, Australia last June, but also created the beautiful moonbow seen in front of Wallaman Falls. Just above the ridge in the above image is the horizontal streak of an airplane. Toward the top of the frame is the downward streak of a bright meteor, a small pebble from across our Solar System that lit up as it entered the Earth's atmosphere. Well behind the meteor are numerous bright stars and nebula seen toward the center of our Galaxy. Finally, far in the background, is the band of our Milky Way Galaxy, running diagonally from the lower left to the upper right in the image but also circling the entire sky.

APOD: 2012 August 25 - Perseid over Albrechtsberg Castle
Explanation: Medieval Albrechtsberg castle is nestled in trees near the northern bank of the river Pielach and the town of Melk, Austria. In clearing night skies on August 12 it stood under constellations of the northern summer, including Aquarius, Aquila, and faint, compact Delphinus (above and right of center) in this west-looking skyview. The scene also captures a bright meteor above the castle walls. Part of the annual perseid meteor shower, its trail points back toward the heroic constellation Perseus high above the horizon in the early morning hours. Entering the atmosphere at about 60 kilometers per second, perseid meteors are swept up dust grains from the tail of comet Swift-Tuttle.

APOD: 2012 August 10 - Perseid Below
Explanation: Denizens of planet Earth watched last year's Perseid meteor shower by looking up into the bright moonlit night sky. But this remarkable view captured on August 13, 2011 by astronaut Ron Garan looks down on a Perseid meteor. From Garan's perspective onboard the International Space Station orbiting at an altitude of about 380 kilometers, the Perseid meteors streak below, swept up dust left from comet Swift-Tuttle heated to incandescence. The glowing comet dust grains are traveling at about 60 kilometers per second through the denser atmosphere around 100 kilometers above Earth's surface. In this case, the foreshortened meteor flash is right of frame center, below the curving limb of the Earth and a layer of greenish airglow, just below bright star Arcturus. Want to look up at this year's Perseid meteor shower? You're in luck. This weekend the shower should be near its peak, with less interference from a waning crescent Moon rising a few hours before the Sun.

APOD: 2012 April 28 - Sutter's Mill Meteorite
Explanation: Last Sunday's bright fireball meteor falling through skies over California and Nevada produced sonic booms over a broad area around 7:51 am. Estimates indicate the meteor was about the size of a minivan. Astronomer Peter Jenniskens subsequently recovered these fragments of a crushed 4 gram meteorite, the second find from this meteor fall, in the parking lot of the Henningsen-Lotus state park, not far from Sutter's Mill. This is now known as the Sutter's Mill Meteorite, the location famous for its association with the California Gold Rush. The meteorite may well be astronomer's gold too, thought to be a rare CM type carbonaceous chondrite, a type rich in organic compounds and similar to the Murchison Meteorite. To trace the meteor's orbit, details of its breakup, and aid in locating more fragements, scientists are also searching for video records. Security cameras across a wide area could have accidently captured the fireball event near 7:51 am PDT on April 22; e.g. California (SF Bay Area, Los Angeles, near Redding) and Nevada (Reno area, Tonopah), even in southern parts of Oregon and near Salt Lake City in Utah. If you have video footage of the event, please use the contact information here.

APOD: 2012 April 25 - Meteor Over Crater Lake
Explanation: Did you see it? One of the more common questions during a meteor shower occurs because the time it takes for a meteor to flash is typically less than the time it takes for a head to turn. Possibly, though, the glory of seeing bright meteors shoot across and knowing that they were once small pebbles on another world might make it all worthwhile, even if your observing partner(s) could not share in every particular experience. Peaking over the past few days, a dark moonless sky allowed the Lyrids meteor shower to exhibit as many as 30 visible meteors per hour from some locations. A bright Lyrid meteor streaks above picturesque Crater Lake in Oregon, USA, in the above composite of nine exposures taken last week. Snow covers the foreground, while the majestic central band of our home galaxy arches well behind the serene lake. Other meteor showers this year include the Perseids in mid-August and the Leonids in mid-November, both expected to also dodge the glare of a bright Moon in 2012.

APOD: 2012 January 8 - Lighthouse and Meteor
Explanation: Named for a forgotten constellation, the Quadrantid Meteor Shower is an annual event for planet Earth's northern hemisphere skygazers. It usually peaks briefly in the cold, early morning hours of January 4. The shower's radiant point on the sky lies within the old, astronomically obsolete constellation Quadrans Muralis. That position is situated near the boundaries of the modern constellations Hercules, Bootes, and Draco. Many of this year's Quadrantid meteors were dim, but the one captured in this north-looking view is bright and easy to spot. In the foreground is the Maurice River's East Point Lighthouse located near the southern tip of New Jersey on the US east coast. The likely source of the dust stream that produces Quadrantid meteors was identified in 2003 as an asteroid.

APOD: 2011 December 19 - A Geminid Meteor Over Iran
Explanation: Some beautiful things begin as grains of sand. Locked in an oyster, a granule grows into an iridescent pearl, lustrous and lovely to behold. While hurtling through the atmosphere at 35 kilometers per second, a generous cosmic sand grain becomes an awe-inspiring meteor, its transient beauty displayed for any who care to watch. This years Geminid meteor shower peaked last week with sky enthusiasts counting as many as 150 meteors per hour, despite the din of bright moon. Pictured above the Taftan volcano in southeast Iran, a meteor streaks between the bright star Sirius on the far left and the familiar constellation of Orion toward the image center. Sky watchers are looking forward to next years Geminids which should peak during an unobstructive new Moon.

APOD: 2011 November 22 - Leonid Fireball over Tenerife
Explanation: Historically active, this year's Leonid meteor shower was diminished by bright moonlight. Still, faithful night sky watchers did see the shower peak on November 18 and even the glare of moonlight didn't come close to masking this brilliant fireball meteor. The colorful meteor trail and final flare was captured early that morning in western skies over the Canary Island Observatorio del Teide on Tenerife. Particles of dust swept up when planet Earth passes near the orbit of periodic comet Tempel-Tuttle, Leonid meteors typically enter the atmosphere at nearly 70 kilometers per second. Looking away from the Moon, the wide angle camera lens also recorded bright stars in the familiar constellations Orion and Taurus near picture center. Inset are two exposures of this fireball's persistent train. The consecutive train images follow the meteor's flash by several minutes as high altitude winds disperse the faint, smokey trail. The two large telescope buildings are the GREGOR telescope with reddish dome and the Vacuum Tower Telescope along the right edge of the frame, both sun watching telescopes.

APOD: 2011 October 19 - Draconid Meteors Over Spain
Explanation: What are those streaks in the sky? They're meteors from the Draconids meteor shower that peaked earlier this month. The above composite image captured numerous meteor streaks over 90 minutes above the Celtic ruins of Capote in Badajoz province, Spain. The particles that caused these meteors were typically the size of a pebble and were expelled long ago from the nucleus of comet 21P/Giacobini-Zinner. Most of the above meteors can be traced back to a single radiant emanating from the constellation of the Dragon (Draco). Reports from this year's meteor shower indicate that the Draconids were unusually good this year with activity was concentrated around 8 pm UT on October 8. The most intense Draconid meteor showers in recent history occurred in 1933 and 1946 when thousands of meteors per hour were recorded as the Earth plowed through particularly dense streams of comet debris. Although the Draconids occur every October, it is usually difficult to know just how active each year's meteor shower will be.

APOD: 2011 October 2 - Tunguska: The Largest Recent Impact Event
Explanation: Yes, but can your meteor do this? The most powerful natural explosion in recent Earth history occurred on 1908 June 30 when a meteor exploded above the Tunguska River in Siberia, Russia. Detonating with an estimated power 1,000 times greater than the atomic bomb dropped over Hiroshima, the Tunguska event leveled trees over 40 kilometers away and shook the ground in a tremendous earthquake. Eyewitness reports are astounding. The above picture was taken by a Russian expedition to the Tunguska site almost 20 years after the event, finding trees littering the ground like toothpicks. Estimates of the meteor's size range from 60 meters to over 1000 meters in diameter. Recent evidence suggests that nearby Lake Cheko may even have been created by the impact. Although a meteor the size of the Tunguska can level a city, metropolitan areas take up such a small fraction of the Earth's surface that a direct impact on one is relatively unlikely. More likely is an impact in the water near a city that creates a dangerous tsunami. One focus of modern astronomy is to find Solar System objects capable of creating such devastation well before they impact the Earth.

APOD: 2011 August 17 - Perseid Below
Explanation: Denizens of planet Earth watched this year's Perseid meteor shower by looking up into the moonlit night sky. But this remarkable view captured by astronaut Ron Garan looks down on a Perseid meteor. From Garan's perspective onboard the International Space Station orbiting at an altitude of about 380 kilometers, the Perseid meteors streak below, swept up dust left from comet Swift-Tuttle heated to incandescence. The glowing comet dust grains are traveling at about 60 kilometers per second through the denser atmosphere around 100 kilometers above Earth's surface. In this case, the foreshortened meteor flash is right of frame center, below the curving limb of the Earth and a layer of greenish airglow. Out of the frame, the Sun is on the horizon beyond one of the station's solar panel arrays at the upper right. Seen above the meteor near the horizon is bright star Arcturus and a star field that includes the constellations Bootes and Corona Borealis. The image was recorded on August 13 while the space station orbited above an area of China approximately 400 kilometers to the northwest of Beijing.

APOD: 2011 August 13 - Castle and Meteor by Moonlight
Explanation: Each August, as planet Earth swings through dust trailing along the orbit of periodic comet Swift-Tuttle, skygazers enjoy the Perseid Meteor Shower. As Earth moves through the denser part of the comet's wide dust trail this year's shower peaks around 6:00 UT August 13 (this morning), when light from a nearly full Moon masks all but the brighter meteor streaks. Still, Perseid meteors can be spotted in the days surrounding the peak. Moonlight and a Perseid meteor created this gorgeous skyscape, recorded in a simple, single, 10 second long exposure on the morning of August 12. Below the moonlit clouds in the foreground are the ruins of a medieval castle near Veszprem, Hungary, seen against the Bakony mountain range. In the night sky above the clouds, the Perseid meteor's trail is joined by bright planet Jupiter near the center of the frame along with the lovely Pleiades star cluster at the left.

APOD: 2011 January 14 - Quadrantids over Qumis
Explanation: The Quadrantid Meteor Shower is an annual event for planet Earth's northern hemisphere skygazers. It usually peaks briefly in the cold, early morning hours of January 4. The shower is named for its radiant point on the sky within the old, astronomically obsolete constellation Quadrans Muralis. That position is situated near the boundaries of the modern constellations Hercules, Bootes, and Draco. In this haunting time exposure, two quadrantid meteor streaks are captured crossing trails left by rising stars of the constellations Virgo and Corvus, but Saturn leaves the brightest "star" trail. The meteor streaks, one bright and one faint, are nearly parallel above and right of center in the frame. Fittingly, the old cistern structure in the foreground lies above the now buried city of Qumis. Known as a city of many gates, Qumis (in Greek history Hecatompylos), was founded 2300 years ago in ancient Persia.

APOD: 2010 December 17 - A Meteor Moment
Explanation: Intensely bright, this fireball meteor flashed through Tuesday's cold, clear, early morning skies over the Karkas Mountains in central Iran, near the peak of the annual Geminid Meteor Shower. To capture the meteor moment and wintery night skyscape, the photographer's camera was fixed to a tripod, its shutter open for about 1.5 minutes. During that time, the multitude of stars slowly traced short, arcing trails through the sky, a reflection of planet Earth's daily rotation on its axis. The meteor's brilliant dash through the scene was brief, though. Changing color as it went, it also left a reddish swirl of hot, glowing gas near the center of its path. The mountains appear in silhouette against the steady glow of distant city lights.

APOD: 2010 December 16 - Geminids over Kitt Peak
Explanation: Two large telescope domes stand in the foreground of this night sky view from Kitt Peak National Observatory, near Tucson, Arizona, USA. The dramatic scene was recorded early Tuesday morning, near the peak of December's Geminid Meteor Shower. With dome slit open, the building closest to the camera houses the 2.3 Meter (90 inch) Bok Telescope operated by Steward Observatory, University of Arizona. Behind the Bok is the Mayall 4 Meter telescope dome. Of course, no telescopes were needed to enjoy the meteors streaking through the sky! The composite image consists of 13 exposures each 15 seconds long, taken with a wide angle lens over a period of about 2 hours during Kitt Peak's warm, clear, night. An annual celestial event, this meteor shower is the result of planet Earth plowing through dust from mysterious, asteroid-like object 3200 Phaethon.

APOD: 2010 December 12 - Leonids Above Torre de la Guaita
Explanation: In 1999, Leonids Meteor Shower came to an impressive crescendo. Observers in Europe saw a sharp peak in the number of meteors visible around 0210 UTC during the early morning hours of November 18. Meteor counts then exceeded 1000 per hour - the minimum needed to define a true meteor storm. At other times and from other locations around the world, observers typically reported respectable rates of between 30 and 100 meteors per hour. This photograph is a 20-minute exposure ending just before the main Leonids peak began. Visible are at least five Leonid meteors streaking high above the Torre de la Guaita, an observation tower used during the 12th century in Girona, Spain. Over the next few nights, the Geminids are expected to put on the best meteor show of this year.

APOD: 2010 December 11 - Meteor in the Desert Sky
Explanation: Created as planet Earth sweeps through dusty debris from mysterious, asteroid-like, 3200 Phaethon, the annual Geminid Meteor Shower should be the best meteor shower of the year. The Geminids are predicted to peak on the night of December 13/14, but you can start watching for Geminid meteors this weekend. The best viewing is after midnight in a dark, moonless sky, with the shower's radiant constellation Gemini well above the horizon - a situation that favors skygazers in the northern hemisphere. In this picture from the 2009 Geminid shower, a bright meteor with a greenish tinge flashes through the sky over the Mojave Desert near Barstow, California, USA. Recognizable in the background are bright stars in the northern asterism known as the Big Dipper, framing the meteor streak.

APOD: 2010 August 21 - Perseid Storm
Explanation: Storms on the distant horizon and comet dust raining through the heavens above are combined in this alluring nightscape. The scene was recorded in the early hours of August 13 from the Keota Star Party site on the Pawnee National Grasslands of northeastern Colorado, USA. Looking east across the prairie, the composite of 8 consecutive exposures each 30 seconds long captures the flash of lightning and a bright Perseid meteor. On the right, even the clouds can't block the light from brilliant planet Jupiter, whose mythological namesake knew how to handle both lightning bolts and meteors. Of course, this meteor's streak points back toward the shower's radiant in the heroic constellation Perseus, sharing a starry background that includes the Pleiades star cluster poised above the storm clouds. Just above the bright meteor lies the faint Andromeda Galaxy.

APOD: 2010 August 14 - Night of the Perseids
Explanation: On the night of August 12, from moonset until dawn was a good time to see meteors. Enthusiasts watched as comet dust rained on planet Earth, streaking through dark skies during the annual Perseid Meteor Shower. Anticipating the shower approaching its peak, astronomer Marco Verstraaten recorded a series of exposures capturing meteors over a period of 6 hours using a wide angle lens from a not-so-dark site in the Netherlands. Combining them still produced this dramatic night sky view with many colorful meteor streaks. The starry backdrop includes the Milky Way and even the faint Andromeda Galaxy, right of center. Although the comet dust particles are traveling parallel to each other, the shower meteors clearly seem to radiate from a spot on the sky in the eponymous constellation Perseus. The radiant effect is due to perspective, as the parallel tracks appear to converge at a distance. Bright stars in Perseus extend into the gap between the foreground trees.

APOD: 2010 July 22 - The Meteor of 1860
Explanation: Frederic Church (1826-1900), American landscape painter of the Hudson River School, painted what he saw in nature. And on July 20th, 1860, he saw a spectacular string of fireball meteors cross the Catskill evening sky, an extremely rare Earth-grazing meteor procession. From New York City, poet Walt Whitman (1819-1892) also wrote of the "... strange huge meteor procession, dazzling and clear, shooting over our heads" in his poem Year of Meteors (1859-60). But the inspiration for Whitman's words was forgotten. His astronomical reference became a mystery, the subject of scholarly debate until Texas State University physicists Donald Olson and Russell Doescher, English professor Marilynn Olson, and Honors Program student Ava Pope, located reports documenting the date and timing of the spectacular meteor procession. The breakthrough was spotting the connection with Church's relatively little-known painting. Fittingly, the forensic astronomy team's work was just published, on the 150th anniversary of the cosmic event that inspired both poet and painter.

APOD: 2010 June 2 - A Twisted Meteor Trail Over Tenerife
Explanation: Did this meteor take a twisting path? No one is sure. Considered opinions are solicited. Meteors, usually sand sized grains that originate in comets, will typically disintegrate as they enter the Earth's atmosphere. A fast moving meteor ionizes molecules in the Earth's atmosphere that subsequently glow when they reacquire electrons. Meteor paths that twist noticeably have been noted before, and even photographed, but attributing such behavior to the motion of the meteor itself and neither the wind-blown meteor train nor the observer remains somewhat controversial. The above meteor, imaged two weeks ago streaking over the Teide Observatory in Tenerife, Canary Islands, appears to swagger as much as several minutes of arc, which the experienced astrophotographer did not think could be attributed to drifting of the resulting train or motion of the camera mount. If truly an indication of a twisted meteor path, an underlying reason could be the pictured meteor was markedly non-spherical in shape, non-uniform in composition, or electrically charged. Non-uniform meteors, for example, may evaporate more on one side than another, causing a rotating meteor to wobble. Understanding meteors is important partly because meteors are candidates to have seeded Earth with prebiotic molecules that allowed for the development of life.

APOD: 2009 December 19 - Aurora Shimmer, Meteor Flash
Explanation: Northern Lights, or aurora borealis, haunted skies over the island of Kvaløya, near Tromsø Norway on December 13. This 30 second long exposure records their shimmering glow gently lighting the wintery coastal scene. A study in contrasts, it also captures the sudden flash of a fireball meteor from December's excellent Geminid meteor shower. Streaking past familiar stars in the handle of the Big Dipper, the trail points back toward the constellation Gemini, off the top of the view. Both aurora and meteors occur in Earth's upper atmosphere at altitudes of 100 kilometers or so, but aurora are caused by energetic charged particles from the magnetosphere, while meteors are trails of cosmic dust.

APOD: 2009 December 18 - Southern Geminids
Explanation: At least 34 meteors are included in this composite image as they rain through Australian skies during the annual Geminid Meteor shower. Dust particles strung out along the orbit of extinct comet Phaethon vaporize when they plow through planet Earth's atmosphere causing the impressive display. Although the particles are traveling parallel to each other, the resulting streaks clearly seem to radiate from a single point on the sky near Gemini's twin stars Castor and Pollux at the lower right. The radiant effect is due to perspective, as the parallel tracks appear to converge at a distance. Taken over a period of 2 hours on the morning of December 14, short exposures recording individual meteor streaks were combined with a single long exposure to show the background stars, with Sirius at the top, and the constellation Orion at left. Faint stars and nebulae of the Milky Way track through the center of the frame. Near the radiant point, an extra star in Gemini is actually the flash of a meteor seen almost head-on.

APOD: 2009 December 17 - Mojave Desert Fireball
Explanation: Monstrously bright, this fireball meteor lit up the Mojave Desert sky Monday morning, part of this year's impressive Geminid meteor shower. Seen toward the southwest over rock formations near Victorville, California, a more familiar celestial background was momentarily washed out by the meteor's flash. The background includes bright star Sirius at the left, and Aldebaran and the Pleaides star cluster at the right side of the image. The meteor itself blazes through the constellation Orion. Its greenish trail begins just left of a yellow-tinted Betelgeuse and points back to the shower's radiant in Gemini, just off the top of the frame. A rewarding catch for photographer Wally Pacholka, the spectacular image is one of over 1500 frames that he reports captured 48, mostly faint, Geminid meteors.

APOD: 2009 December 12 - Geminid Meteor over Monument Valley
Explanation: The Geminids are expected to put on a good show this year. Created as planet Earth sweeps through dusty debris from extinct comet Phaethon, the annual Geminid meteor shower is predicted to peak on December 14th, around 0510 UT (12:10am EST). With better viewing for northern hemisphere observers, pictures of Geminids streaking through the night could include wintery landscapes, like this snow-tinged image of a 2007 Geminid meteor over buttes of the Monument Valley region in the southwestern US. The meteor streak points back to the constellation Gemini and the shower's radiant point, just off the upper left edge of the scene. Along with Rigel, the sword and belt stars of Orion are at the upper right. Near the eastern horizon are bright stars Procyon (left) and Sirius. The two buttes at the far left are known as The Mittens - clearly a reminder that if you want to watch a meteor shower on a cold December night, wearing mittens would be a good idea.

APOD: 2009 November 20 - Meteor between the Clouds
Explanation: This bright meteor streaked through dark night skies over Sutherland, South Africa on November 15. Potentially part of the annual Leonid meteor shower, its sudden, brilliant appearance, likened to a camera's flash, was captured by chance as it passed between two clouds. Of course, the two clouds are also visible to the eye in dark southern skies - the Large and Small Magellanic Clouds - satellite galaxies of our own Milky Way. This year's Leonid meteor shower peaked on November 17 as the Earth passed through the stream of dust from periodic comet Tempel-Tuttle.

APOD: 2009 November 19 - Leonid over Mono Lake
Explanation: Eerie spires of rock rise from shore of Mono Lake in the foreground of this early morning skyscape. The salty, mineral-laden lake is located in California's eastern Sierra Nevada mountain range and the spindly rock formations are naturally formed limestone towers called tufa. In the scene, recorded near the peak of the annual Leonid meteor shower (now subsiding) on November 17th, a meteor trails through the frigid predawn sky. Arcturus is the brightest star to the right of the meteor streak, while the constellation Leo and the shower's radiant point lie well above the field of view. Reports for this year's Leonids suggest the peak activity briefly exceeded 120 meteors per hour, but rates were typically much lower for many locations.

APOD: 2009 October 15 - Fireball Meteor Over Groningen
Explanation: The brilliant fireball meteor captured in this snapshot was a startling visitor to Tuesday evening's twilight skies over the city of Groningen. In fact, sightings of the meteor, as bright as the Full Moon, were widely reported throughout the Netherlands and Germany at approximately 17:00 UT. Accompanied by sonic booms and rumbling sounds, the meteor was seen to break up into bright fragments, eventually leaving a persistent smoke-like trail. Even though there are bright fireball meteors in planet Earth's atmosphere every day, sightings of them are relatively rare because they more often occur over oceans and uninhabited areas.

APOD: 2009 August 15 - Meteor by Moonlight
Explanation: Dark skies are favored for viewing meteor showers. But the annual Perseid Meteor Shower still entertained skygazers around the world this week even though the Moon brightened the night. At its last quarter phase and rising around midnight on August 13, after the shower's anticipated peak, the Moon is seen here above rock formations in the Alborz Mountains near Firouzkooh, Iran. With a dramatic desert landscape in the foreground, a Perseid meteor is streaking through the moonlit sky between the overexposed Moon and bright planet Jupiter at the upper right. A regular celestial event in the northern hemisphere, the Perseid Meteor Shower is caused by planet Earth's yearly passage through the dust stream cast off by comet Swift-Tuttle.

APOD: 2009 August 14 - Shuttle and Meteor
Explanation: This early morning skyscape was captured last week on August 4th, looking northeast across calm waters in the Turn Basin at NASA's Kennedy Space Center. In a striking contrast in motion, the space shuttle Discovery, mounted on a massive transporter, creeps toward launch pad 39A at less than two miles per hour, while a brilliant meteor streaks through the sky traveling many miles per second. Of course, this week skywatchers have seen many similar meteor streaks during the annual Perseid meteor shower. But the meteor flashing above Discovery is not likely to be one of the Perseids because its path doesn't point back to that shower's radiant. Seen here near picture center, brilliant planet Venus still dominates the sky as the Morning Star, though. Yellowish tinted Mars lies near the top of the frame and Orion's red giant star Betelgeuse is toward the right.

APOD: 2009 August 11 - Inside Barringer Meteor Crater
Explanation: What happens when a meteor hits the ground? Usually nothing much, as most meteors are small, and indentations they make are soon eroded away. About 50,000 years ago, however, a large meteor created Barringer Meteor Crater in Arizona, USA. Also known simply as Meteor Crater, the resulting impact basin spans over a kilometer. Pictured above, a tour group views the inside of Barringer Crater early last year. Historically, Barringer Crater was the first feature on Earth to be recognized as an impact crater. Today, over 100 terrestrial impact features have been identified on planet Earth. Computer modeling indicates that some of the Canyon Diablo impactor melted during the impact that created Barringer.

APOD: 2009 May 11 - Forty Thousand Meteor Origins Across the Sky
Explanation: Where do meteors come from? Visible meteors are typically sand-sized grains of ice and rock that once fragmented from comets. Many a meteor shower has been associated with a known comet, although some intriguing orphan showers do remain. Recently, a group of meteor enthusiasts created a network of over 100 video cameras placed at 25 well-separated locations across Japan. This unprecedented network recorded not only 240,000 optically bright meteors over two years, but almost 40,000 meteors seen by more than one station. These multiple-station events were particularly interesting because they enabled the observers to extrapolate meteor trajectories back into the Solar System. The resulting radiant map is shown above, with many well known meteor showers labelled by the first three letters of the home constellation. Besides known meteor showers, eleven new showers were identified by new radiants on the sky from which meteors appear to flow. The meteor sky is ever changing, and it may be possible that new shower radiants will appear in the future. Research like this could also potentially identify previously unknown comets or asteroids that might one day pass close to the Earth.

APOD: 2009 May 1 - Lyrid Meteor and Milky Way
Explanation: On April 22nd, the Lyrid Meteor Shower visited planet Earth's sky, an annual shower produced as the Earth plows through dust from the tail of comet Thatcher. Usually Lyrid meteor watchers see only a drizzle. Just a few meteors per hour stream away from the shower's radiant point near bright star Vega in the constellation Lyra. But photographer Tony Rowell still managed to catch one bright Lyrid meteor. Recorded in early morning hours, his well-composed image looks toward the south from White Mountains of eastern California, USA. During the time exposure, he briefly illuminated an old mining cabin in the region's Ancient Bristlecone Pine Forest in the foreground. The rich starfields and dust clouds of our own Milky Way galaxy stretch across the background, along the meteor's glowing trail.

APOD: 2009 January 5 - Comet and Meteor
Explanation: This meteor streaking toward the horizon through the early morning sky of January 4th is from the annual Quadrantid meteor shower. Aligned with the shower's radiant point high in the north (off the top of the view), the meteor trail passes to the right of bright bluish star Beta Scorpii. Remarkably, near the top of the trail is a small spot, the fuzzy greenish glow of a comet. Discovered in July of 2007, Comet Lulin (C/2007 N3), is too faint now to be easily seen by the unaided eye, but will likely brighten to become visible to skygazers by late February. The well-timed skyscape featuring both comet and meteor is particularly appropriate as cometary bodies are known to be the origins of planet Earth's annual meteor showers.

APOD: 2008 September 11 - Mountain Top Meteors
Explanation: A mountain top above the clouds and light-polluted cities was a good place to go to watch this August's Perseid meteor shower. In fact, this composite picture from one of the highest points in Romania, the Omu summit (2,507 meters) in the Southern Carpathian Mountains, captures about 20 of the shower's bright streaks against a starry night sky. The cosmic debris stream that creates the shower is composed of dust particles moving along parallel paths, following the orbit of their parent comet Swift-Tuttle. Looking toward the shower's radiant point in the constellation Perseus, perspective causes the parallel meteor streaks to appear to diverge. But looking directly away from the radiant point, as in this view, perspective actually makes the Perseid meteors seem to be converging toward a point below the horizon.

APOD: 2008 August 16 - Perseid over Vancouver
Explanation: Colorful and bright, the city lights of Vancouver, Canada are reflected in the water in this portrait of the world at night. Recorded on August 12 during the Perseid Meteor Shower, the wide-angle view takes in a large swath along the photographer's eastern horizon. The picture is a composite of many consecutive 2 second exposures that, when added together, cover a total time of an hour and 33 minutes. During that time, stars trailed through the night sky above Vancouver, their steady motion along concentric arcs a reflection of planet Earth's rotation. The dotted trails of aircraft also cut across the scene. Of course, two of the frames captured the brief, brilliant flash of a Perseid fireball as it tracked across the top of the field of view. The large gap in the single meteor trail corresponds to the time gap between the consecutive frames.

APOD: 2008 August 14 - Perseid Trail
Explanation: This bright and colorful meteor flashed through Tuesday's early morning skies, part of the annual Perseid Meteor Shower. The lovely image is one of over 350 frames captured on August 12 from the Joshua Tree National Park, in California, USA . Dust from comet Swift-Tuttle is responsible for the Perseids, creating the northern hemisphere's regular summer sky show. The comet dust is vaporized as it enters the atmosphere at upwards of 60 kilometers per second, producing visible trails that begin at altitudes of around 100 kilometers. Of course, the trails point back to a radiant point in the constellation Perseus, giving the meteor shower its name. Recorded after moonset, the starry background features the bright star Vega on the right. Extending below the western horizon is the faint band of the northern Milky Way.

APOD: 2008 August 9 - Aurora Persei
Explanation: Dark skies are favored for viewing meteor showers -- so the best viewing of this year's Perseids will occur in the early morning. While the Perseid meteor shower is scheduled to peak over the next few days, bright light from a gibbous Moon will also flood the early evening and mask the majority of relatively faint meteors. Still, skygazing in the early morning after the Moon sets (after about 2 AM local time) could reveal many faint meteors. Persistant observing at any time after sunset can reward northern hemisphere watchers looking for occasional Perseid fireballs. Astronomer Jimmy Westlake imaged this bright Perseid meteor despite the combination of moonlight and auroral glow over Colorado skies in August of 2000.

APOD: 2008 January 7 - Quadrantid Meteors and Aurora from the Air
Explanation: Where do meteor showers originate? To help answer this question, astronomers studied in some detail the Quadrantid meteor shower that occurred over this past weekend. In particular, astronomers with specialized cameras flew as part of the Quadrantid's Multi-Instrument Aircraft Campaign (MAC) aboard a Gulfstream V aircraft above northern Canada over the past few days and studied the Quadrantid meteor shower in unprecedented detail. Pictured above is a composite image combining many short exposures. Visible in the image are the wingtip of the airplane reflecting a red beacon on the left, green aurora most prominent on the image right, and numerous meteor streaks throughout. Preliminary indications are that the meteor stream is quite stable in time but variable in meteor abundance. Over 100 meteors per hour were visible at the peak from the MAC aircraft. Meteor data from around the world will continue to be analyzed to try to verify Peter Jenniskens's recent hypothesis that minor planet 2003 EH1 is an intermittently active comet and the parent body of the annual Quadrantid meteor shower.

APOD: 2008 January 3 - Geminids in 2007
Explanation: Dust from curious near-Earth asteroid 3200 Phaethon seems to fall from the constellation Gemini in this fisheye skyview. The composite image was recorded over four December nights (12-15) just last year from Ludanyhalaszi, Hungary. Of course, the streaks are meteor trails from the annual Geminids meteor shower. The work of astronomer Erno Berko, the finished picture combines 113 different frames and captures 123 separate meteors. The Geminids is one of the northern skies most reliably performing meteor showers and did not disappoint last year. Under good conditions some skywatchers reported well over 100 meteors per hour near the December 14/15 peak for the Geminids in 2007. Look up tonight and you might see the 2008 Quadrantids.

APOD: 2007 November 14 - Tunguska: The Largest Recent Impact Event
Explanation: Yes, but can your meteor do this? The most powerful natural explosion in recent Earth history occurred on 1908 June 30 when a meteor exploded above the Tunguska River in Siberia, Russia. Detonating with an estimated power 1,000 times greater than the atomic bomb dropped over Hiroshima, the Tunguska event leveled trees over 40 kilometers away and shook the ground in a tremendous earthquake. Eyewitness reports are astounding. The above picture was taken by a Russian expedition to the Tunguska site almost 20 years after the event, finding trees littering the ground like toothpicks. Estimates of the meteor's size range from 60 meters to over 1000 meters in diameter. Recent evidence suggests that nearby Lake Cheko may even have been created by the impact. Although a meteor the size of the Tunguska can level a city, metropolitan areas take up such a small fraction of the Earth's surface that a direct impact on one is relatively unlikely. More likely is an impact in the water near a city that creates a dangerous tsunami. One focus of modern astronomy is to find Solar System objects capable of creating such devastation well before they impact the Earth.

APOD: 2007 October 9 - Aurora, Stars, Meteor, Lake, Alaska
Explanation: Sometimes, after your eyes adapt to the dark, a spectacular sky appears. In this case, a picturesque lake lies in front of you, beautiful green aurora flap high above you, brilliant stars shine far in the distance, and, for a brief moment, a bright meteor streaks by. This digitally fused breathtaking panorama was captured late last month across one of the Chena Lakes in North Pole, Alaska, USA, and includes the Pleiades open cluster of stars on the image right. The shot is unusual not only for the many wonders it has captured simultaneously, but because lakes this far north tend to freeze and become non-reflecting before a sky this dark can be photographed.

APOD: 2007 August 16 - Moonless Perseid Sky
Explanation: Last weekend, dark, moonless night skies brought many sightings of Perseid meteors to skygazers all over planet Earth. Early Sunday morning astronomer John Chumack's camera captured this Perseid meteor streak with a flare near the end of its track over Yellow Springs, Ohio. The single, four minute long exposure looks toward the constellation of Taurus and the eastern horizon. The meteor streak points back to the annual meteor shower's radiant in Perseus off the upper left corner of the picture. Of course, the view includes the well-known Pleiades Star cluster (near top center) with a bright yellowish planet Mars below it. Also seen with a yellowish tint but not quite as bright as Mars, the giant star Aldebaran anchors the V-shaped Hyades star cluster left of center, above the trees.

APOD: 2006 November 21 - A Leonid Meteor Over Sweden
Explanation: This past weekend, small remnant bits of a distant comet lit up the skies over much of planet Earth. Incoming reports, however, have this year's Leonid meteor shower as less active than Leonid meteor showers a few years ago. Nevertheless, some sky enthusiasts reported peak meteor bursts as high as one visual meteor per minute. The parent body of the Leonids meteor shower, Comet Tempel-Tuttle, leaves a trail of expelled sand-size particles every 33 years when it returns to the inner Solar System. When the Earth passes through a stream of these Sun-orbiting particles, a meteor shower results. Pictured above, a Leonid meteor was captured two days ago during the early morning hours of November 19 over Vallentuna, Sweden. Although activity levels in meteor showers are notoriously hard to predict, some astronomers speculate that Aurigids meteor shower next September might be unusually rich in bright meteors.

APOD: 2006 October 23 - Orionid Meteors Over Turkey
Explanation: Meteors have been flowing out from the constellation Orion. This was expected, as mid-October is the time of year for the Orionids Meteor Shower. Pictured above, over a dozen meteors were caught in successively added exposures over three hours taken this past weekend from a town near Bursa, Turkey. The above image shows brilliant multiple meteor streaks that can all be connected to a single point in the sky just above the belt of Orion, called the radiant. 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 might show an even more impressive shower from some locations.

APOD: 2006 August 19 - Ceci n'est pas un Meteore
Explanation: To paraphrase Magritte, "This is not a meteor". It's not a picture of a meteor either, but it was taken during last weekend's peak of the Perseid Meteor shower. Skywatching with friends at a cosy beach campsite bathed in moonlight at Treguennec, France, astronomer and APOD translator Laurent Laveder planned to record bright Perseid meteors with camera and tripod. While the Perseid meteors he saw were neither numerous nor bright he did capture the brilliant trail of an Iridium communication satellite. His long exposure began after the satellite glint became visible, so the resulting streak does resemble a meteor trail in the final image. Also recognizable in the serene view of sandy beach and starry sky is the famous northern asterism, the Big Dipper.

APOD: 2006 August 17 - Comet Dust over Colorado
Explanation: The rock formation in the foreground of this night view was recorded on August 10, illuminated by light from a waning gibbous Moon. Even though the sky above also scatters the bright moonlight, a brilliant meteor was captured as it flashed across the scene during the 30 second long exposure. Of course, the meteor was part of the annual rain of dust from periodic Comet Swift-Tuttle known as the Perseid Meteor Shower. Leaving trails that point back to a radiant in the constellation Perseus, the ancient dust particles are vaporized as they enter the atmosphere at about 60 kilometers per second, their visible streaks beginning at altitudes of around 100 kilometers. And though it looks like the knuckles of a giant hand, the curious rock formation can be found in Colorado National Monument park, USA, planet Earth.

APOD: 2006 August 11 - Perseid in the Light
Explanation: Dark skies are favored for viewing meteor showers -- so many are pessimistic about this year's Perseids. While the Perseid meteor shower is scheduled to peak this weekend, bright light from an almost full Moon will also flood the night and mask the majority of relatively faint meteors. Still, skygazing in the evening before the Moon rises (before about 10 PM local time) could reveal spectacular earthgrazing meteors. Persisting even later into the moonlit night can reward northern hemisphere watchers looking for occasional Perseid fireballs. In fact, astronomer Jimmy Westlake imaged this bright Perseid meteor despite the combination of moonlight and auroral glow over Colorado skies in August of 2000.

APOD: 2005 November 15 - A Taurid Meteor Fireball
Explanation: Have you ever seen a very bright meteor? Unexpected, this year's Taurid meteor shower resulted in numerous reports of very bright fireballs during the nights surrounding Halloween. Pictured above, a fireball that momentarily rivaled the brightness of the full Moon was caught over Cerro Pachon, Chile by a continuous sky monitor on November 1. Several bright Taurid fireballs are identifiable on the sky movie for that night. The above image is a digitally rectangled version of a circular fisheye frame and shows the entire sky, horizon to horizon. The bright meteor was seen swooping between the directions of the Large and Small Magellanic Clouds. The band of the Milky Way Galaxy crosses the horizon behind the dome of the 8-meter Gemini South Telescope. Taurid meteor fireballs are likely pebble sized debris left by Comet Encke. Over the next week the Leonids meteor shower will peak, although they will need to be seen through the glare of a nearly full Moon. [Disclosure: Robert Nemiroff collaborates on both the Astronomy Picture of the Day and the Night Sky Live projects.]

APOD: 2005 August 15 - Perseid Meteors and the Milky Way
Explanation: Where will the next Perseid meteor appear? Sky enthusiasts who trekked outside for the Perseid meteor shower that peaked over the past few days typically had this question on their mind. The above movie, where the time-line has been digitally altered, captures part of that very mystery. Eight meteors from the night of August 12 and the morning of August 13 have been identified in the movie so far, seven of which are Perseids. Can you identify the non-Perseid meteor? Since all Perseid meteors appear to come from the constellation of Perseus, the non-Perseid meteor is the one that streaks in a different direction. Early reports are that this year's Perseids were unfortunately a bit disappointing. The above digital mosaic was taken from Alsace, France, with the photogenic band of our Milky Way Galaxy far in the background.

APOD: 2005 August 12 - A Meteor Shower Fireball Movie
Explanation: Go outside tonight and see a celestial light show -- the later the better. Tonight is the peak of the month-long Perseid Meteor Shower. Although visible every year at this time, the Perseids are expected to appear particularly active this year due to the relative absence of glare from the Moon during the peak. Tonight, a thin moon will set a few hours after the Sun, leaving a moonless and dark sky. All through the night, all over the sky, meteors will appear to shoot out the constellation Perseus and across the sky. The rate of meteors and fireballs is not known for sure, but expected by some to be as high as one meteor flash every minute. Lucky sky gazers might be treated to a bright fireball like the one pictured above. That fireball was captured by a digital recorded over Wise Observatory during the 2001 Leonid Meteor Shower. The meteor shower poses no danger as few, if any, of the sand-sized flaring bits are expected to reach the ground.

APOD: 2005 August 6 - Raining Perseids
Explanation: Comet dust rained down on planet Earth last August, streaking through dark skies in the annual Perseid meteor shower. So, while enjoying the anticipated space weather, astronomer Fred Bruenjes recorded a series of many 30 second long exposures spanning about six hours on the night of August 11/12 using a wide angle lens. Combining those frames which captured meteor flashes, he produced this dramatic view of the Perseids of summer. Although the comet dust particles are traveling parallel to each other, the resulting shower meteors clearly seem to radiate from a single point on the sky in the eponymous constellation Perseus. The radiant effect is due to perspective, as the parallel tracks appear to converge at a distance. Bruenjes notes that there are 51 Perseid meteors in the composite image, including one seen nearly head-on. This year, the Perseids Meteor Shower will peak in the early morning hours on Friday, August 12.

APOD: 2005 February 2 - A Twisted Meteor Train
Explanation: Did this meteor leave a twisting path? Evidently. Meteor trains that twist noticeably are rare - and even more rarely photographed - but have been noted before. The underlying reason for unusual meteor trains is that many meteors are markedly non-spherical in shape and non-uniform in composition. Meteors, usually sand sized grains that originate in comets, will disintegrate as they enter the Earth's atmosphere. Non-uniform meteors may evaporate more on one side than another. This may cause a rotating meteor to wobble slightly in its path, and also to spray fast moving debris in a nearly spiral path. The fast moving meteor debris ionizes molecules in the Earth's atmosphere that subsequently glow when they reacquire electrons. Surely no meteor is perfectly uniform and spherical, so that a slight swagger that is below perceptibility is likely typical. Meteors may well have seeded Earth with the prebiotic molecules that allowed for the development of life.

APOD: 2004 December 22 - Comet, Meteor, Nebula, Star
Explanation: Several wonders of the late-year northern sky appeared together for a few fleeting moments on December 13. On the bottom left, just above the hill, is blue Sirius, the brightest star in the sky. Above Sirius and slightly to the right of the belt of Orion is the red Orion Nebula, one of the most famous nebulas on the sky. Below and to the right of the Orion Nebula streaks a yellow meteor, although moving in the wrong direction to be from the Geminids meteor shower that peaked the night. Finally, above and to the right of the meteor is Comet Machholz, whose coma appears here relatively green. Since the time since this image was taken over a Californian hill, the Geminid meteor has long since evaporated. Comet Machholz has brightened and moved to the north. Sirius, however, will remain in the constellation of Canis Major indefinitely.

APOD: 2004 November 23 - Leonid Meteors Streak
Explanation: The 2004 Leonids meteor shower had its ups and downs. Although average rates were significantly less than many previous years, as expected, at least two unexpected "mini-outbursts" of several bright meteors over a few minutes were reported. Pictured above, a bright Leonid meteor was imaged by a Night Sky Live camera over Kitt Peak National Observatory early in the morning of November 19 during one mini-outburst. The meteor appears as the streak just to the left of the green "Ursa Major" label. Moving your cursor over the image will show the image taken about 25 minutes later where two bright Leonid meteors from a second mini-outburst were recorded, visible on the lower right just to the left of the green words "Canis" and "Minor". The stars appear to shift between the two images because of the rotation of the Earth. The Night Sky Live frames show fisheye images, capturing the entire sky as a person would see it looking straight up, including peripheral vision. In mid-December, the Geminids meteor shower will give sky enthusiasts another good chance to see live meteors.

APOD: 2004 November 14 - Leonids Above Torre de la Guaita
Explanation: The 1999 Leonids Meteor Shower came to an impressive crescendo. Observers in Europe observed a sharp peak in the number of meteors visible around 0210 UTC during the early morning hours of November 18. Meteor counts then exceeded 1000 per hour - the minimum needed to define a true meteor storm. At other times and from other locations around the world, observers typically reported respectable rates of between 30 and 100 meteors per hour. The above photograph is a 20-minute exposure ending just before the main Leonids peak began. Visible are at least five Leonids meteors streaking high above the Torre de la Guaita, an observation tower used during the 12th century in Girona, Spain. This year's Leonids should peak twice on November 19th, but is predicted to be less impressive than in 1999.

APOD: 2004 August 20 - Raining Perseids
Explanation: Comet dust rained down on planet Earth last week, streaking through dark skies in the annual Perseid meteor shower. So, while enjoying the anticipated space weather, astronomer Fred Bruenjes recorded a series of many 30 second long exposures spanning about six hours on the night of August 11/12 using a wide angle lens. Combining those frames which captured meteor flashes, he produced this dramatic view of the Perseids of summer. Although the comet dust particles are traveling parallel to each other, the resulting shower meteors clearly seem to radiate from a single point on the sky in the eponymous constellation Perseus. The radiant effect is due to perspective, as the parallel tracks appear to converge at a distance. Bruenjes notes that there are 51 Perseid meteors in the composite image, including one seen nearly head-on.

APOD: 2004 August 13 - Perseid Fireball Over Japan
Explanation: Enjoying the bright Moon's absence from early morning skies, observers around the world reported lovely displays during this year's Perseid meteor shower. As anticipated, peak rates were about one meteor per minute. Though most Perseids were faint, this bright and colorful fireball meteor flashed through skies over Japan on August 12 at 0317 JST. Ending at the upper right, the meteor's trail points down and to the left, back to the shower's radiant point between the constellations of Perseus and Cassiopeia, seen here just above the tower structure in the foreground. The Pleiades star cluster is also visible well below the meteor's trail. Perseid shower meteors can be traced to particles of dust from the tail of comet Swift-Tuttle. The comet dust impacts the atmosphere at speeds of around 60 kilometers per second. While this annual shower's peak has come and gone, Perseid meteors should still be visible over the next few nights, but at a greatly reduced rate.

APOD: 2004 August 12 -The Spectrum of A Meteor
Explanation: Chasing the brief flash of a meteor trail across the sky with a very large telescope is a nearly impossible task. But on May 12, 2002, astronomers got lucky, as a bright meteor chanced across the narrow slit of their spectrograph at the Paranal Observatory. At the time, the spectrograph was being used to study the light from a supernova, separating and recording the many near-infrared emission lines produced by atoms in the distant stellar explosion. Below this artistic montage of a meteor streak and Very Large Telescope units at Paranal, panel a shows the near-infrared sky background spectrum and the May 12 meteor combined. Panel b shows the emission spectrum of the meteor alone, after subtracting away the background contributions. The meteor emission is due to colliding oxygen and nitrogen atoms and molecules in the superheated air along the glowing trail at an altitude of about 100 kilometers.

APOD: 2004 August 11 - A Perseid Meteor
Explanation: The ongoing Perseid Meteor Shower should be at its strongest tonight and tomorrow night. Although meteors should be visible all night long, the best time to watch will be between 2:00 AM and dawn each night. In dark, moonless, predawn skies you may see dozens of meteors per hour. Sky enthusiasts in Europe and Asia might see an unusual burst of meteors near 2100 hours UT. Grains of cosmic sand and gravel shed from Comet Swift-Tuttle will streak across the sky as they vaporize during entry into Earth's atmosphere. Tracing the meteor trails backwards, experienced skygazers will find they converge on the constellation Perseus, thus this annual meteor shower's name. Pictured above is a Perseid meteor from 2002 over a rock formation in the US Southwest desert. Shadowing and blurring are caused by the long 10-minute exposure. The brightest Perseids can be seen from anywhere on Earth by monitoring the continuously returning images from the Night Sky Live cameras.

APOD: 2003 November 25 - A Late Leonid from a Sparse Shower
Explanation: The 2003 Leonids Meteor Shower contained relatively few meteors. As expected and unlike the last few years, the Earth just did not pass through any dense particle streams left over by the Sun-orbiting Comet Tempel-Tuttle. Preliminary reports had the peak meteor rates only as high as about one relatively faint meteor a minute even from good locations at good times. Pictured above is one of the brighter Leonids of 2003, caught by one of the continuously operating night sky web cameras (CONCAMs) of the global Night Sky Live project. The fisheye image shows the night sky from horizon to horizon above Mauna Kea, Hawaii, USA. The image is annotated with several bright stars and planets. Note that this meteor, as do all Leonids, appears to emanate from the constellation Leo, labeled on the upper left. Although the peak of the Leonids this year was on November 19, this meteor flashed through the sky the next night.

APOD: 2003 November 18 - Leonids Over Indian Cove
Explanation: One year ago today an impressive meteor shower graced the skies of Earth. Pictured above from last year, at least six bright meteors are visible in only part of the sky above Indian Cove campground in California, USA, during a four-minute exposure. The 2002 Leonids packed a double punch with planet Earth plunging through two dense clouds of meteroids, dusty debris left by the passage of Comet Tempel-Tuttle. This year, unfortunately, the main peak of the Leonids Meteor Shower is not expected to be so impressive, with the Earth passing though parts of meteoroid clouds predicted to be much less dense. The main peak of the 2003 Leonids is predicted for tomorrow where some locations might see a bright meteor every minute.

APOD: 2003 November 16 - Leonids from Leo
Explanation: Is Leo leaking? Leo, the famous sky constellation visible on the left of the above all-sky photograph, appears to be the source of all the meteors seen in 1998's Leonids Meteor Shower. That Leonids point back to Leo is not a surprise - it is the reason that this November meteor shower is called the Leonids. Sand-sized debris expelled from Comet Tempel-Tuttle follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation Leo. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Leo. Over 150 meteors can be seen in the above four-hour effort. The Leonids Meteor Shower of 2003 is expected to have two peaks, the first three days ago and the second a long-duration peak covering much of November 19. Although visible meteor rates might approach one per minute, they are predicted to be much less than in the previous few years.

APOD: 2003 August 9 - A Perseid Aurora
Explanation: Just after the Moon set but before the Sun rose in the early morning hours of 2000 August 12, meteors pelted the Earth from the direction of the constellation Perseus, while ions pelted the Earth from the Sun. The meteors were expected as sub-sand grains long left behind by Comet Swift-Tuttle annually create the Perseids Meteor Shower. The aurorae were unexpected, however, as electrons, protons, and heavier ions raced out from a large Coronal Mass Ejection that had occurred just days before on the Sun. In the foreground is Hahn's Peak, an extinct volcano in Colorado, USA. The Perseid meteor shower peaks this year over the next few days, with as much as one bright meteor per minute visible from some locations.

APOD: 2002 November 17 - Leonids from Leo
Explanation: Is Leo leaking? Leo, the famous sky constellation visible on the left of the above all-sky photograph, appears to be the source of all the meteors seen in last year's Leonids Meteor Shower. That Leonids point back to Leo is not a surprise - it is the reason that this November meteor shower is called the Leonids. Sand-sized debris expelled from Comet Tempel-Tuttle follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation Leo. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Leo. Over 100 bright meteors can be seen in the above half-hour exposure. The intensity of the Leonid Meteor Shower in 2002 is uncertain but may approach one per second for some locations on November 18 and 19.

APOD: 2002 August 23 - Island Universe, Cosmic Sand
Explanation: On August 13, while counting Perseid meteors under dark, early morning Arizona skies, Rick Scott set out to photograph their fleeting but fiery trails. The equipment he used included a telephoto lens and fast color film. After 21 pictures he'd caught only two meteors, but luckily this was one of them. Tracking the sky, his ten minute long exposure shows a field of many stars in our own Milky Way galaxy, most too faint to be seen by the unaided eye. Flashing from lower left to upper right, the bright meteor would have been an easy eyeful though, as friction with Earth's atmosphere vaporized the hurtling grain of cosmic sand, a piece of dust from Comet Swift-Tuttle. Just above and left of center, well beyond the stars of the Milky Way, lies the island universe known as M31 or the Andromeda galaxy. The visible meteor trail begins about 100 kilometers above Earth's surface, one of the closest celestial objects seen in the sky. In contrast, Andromeda, about 2 million light-years away, is the most distant object easily visible to the naked-eye.

APOD: 2002 August 15 - Meteors and Northern Lights
Explanation: Skygazers report that the annual Perseid meteor shower went pretty much as predicted, producing a meteor every few minutes during the dark early morning hours of August 12 and 13. And as the constellation Perseus rose above the horizon on the night of August 11, astrophotographer Wade Clark was anticipating recording images of the flashing meteor trails from the Mt. Baker Ski Area in northwest Washington, USA. But Clark was also treated to a colorful display of northern lights. As a result, the stars of Perseus are arrayed near the center of his well composed skyscape along with trails of Perseid meteors all viewed through the auroral glow. The alluring scene might look familiar to watchers of bygone Perseids. For many, views of the meteor shower in 2000 also coincided with auroral displays, courtesy of the active Sun.

APOD: 2002 August 11 - A Perseid Meteor
Explanation: The ongoing Perseid Meteor Shower should be at its strongest on August 12 and 13. The best time to watch will be between 2:00 AM and dawn on Monday morning (so plan on setting your alarm tonight!) and then again on Tuesday. In dark, moonless, predawn skies you may see dozens of meteors per hour. Grains of cosmic sand and gravel shed from Comet Swift-Tuttle will streak across the sky as they vaporize during entry into Earth's atmosphere. Tracing the meteor trails backwards, experienced skygazers will find they converge on the constellation Perseus, thus this annual meteor shower's name. Pictured above is a Perseid meteor from 1993. The colors are representative but digitally enhanced. As the meteor streaked across the night sky, different excited atoms emitted different colors of light. The origin of the green tinge visible at the right is currently unknown, however, and might result from oxygen in Earth's atmosphere.

APOD: 2001 November 30 - Meteor Storm Sights and Sounds
Explanation: This dramatic four-frame animation shows a fireball meteor and its developing persistent "smoke" train, recorded two weeks ago in skies near Salvador, Brazil. Indeed similar sights are astonishingly familiar world-wide to witnesses of this November's fireball-rich Leonid meteor storm. A few skygazers even discovered that some bright Leonid fireballs made faint, gentle, hissing sounds(!), a surprising effect only recently appreciated and understood. Accounts of fireball meteors making noise have long been viewed with skepticism, particularly because sounds were reportedly heard just as the meteor was seen overhead. But light travels much faster than sound so, like delayed thunder from a distant lightning stroke, a meteor produced sound should only be heard long after the meteor streak was seen. A sound explanation supported by laboratory tests is that turbulent plasma created by the meteor's passage generates very low frequency radio waves. Traveling at light speed the radio waves reach the ground simultaneously with visible light where they are strong enough to induce oscillating currents and audible vibrations in common objects like grass, leaves, wire-frame glasses, and perhaps even dry, frizzy hair.

APOD: 2001 November 22 - Fireball, Smoke Trail, Meteor Storm
Explanation: Returning from orbit, space shuttles enter the atmosphere at about 8 kilometers per second as friction heats their protective ceramic tiles to over 1,400 degrees Celsius. By contrast, the bits of comet dust which became the Leonid meteors seen on November 18, were moving at 70 kilometers per second, completely vaporizing at altitudes of around 100 kilometers. In this single 5 minute time exposure, three Leonid meteors are shooting through skies above Spruce Knob, West Virginia, USA. Background stars are near the constellation Orion. The brightest meteor, a fireball, dramatically changes colors along its path and leaves a smokey persistant trail drifting in high-altitude winds. From that extremely dark site, at an elevation of 1,200 meters, astrophotographer Jerry Lodriguss reports, "We observed a [zenithal hourly rate] of about 3,600 at 10:30 UT and very high rates from 9:30 UT until well into the start of astronomical twilight at 10:50 UT. It was quite a spectacular storm, with bolides going off like flashbulbs, green and red fireballs and other fainter Leonids in all parts of the sky."

APOD: 2001 November 20 - A Leonids Star Field
Explanation: As meteor after meteor streaked across a moonless sky, photographers across the world snapped pictures of the 2001 Leonids Meteor Shower. Many recognized this as the best meteor shower they had ever seen. In fact, the 2001 Leonids was the most active meteor shower since the mid-1960s. The above photo captures three Leonid meteors crossing a photogenic star-field. On the far right is the Pleiades star cluster. The brightest meteor crosses right in front of the Hyades star cluster, situated below the image center. Just left of center is the bright planet Saturn, and the bright star below Saturn is Aldebaran. The ten-minute exposure was taken near Victoria, British Columbia, Canada at 2:45 am PST on 2001 November 18.

APOD: 2001 November 19 - A 2001 Leonids Meteor Shower Fireball
Explanation: The 2001 Leonids Meteor Shower gave quite a show to many parts of the world yesterday during the early morning hours. Many sleepy observers venturing into their own backyards were treated to several bright meteors per minute streaking across the sky. This rate made the 2001 Leonids the most active meteor shower in over three decades. Pictured above is a bright Leonid fireball that briefly lit up Hawaii yesterday morning. A CONCAM nighttime all-sky monitor on Mauna Kea, a dormant volcano, caught the bright meteor, seen as the very bright streak across the lower part of the fisheye image. The meteor track crossed the Galactic plane (the faint glow that runs from the lower left to upper right), passed below the planet Jupiter, and through the constellation Orion. CONCAMs in Hawaii, Arizona, and California all recorded numerous bright meteors during this year's Leonids.

APOD: 2001 November 18 - A Leonid Meteor Explodes
Explanation: Last night and tonight, a lucky few may see a meteor explode. As our Earth passes unusually close to debris expelled from Comet Tempel-Tuttle, many sand-sized particles from this comet are entering and burning up in the Earth's atmosphere. This yearly phenomenon is known as the Leonids Meteor Shower, but the location the Earth passes through this year holds promise to provide relatively high activity. In particular, the 1998 Leonids was noteworthy for its many bright meteors. In the above slow-loading sequence, a 1998 Leonid was caught exploding over Los Alamos, New Mexico. In the last one-minute exposure, another Leonid streaks past.

APOD: 2001 November 11 - An Annotated Leonid
Explanation: The 1998 Leonids Meteor Shower was one of the most photographed meteor events in history. Patient observers saw bright meteors streak across dark skies every few minutes, frequently leaving fading trails stretching across the sky. High above the Anza-Borrego Desert, a meteor was photographed streaking up from the radiant constellation of the Leonids: Leo. This meteor train covered over 40 degrees, and changed colors from green to red. The intensity of the Leonid Meteor Shower in 2001 is uncertain but may approach one per second for some locations on November 18.

APOD: 2001 August 10 - Perseids of Summer
Explanation: Like falling stardust, cast off bits of comet Swift-Tuttle hurtle through the upper atmosphere about this time each year as planet Earth passes near the comet's orbital path. For the northern hemisphere, this regular celestial display is known as the annual Perseid meteor shower -- so named because the meteor trails all appear traceable to a common "radiant point" in the constellation Perseus. This gorgeous wide-angle photo from the 1997 shower captures a 20-degree-long fireball meteor and another, fainter Perseid meteor trail in a rich area of the northern summer Milky Way. A labeled version is available identifying the shower's radiant point, surrounding deep-sky objects, and constellations. Easy to view (just go outside and look up!), the Perseid meteor shower will peak this weekend with maximum rates anticipated early Sunday morning, August 12, for eastern North America. Despite interfering moonlight, last year's faithful Perseid watchers were rewarded with bright meteors and extensive displays of the northern lights.

APOD: 2000 November 29 - Leonids from Orbit
Explanation: Here is what a meteor shower looks like from orbit. During the peak of the 1997 Leonid Meteor Shower, the MSX satellite imaged from above 29 meteors over a 48 minute period entering the Earth's atmosphere. From above, meteors create short bright streaks. Visible beneath the meteors are clouds lit by reflected moonlight, while visible above is the constellation of Aries. The directions of the meteor streaks are nearly parallel, confirming that the meteors all originate from the same meteor stream. Recent analysis of the 2000 Leonids meteor shower indicates to many astronomers that the 2001 Leonids may develop into a real meteor storm, with meteor rates perhaps exceeding one per second visible from parts of Asia.

APOD: 2000 November 24 - Long Leonid
Explanation: Just last week this long lovely Leonid shower meteor arced through the night. Captured on November 17/18 by photographer Bob Yen, the meteor trail spans about 70 times the apparent diameter of the full moon in the skies above Mt. Wilson, California, USA. The Leonid's path flashes from the outskirts of constellation Gemini to the triangle-shaped head of Taurus (lower right). Of course, the trail points back toward Leo, the shower's eponymous radiant, while passing near such night sky notables as galactic star cluster M35 (upper left) and Taurus's brightest star, red giant Aldebaran. Though the sky was ruled by a bright but waning Moon and brilliant Jupiter, the Leonid meteor shower still awed observers at dark sky locations with peak rates of hundreds of meteors per hour.

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 November 17 - Leonid Sunrise
Explanation: Such beautiful things begin as grains of sand. Locked in an oyster a granule grows into an iridescent pearl, lustrous and lovely to behold. While hurtling through the atmosphere at 70 kilometers per second, a cosmic sand grain becomes an awe-inspiring meteor, its transient beauty displayed for any who care to watch. Framed perfectly between orange clouds at sunrise, this bright meteor trail was photographed from the Joshua Tree National Park in California, USA during the 1998 Leonid Meteor Shower. Appropriately titled "Leonid Sunrise", the picture was recorded on high-speed film (ASA 3200) with a 35mm camera. Its striking colors and grainy, textured appearance suggest a painting on canvas. Of course, you could see Leonid meteors at sunrise for yourself. With clear skies, your next chance is coming up ... tomorrow morning.

APOD: 2000 September 4 - Aurora Persei
Explanation: Last month, skywatchers were treated to an unexpected coincidence: bright aurorae occurred during the Perseid Meteor Shower. The above picture was taken August 12 and captures eerie looking aurorae and a faint Perseid meteor above Cross Lake in Wisconsin, USA. The near future holds promise for both more aurorae and a better meteor shower. Aurorae are becoming increasingly common as their trigger -- our Sun -- nears its period of highest activity during its eleven-year magnetic cycle. Coming up in mid-November is the quirky Leonids Meteor Shower. Although one of the better studied meteor showers, the Leonids have surprised astronomers many times and so many an optimistic skywatcher promises to be outside this year hoping for a memorable show.

APOD: 2000 August 12 - A Perseid Meteor
Explanation: This weekend, the annual Perseid Meteor Shower reaches its maximum. Grains of cosmic sand and gravel shed from Comet Swift-Tuttle will streak across the sky as they vaporize during entry into Earth's atmosphere. The Perseids result from the yearly crossing of the Earth through Comet Swift-Tuttle's orbit. The Perseids are typically the most active meteor shower of the year. In a clear dark sky, an observer might see a meteor a minute near peak times, but this year a bright moon will overwhelm the glow from many perseid meteors until moonset in the early morning hours. Pictured above is a Perseid meteor from 1993. The colors are representative but digitally enhanced. As the meteor streaked across the night sky, different excited atoms emitted different colors of light. The origin of the green tinge visible at the right is currently unknown, however, and might result from oxygen in Earth's atmosphere. Perseid meteors can best be seen from a relaxing position, away from lights, just before the dawn twilight.

APOD: 2000 April 28 - Leonid Glowworm
Explanation: Recent Leonid meteor showers have been rich in bright fireball meteors which leave lingering trails stretching across the night sky. These trails, or persistent trains, are mysteriously self-luminescent and do not shine by reflected light. Visible for many minutes, they are blown by winds at altitudes up to 100 kilometers and can take on progressively twisted worm-like shapes. Recorded in November, during the 1998 Leonid meteor shower, this picture shows a persistent train dubbed "Glowworm" by astronomers at Kirtland Air Force Base's Starfire Optical Range (SOR). What makes the Glowworm glow? To find out, SOR astronomers engaged in a unique experiment, tracking and probing both 1998 and 1999 Leonid meteor trains with pulsed laser lidar (light detection and ranging) systems and other instruments. A copper vapor laser produced the intense streak seen shooting from the lower left of the image. While the cause of the Glowworm's glow remains enigmatic for now, the SOR results will help unravel the mystery.

APOD: November 24, 1999 - A Leonids Meteor Storm in 1999
Explanation: The 1999 Leonids meteor shower was not equally good for everybody. Only observers in Europe and the Middle East with clear skies near 2 am (UTC) on 1999 November 18 saw rates shoot up to a meteor every few seconds. Above, however, is a picture taken from Spain during this time, with over a dozen faint meteors visible as green streaks eminating from Leo during just a six minute exposure. Although more numerous, the 1999 Leonids did not have the same high proportion of bright meteors and fireballs as the 1998 Leonids. Last year's Leonid fireballs have been traced back to the 1333 passage of Comet Tempel-Tuttle. The orbit of Jupiter continually deflected one stream of cast-off particles while the smallest meteors in this stream were removed by light pressure from the Sun. The remaining Leonids were relatively large, pea sized or larger, compared to the sand-sized Leonids that are more common.

APOD: November 18, 1999 - A Sirius Leonid Meteor
Explanation: In the sky or on the web, did you watch this year's Leonid meteor shower? If you did, meteors flashing through the night sky should be a familiar sight. Recorded last year during the 1998 apparition of the Leonids, this time-exposure of the sky around the constellation Canis Major (big dog) shows the trail of a spectacular fireball meteor. The meteor, by chance, seems to leap from the constellation's brightest star Sirius, near the top right. In the foreground is the beautiful desert scenery of Joshua Tree National Park. At this year's peak of the cosmic dust storm, observers in Europe and Africa reported intense rates of over 1600 meteors per hour for a brief period near 0215 November 18 (UTC). Awe inspiring as they were, the Leonids posed no danger to earthbound skywatchers.

APOD: November 17, 1999 - A Leonid Meteor Explodes
Explanation: Tonight, a lucky few may see a meteor explode. Over the next 36 hours the Earth will pass unusually close to debris expelled from Comet Tempel-Tuttle, causing many sand-sized particles from this comet to enter and burn up in the Earth's atmosphere. This yearly phenomenon is known as the Leonids Meteor Shower, but the location the Earth passes through this year holds promise to provide particularly high activity. The 1998 Leonids was noteworthy for its many bright meteors. In the above slow-loading sequence, a 1998 Leonid was caught exploding over Los Alamos, New Mexico. In the last one-minute exposure, another Leonid streaks past. If tonight is clear, just grab a lawn chair and a warm jacket, go outside, and look up!

APOD: November 13, 1999 - Tempel Tuttle: The Leonid Comet
Explanation: Star trails streak this composite time exposure of Comet Tempel-Tuttle recorded by T. Puckett on January 26, 1998. Then passing through the inner solar system on its 33 year orbit around the Sun, Tempel-Tuttle brightened unexpectedly, but binoculars or small telescopes were still required to visually observe it. Tempel-Tuttle is also called "the Leonid Comet" as the yearly Leonid meteor shower results when the Earth crosses this comet's orbital plane and encounters cometary dust. So, while not rivaling spectacular naked-eye comets like Hyakutake or Hale-Bopp, Tempel-Tuttle still puts on a show. When the Earth plunges through Tempel-Tuttle's debris tail in November of this year, many sky-watchers are anticipating an extremely active meteor shower to result, perhaps even a meteor storm!

APOD: November 12, 1999 - 1998 Leonid Fireball
Explanation: Will this be the year? Last year's Leonid meteor shower did not produce the meteor storm many had hoped for. Still, it put on a dazzling show with many bright fireball meteors. For example, this Leonid fireball, photographed through light clouds, eerily flashed across the skies of Monteromano, Italy on November 17, 1998. This year, the chances for a storm with thousands of meteors per hour are considered good ... but experts are quick to acknowledge that such predictions are tricky. Want to see for yourself? The predicted peak should occur on early Thursday, November 18 (UTC) but meteor activity will certainly be observable days before and after. If the night is clear, just grab a lawn chair and a warm jacket, go outside and look up!

APOD: October 22, 1999 - Iridium 52: Not A Meteor
Explanation: While hunting for meteors in the night sky above the White Mountains near Bishop, California, astrophotographer James Young instead captured this brilliant celestial apparition. Recorded near twilight on August 13, the bright streak is not the flash of a meteor trail but sunlight glinting from a satellite. The satellite, Iridium 52, is one of a constellation of Iridium digital communication satellites in Earth orbit known for producing stunning, predictable "flares" as they momentarily reflect sunlight from shiny antenna surfaces. For well placed observers, the peak brightness of this Iridium satellite flare reached about -6 magnitude, not quite as bright as the half illuminated moon. At magnitude 2.5, the bright star at the left is Alpha Pegasi, a star in the constellation Pegasus.

APOD: August 11, 1999 - A Meteor Over the Anza Borrego Desert
Explanation: Meteors will be flashing across your skies over the next two nights. Specifically, the Perseid Meteor Shower should be at its best just before each morning's dawn. Observers at dark locations might see as much as a meteor a minute. Perseid meteors are bits of dirt that blew off Comet Swift-Tuttle and that burn up as they fall to Earth. Exciting expectations of a new filament in the Perseids might be tested this year. Pictured above is a meteor from the most active meteor shower of last year: the Leonids. Pictured above, a Leonid meteor was caught in November outshining even the brightest stars over the Anza-Borrego Desert in California. The Leonids will peak again this November and might provide an ever better show.

APOD: December 29, 1998 - A Geminid from Gemini
Explanation: The Leonid meteor shower was not the only good meteor shower this season. Earlier this month, the annual Geminids meteor shower peaked, featuring as many as 140 meteors per hour from some locations. Geminid meteors can be seen streaking away from the constellation of Gemini, as depicted in the above all-sky photograph. The origin of the Geminid meteors is somewhat uncertain but thought to be small bits broken off the unusual asteroid 3200 Phaetheon. Many observers reported that the 1998 Geminids were typically less bright than the 1998 Leonids, but appeared more bunched, with groups of two or three meteors sometimes appearing simultaneously. Next years' Geminids might be better yet.

APOD: December 22, 1998 - Dawn of the Leonids
Explanation: Many of the 1998 Leonid shower meteors were so bright they could be seen even during sunrise. The above photograph was taken near the dawn of November 16 close to Hong Kong, China. However, most meteors are fainter and are not associated with any particular meteor shower. On any given night from a dark location it would not be unusual to see up to 10 meteors per hour, while the predictable Meteor showers might feature 100 meteors per hour. A true meteor storm will occur only a few times per century. The actual intensity of meteor storms is notoriously hard to predict, but may feature rates upwards of 10 meteors per second.

APOD: November 30, 1998 - An Annotated Leonid
Explanation: The 1998 Leonids Meteor Shower was perhaps the most photographed meteor event in history. Patient observers saw bright meteors streak across dark skies every few minutes, frequently leaving fading trails stretching across the sky. High above the Anza-Borrego Desert, a meteor was photographed streaking up from the radiant constellation of the Leonids: Leo. This meteor train covered over 40 degrees, and changed colors from green to red.

APOD: November 27, 1998 - Twisting Meteor Train
Explanation: Blazing through the sky at 70 kilometers per second, 100 kilometers or so above planet Earth, many bright Leonid meteors left behind a persistent, smoke-like trail of glowing, hot, ionized gas. Twisting in high altitude winds, these trails or trains typically were visible for many minutes. As Iowa astrophotographer Tom Bailey captured the eerie, wispy remains of this persistent train from a fireball arcing overhead, yet another fainter Leonid meteor flashed across the sky.

APOD: November 26, 1998 - Meteor Milky Way
Explanation: The bold, bright star patterns of Orion (right) are a familiar sight to even casual skygazers. But this gorgeous color photo also features a subtler spectacle - the faint stars of the Milky Way. A broad region of the Milky Way runs vertically through the picture with the striking red Rosette Nebula in bloom left of center. Cutting across this dim, diffuse band of stars which lie along the plane of our Galaxy is a meteor streak. It seems to pass just under the red-orange giant star Betelgeuse at Orion's shoulder. Astrophotographer Jeff Medkeff recorded this and other beautiful time exposures from a dark sky countryside southeast of Sierra Vista, Arizona USA, during November's Leonid meteor shower.

APOD: November 23, 1998 - A Leonid Meteor Explodes
Explanation: Click on the above image and watch a Leonid meteor explode. The tremendous heat generated by the collision of a small sand-bit moving at 70 kilometers/second with the Earth's upper atmosphere causes the rock-fragment to heat up, glow brightly, and disintegrate. In some cases, the meteor literally explodes leaving a visible cloud that dissipates slowly. The above image shows just such an explosion for a bright meteor from the recent Leonid Meteor Shower. Clicking on the above image will start a (4.2 Megabtye) movie of thirty 1-minute exposures showing the explosion cloud dissipate. Each movie frame, taken with the ROTSE telescope early 17 November, is 8 degrees across - 16 times the diameter of the full moon. Near the middle of the sequence, a less bright meteor moves through the field.

APOD: November 19, 1998 - Bright Leonids
Explanation: Rich in bright and awesome fireballs, the Leonid Meteor Shower came early this year. In fact, judging from meteor watcher reports the peak came nearly 15 hours earlier than the best predictions. Observers on the Canary Islands were probably close to an ideal viewing location and recorded a maximum of effectively about 200 to 250 meteors per hour near dawn on November 17 - way below the peak rate during the 1966 Leonid meteor storm display. Still, those blessed with clear skies in dark, early morning hours all over planet Earth were treated to a first rate cosmic light show. Roving astrophotographer Olivier Staiger took this stunning image of two bright Leonids in the skies over Chiang Mai, Thailand.

APOD: November 16, 1998 - Leonids 1998: A Safe Meteor Storm
Explanation: You're in no danger. During the meteor storm occurring tonight and tomorrow, thousands of bits of ice and rock will likely rain onto the Earth. Few, if any, will hit the ground. Touted as potentially the most active meteor shower since 1966, the Leonids of 1998 will be tracked by observers the world over. The meteor storm is caused by the Earth moving through the leftover debris of Comet Temple-Tuttle. The peak of the storm will be best visible tomorrow from Asia, though increased activity should be visible globally over many hours. It is even possible to monitor the storm live on the web. Pictured above is a Perseid 1997 meteor streaking across the sky behind an illuminated California desert.

APOD: November 13, 1998 - A Leonid Fireball From 1966
Explanation: This bright fireball meteor was photographed from Table Mountain Observatory during the peak of the annual Leonid meteor shower on November 17, 1966. That was a good year for Leonid meteor watchers - a meteor "storm" was produced as the Earth swept through a dense swarm of dusty debris from the tail of comet Tempel-Tuttle. Observer Jim Young reported a peak rate for the 1966 shower of about 50 meteors per second and recorded 22 otherwise extremely rare, bright fireballs like this one in the span of 90 minutes from his California mountain top location. Predictions are uncertain, but this year might also produce an intense apparition of the Leonids shower which should again peak on the 17th. You may need to be well placed and a little lucky to see the shower at its maximum, but Leonid meteors should be easy to see in dark skies - particularly in early morning hours - for two or so days before and after the peak. How do you watch a meteor shower? Get a comfortable lawn chair and a warm jacket ... go outside and look up!

APOD: November 8, 1998 - Leonid Meteor Shower Next Week
Explanation: Early next week, a spectacular meteor storm is expected: the 1998 Leonids. It is widely thought that that the meteors from the Leonids meteor shower are just small pieces of Comet Temple-Tuttle falling to Earth. During each pass near the Sun, a comet will heat up and shed pieces of ice and rock from its nucleus. This debris continues to orbit the Sun until either evaporating or being swept up by some large solar-system body. A piece of comet debris striking the Moon creates a small crater, but a piece striking the Earth usually burns up in the atmosphere causing a brief, bright streak. The streak below center in the above picture of the northern sky actually depicts a meteor from the Perseid meteor shower, a usually impressive display that peaks every year in mid-August.

APOD: January 30, 1998 - Tempel-Tuttle: The Leonid Comet
Explanation: Star trails streak this composite time exposure of Comet Tempel-Tuttle recorded by T. Puckett on January 26. Presently passing through the inner solar system on its 33 year orbit around the Sun, Tempel-Tuttle has brightened unexpectedly, but binoculars or small telescopes are still required to visually observe it. Tempel-Tuttle is also called "the Leonid Comet" as the yearly Leonid meteor shower results when the Earth crosses this comet's orbital plane and encounters cometary dust. So, while not currently rivaling the spectacle of a Hyakutake or Hale-Bopp, Tempel-Tuttle may still put on a show. When the Earth plunges through Tempel-Tuttle's debris tail in November of this year, many sky-watchers are anticipating an extremely active meteor shower to result, perhaps even a meteor storm!

APOD: November 17, 1997 - Barringer Crater on Earth
Explanation: What happens when a meteor hits the ground? Usually nothing much, as most meteors are small, and indentations they make are soon eroded away. 49,000 years ago, however, a large meteor created Barringer Meteor Crater in Arizona, pictured above. Barringer is over a kilometer across. In 1920, it was the first feature on Earth to be recognized as an impact crater. Today, over 100 terrestrial impact craters have been identified. Early this morning, the Leonid Meteor Shower reaches its peak, although no impacts of this magnitude are expected.

APOD: November 16, 1997 - The Leonid Meteor Shower
Explanation: The Leonid Meteor Shower will likely reach its peak in the early hours this Monday morning. Though the Moon will be bright, Leo, the shower's radiant point, will be well above the eastern horizon from Western North America and the Pacific region during this period. This year's Leonids may prove particularly exciting as observers anticipate the legendary Leonid storm of activity will occur sometime during the next few apparitions of this annual meteor shower - although most expect the meteor storm to occur in 1998 or 1999. Meteor showers result from debris left by passing comets. The Leonids specifically are small pieces of Comet Tempel-Tuttle. In the above series of time-lapse, 1-minute exposures, a 1995 Leonid is seen to leave a train of hot air that glowed persistently for several minutes.

APOD: August 20, 1997 - Bright Meteor, Dark Sky
Explanation: Has Orion the Hunter acquired a new weapon? If you turn your head sideways (counterclockwise) you might notice the familiar constellation of Orion, particularly the three consecutive bright stars that make up Orion's belt. But in addition to the stars that compose his sword, Orion appears to have added some sort of futuristic light-saber, possibly in an attempt to finally track down Taurus the Bull. Actually, the bright streak is a meteor from the Perseid Meteor Shower, a shower that put on an impressive display last Tuesday morning, when this photograph was taken. This meteor was likely a small icy pebble shed years ago from Comet Swift-Tuttle that evaporated as it entered Earth's atmosphere.

APOD: August 11, 1997 - A Perseid Meteor
Explanation: Tonight the Perseid Meteor Shower reaches its maximum. Grains of rocky ice will streak across the sky as they evaporate during entry into Earth's atmosphere. These ice chips were shed from Comet Swift-Tuttle. The Perseids result from the annual crossing of the Earth through Comet Swift-Tuttle's orbit. The Perseids are typically the most active meteor shower of the year. In a clear dark sky, an observer might see a meteor a minute. Pictured above is a Perseid meteor from 1993. The colors are representative but digitally enhanced. As the meteor streaked across the night sky, different excited atoms emitted different colors of light. The origin of the green tinge visible at the right is currently unknown, however, and might result from oxygen in Earth's atmosphere. Perseid meteors can best be seen from a relaxing position, away from lights.

APOD: November 16, 1996 - The Leonid Meteor Shower (Tonight)
Explanation: Tonight thousands of icy rocks will hurl toward Earth in a fascinating display of light called the Leonid Meteor Shower. There is little danger - few will reach the ground. But this year's Leonids could be nothing compared to the Leonids in 1998. Then, the Leonids might rival any meteor storm this century, with peak rates possibly toping 40 per second. Meteor showers result from debris left by passing comets. The Leonids specifically are small pieces of Comet Tempel-Tuttle. In the above series of time-lapse, 1-minute exposures, a 1995 Leonid is seen to leave a train of hot air that glowed persistently for several minutes.

APOD: October 21, 1996 - Orionids Meteor Shower to Peak Tonight
Explanation: Tonight you might be able to see Halley's Comet again - or at least some pieces of it. It is widely thought that that the meteors from the Orionids meteor shower, which peaks tonight, are just small pieces of Halley's Comet falling to Earth. During each pass near the Sun, a comet will heat up and shed pieces of ice and rock from its nucleus. This debris continues to orbit the Sun until either evaporating or being swept up by some large solar-system body. A piece of comet debris striking the Moon creates a small crater, but a piece striking the Earth usually burns up in the atmosphere causing a brief, bright streak. Every year at this time the Earth crosses an old stream of bits from Halley's Comet causing the Orionids display, named from the constellation (Orion) from which the meteors appear to originate. The streak below center in the above picture of the northern sky actually depicts a meteor from the Perseid meteor shower, a usually even more impressive display that peaks every year in mid-August.

APOD: August 9, 1996 - The Perseid Meteor Shower
Explanation: From a radiant point in the constellation of Perseus, Comet Swift-Tuttle presents -- The Perseid Meteor Shower -- coming to your night sky this weekend! A bookish E. C. Herrick of New Haven, Connecticut correctly suspected in 1837 that this meteor shower was an annual event. Indeed it is now known to be a regular August shower caused by the yearly passage of the Earth through the orbiting debri left behind by periodic comet Swift-Tuttle. Since the bits of comet debri are moving along parallel orbits, on entering the atmosphere they leave fiery trails which appear to originate from a common radiant point in the sky, in this case in the constellation of Perseus. Dramatically illustrated in this composite video image made using MOVIE, meteors from the 1994 Perseids streak across the sky framed by the three bright stars of the asterism known as the "Summer Triangle". The image shows bright Perseids recorded that year from August 9 through 14. Here the trails appear nearly parallel as the camera was centered on the sky about 90 degrees from the radiant point. This year, European and North American observers should be able to view the shower near its maximum, about 90 meteors per hour, early Monday morning August 12, but the shower should be enjoyable on clear weekend nights (August 10,11) as well. After midnight is generally the best time for viewing. What's the best way to enjoy a meteor shower? Get a warm jacket and a comfortable lawnchair ... go outside and look up.

APOD: January 26, 1996 - Quadrantids: Meteors in Perspective
Explanation: Meteor showers are caused by streams of solid particles, dust size and larger, moving as a group through space. In many cases, the orbits of these meteor streams can be identified with the dust tails of comets. When the Earth passes through the streams, the particles leave brilliant trails through the night sky as they burn up in the atmosphere. Above is an image of a meteor shower known as the Quadrantids. It was made in January 1995 using MOVIE, a new system for making video meteor observations. To make the image, frames from a video tape were computer processed and superposed to show the relative paths of many meteors in the shower. The meteor paths are all parallel to each other, but the effect of perspective causes the trails to appear to originate from a distant radiant point in the sky. In contrast to the elongated meteor trails, the brighter stars of the familiar constellation Ursa Major (the Big Dipper) are visible as points in the lower half of the image.