omnianasa/nasa-apod-metadata huggingface dataset:
Apollo 17 Site: A Sharper View (2011-09-08)
This view of the Apollo 17 landing site in the Taurus-Littrow valley was captured last month by the Lunar Reconnaissance Orbiter (LRO), the sharpest ever recorded from space. The high resolution image data was taken during a period when LRO's orbit was modified to create a close approach of about 22 kilometers as it passed over some of the Apollo landing sites. That altitude corresponds to only about twice the height of a commercial airline flight over planet Earth. Labeled in this image are Apollo 17 lunar lander Challenger's descent stage (inset), the lunar rover (LRV) at its final parking spot, and the Apollo Lunar Surface Experiments Package (ALSEP) left to monitor the Moon's environment and interior. Clear, dual lunar rover tracks and the foot trails left by astronauts Eugene Cernan and Harrison Schmitt, the last to walk on the lunar surface, are also easily visible at the Apollo 17 site.
Comet Garradd and the Coat Hanger (2011-09-09)
Sweeping through planet Earth's night sky, last weekend Comet Garradd (C/2009 P1) visited this lovely star field along the Milky Way in the constellation Vulpecula. Suggestively oriented, the colorful skyscape features stars in the asterism known as the Coat Hanger with the comet's tail pointing toward the southeast. Also known as Al Sufi's Cluster, the Coat Hanger itself is likely just a chance alignment and not a cluster of related stars. But compact open star cluster NGC 6802 does grace the field of view just right of the Coat Hanger, near the edge of the frame. Below naked eye visibility but approaching 7th magnitude in brightness, Comet Garradd has been a good target for binoculars and small telescopes. Still, bright moonlit skies this week will make the comet harder to spot.
Rollback from GRAIL's Rocket (2011-09-10)
This dramatic time-lapse photo traces a 20 minute long, late evening rollback of the lighted Mobile Service Tower at Cape Canaveral Air Force Station Launch Complex 17. Twin spacecraft are snug inside the 13 story tall Delta 2 rocket poised for launch. The duo will journey to the Moon on NASA's Gravity Recovery and Interior Laboratory mission, GRAIL, using precision formation flying to map the Moon's gravity field. The scene was captured prior to the first launch attempt, canceled due to upper level winds, on September 8. Further launch opportunities for GRAIL begin this morning, September 10.  The GRAIL launch is the last one planned from Complex 17 on Cape Canaveral's oldest still active pad, in use since 1957.
On the Origin of Gold (2011-09-11)
Where did the gold in your jewelry originate?  No one is completely sure.  The relative average abundance in our Solar System appears higher than can be made in the early universe, in stars, and even in typical supernova explosions.  Some astronomers have recently suggested that neutron-rich heavy elements such as gold might be most easily made in rare neutron-rich explosions such as the collision of neutron stars.  Pictured above is an artist's illustration depicting two neutron stars spiraling in toward each other, just before they collide.  Since neutron star collisions are also suggested as the origin of short duration gamma-ray bursts, it is possible that you already own a souvenir from one of the most powerful explosions in the universe.
Tisdale 2 Rock Formation on Mars (2011-09-12)
Why does this Martian rock have so much zinc? Roughly the size and shape of a tilted coffee-table, this oddly flat, light-topped rock outcropping was chanced upon a few weeks ago by the robotic Opportunity rover currently rolling across Mars. Early last month Opportunity reached Endeavour crater, the largest surface feature it has ever encountered, and is now exploring Endeavour's rim for clues about how wet Mars was billions of years ago. Pictured above and named Tisdale 2, the unusual rock structure was probed by Opportunity last week and is now thought to be a remnant thrown off during the impact that created nearby Odyssey crater. The resulting chemical analysis of Tisdale 2, however, has shown it to have a strangely high amount of the element zinc. The reason for this is currently unknown, but might turn out to be a clue to the history of the entire region. Opportunity is already finding rocks older than any previously studied and will continue to explore several other intriguing rock formations only now glimpsed from a distance.
Great Orion Nebulae (2011-09-13)
The Great Nebula in Orion, also known as M42, is one of the most famous nebulas in the sky. The star forming region's glowing gas clouds and hot young stars are on the right in this sharp and colorful image that includes the smaller nebula M43 near center and dusty, bluish reflection nebulae NGC 1977 and friends on the left. Located at the edge of an otherwise invisible giant molecular cloud complex, these eye-catching nebulae represent only a small fraction of this galactic neighborhood's wealth of interstellar material. Within the well-studied stellar nursery, astronomers have also identified what appear to be numerous infant planetary systems. The gorgeous skyscape spans nearly two degrees or about 45 light-years at the Orion Nebula's estimated distance of 1,500 light-years.
The Bubble and M52 (2011-09-14)
To the eye, this cosmic composition nicely balances the Bubble Nebula at the lower right with open star cluster M52. The pair would be lopsided on other scales, though. Embedded in a complex of interstellar dust and gas and blown by the winds from a single, massive O-type star, the Bubble Nebula, also known as NGC 7635, is a mere 10 light-years wide.  On the other hand, M52 is a rich open cluster of around a thousand stars. The cluster is about 25 light-years across. Seen toward the northern boundary of Cassiopeia, distance estimates for the Bubble Nebula and associated cloud complex are around 11,000 light-years, while star cluster M52 lies nearly 5,000 light-years away. The wide telescopic field of view spans about 1.5 degrees on the sky or three times the apparent size of the Full Moon.
NGC 3521: Galaxy in a Bubble (2011-09-15)
Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years away, toward the constellation Leo. Relatively bright in planet Earth's sky, NGC 3521 is easily visible in small telescopes but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like M66 and M65. It's hard to overlook in this colorful cosmic portrait, though. Spanning some 50,000 light-years the galaxy sports characteristic patchy, irregular spiral arms laced with dust, pink star forming regions, and clusters of young, blue stars. Remarkably, this deep image also finds NGC 3521 embedded in gigantic bubble-like shells. The shells are likely tidal debris, streams of stars torn from satellite galaxies that have undergone mergers with NGC 3521 in the distant past.
September's Harvest Moon (2011-09-16)
A Full Moon rising can be a dramatic celestial sight, and Full Moons can have many names. For example, Monday's Full Moon was the one nearest this year's autumnal equinox for the northern hemisphere, traditionally called the Harvest Moon. According to lore the name is a fitting one because farmers could work late into the night at the end of the growing season harvesting crops by moonlight. This serene telephoto image captures this September's harvest moonrise from Turin, Italy. In silhouette against an orange lunar disk is Turin's hilltop Basilica of Superga.   APOD Retrospective: Harvest and Hunter Moons
Spitzer's Orion (2011-09-17)
Few cosmic vistas excite the imagination like the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This stunning false-color view spans about 40 light-years across the region, constructed using infrared data from the Spitzer Space Telescope. Compared to its visual wavelength appearance, the brightest portion of the nebula is likewise centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But the infrared image also detects the nebula's many protostars, still in the process of formation, seen here in red hues. In fact, red spots along the dark dusty filament to the left of the bright cluster include the protostar cataloged as HOPS 68, recently found to have crystals of the silicate mineral olivine within its protostellar envelope.
A Sharp View of the Sun (2011-09-18)
Here is one of the sharper views of the Sun ever taken. This stunning image shows remarkable details of a dark sunspot across the image bottom and numerous boiling granules which appear like kernels of corn across the top.  Taken in 2002, the picture was made using the Swedish Solar Telescope operating on the Canary Island of La Palma. The high resolution image was achieved using sophisticated adaptive optics, digital image stacking, and other processing techniques to counter the blurring effect of Earth's atmosphere. Currently a sunspot group is crossing the Sun that is so large it can be easily seen by the cautious observer even without magnification.
The South Pole of Asteroid Vesta (2011-09-19)
What created the circular structure around the south pole of asteroid Vesta? Pictured above, the bottom of the second largest object in the asteroid belt was recently imaged for the first time by the robotic Dawn satellite that arrived last month. A close inspection of the 260-meter resolution image shows not only hills and craters and cliffs and more craters, but ragged circular features that cover most of the lower right of the 500-kilometer sized object. Early speculation posits that the structure might have been created by a collision and coalescence with a smaller asteroid. Alternatively, the features might have originated in an internal process soon after the asteroid formed. New clues might come in the next few months as Dawn spirals down toward the rocky world and obtains images of increasingly high resolution.
Pleiades Deep Field (2011-09-21)
Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it like this: all dusty. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city.  With a long exposure from a dark location, though, the dust cloud surrounding the Pleiades star cluster becomes very evident. The above exposure took about 30 hours and covers a sky area several times the size of the full moon.  Also known as the Seven Sisters and M45, the Pleiades lies about 400 light years away toward the constellation of the Bull (Taurus).  A common legend with a modern twist is that one of the brighter stars faded since the cluster was named, leaving only six stars visible to the unaided eye. The actual number of Pleiades stars visible, however, may be more or less than seven, depending on the darkness of the surrounding sky and the clarity of the observer's eyesight.   APOD Retrospective: The Pleiades Star Cluster
Arp 272 (2011-09-22)
Linking spiral arms, two large colliding galaxies are featured in this remarkable cosmic portrait constructed using image data from the Hubble Legacy Archive. Recorded in astronomer Halton Arp's Atlas of Peculiar Galaxies as Arp 272, the pair is otherwise known as NGC 6050 near center, and IC 1179 at upper right. A third galaxy, likely also a member of the interacting system, can be spotted above and left of larger spiral NGC 6050. They lie some 450 million light-years away in the Hercules Galaxy Cluster. At that estimated distance, the picture spans over 150 thousand light-years. Although this scenario does look peculiar, galaxy collisions and their eventual mergers are now understood to be common, with Arp 272 representing a stage in this inevitable process. In fact, the nearby large spiral Andromeda Galaxy is known to be approaching our own galaxy and Arp 272 may offer a glimpse of the far future collision between Andromeda and the Milky Way.
September's Aurora (2011-09-23)
September's equinox arrives today at 0905 UT. As the Sun crosses the celestial equator heading south, spring begins in the southern hemisphere and autumn in the north. And though the seasonal connection is still puzzling, both spring and autumn bring an increase in geomagnetic storms. So as northern nights grow longer, the equinox also heralds the arrival of a good season for viewing aurora. Recorded earlier this month, these curtains of September's shimmering green light sprawl across a gorgeous night skyscape. In the foreground lies Hidden Lake Territorial Park near Yellowknife, Northwest Territories, Canada. Calm water reflects the aurora, with bright star trails peering through the mesmerizing sky glow. Of course, shining at altitudes of 100 kilometers or so, planet Earth's auroras are visible from space.
Mangaia's Milky Way (2011-09-24)
From Sagittarius to Carina, the Milky Way Galaxy shines in this dark night sky above planet Earth's lush island paradise of Mangaia. Familiar to denizens of the southern hemisphere, the gorgeous skyscape includes the bulging galactic center at the upper left and bright stars Alpha and Beta Centauri just right of center. About 10 kilometers wide, volcanic Mangaia is the southernmost of the Cook Islands. Geologists estimate that at 18 million years old it is the oldest island in the Pacific Ocean. Of course, the Milky Way is somewhat older, with the galaxy's oldest stars estimated to be over 13 billion years old. (Editor's note: This image holds the distinction of being selected as winner in the Royal Observatory, Greenwich, Astronomy Photographer of the Year competition in the Earth and Space category.)
A Large Tsunami Shock Wave on the Sun (2011-09-25)
Tsunamis this large don't happen on Earth.  During 2006, a large solar flare from an Earth-sized sunspot produced a tsunami-type shock wave that was spectacular even for the Sun.  Pictured above, the tsunami wave was captured moving out from active region AR 10930 by the Optical Solar Patrol Network (OSPAN) telescope in New Mexico, USA.  The resulting shock wave, known technically as a Moreton wave, compressed and heated up gasses including hydrogen in the photosphere of the Sun, causing a momentarily brighter glow.  The above image was taken in a very specific red color emitted exclusively by hydrogen gas.  The rampaging tsunami took out some active filaments on the Sun, although many re-established themselves later.  The solar tsunami spread at nearly one million kilometers per hour, and circled the entire Sun in a matter of minutes.
Dry Ice Pits on Mars (2011-09-26)
Part of Mars is defrosting. Around the South Pole of Mars, toward the end of every Martian summer, the warm weather causes a section of the vast carbon-dioxide ice cap to evaporate.  Pits begin to appear and expand where the carbon dioxide dry ice sublimates directly into gas. These ice sheet pits may appear to be lined with gold, but the precise composition of the dust that highlights the pit walls actually remains unknown.  The circular depressions toward the image center measure about 60 meters across. The HiRISE camera aboard the Mars-orbiting Mars Reconnaissance Orbiter captured the above image in late July.  In the next few months, as Mars continues its journey around the Sun, colder seasons will prevail, and the thin air will turn chilly enough not only to stop the defrosting but once again freeze out more layers of solid carbon dioxide.
Violent Sunspot Group AR 1302 Unleashes a Flare (2011-09-28)
One of the most active sunspot groups in years is currently crossing the Sun. AR 1302 first came around the Sun's edge last week and is so large it can be seen without a telescope.  Coronal Mass Ejections from AR 1302 have already caused strong geomagnetic storms including notable aurora activity around both of Earth's poles. Pictured above, plasma was left magnetically hanging above the Sun's surface after AR 1302 emitted an X-class solar flare last Thursday.  Earth is illustrated in the inset for a size comparison. Although another X-class flare was emitted on Saturday, no flares from AR 1302 have been aimed directly at the Earth, as yet. The AR 1302 sunspot group will continue to evolve but likely remain visible on the Sun for the next week.   Instant Gallery: See recent pictures of sunspot group AR 1302.
Cocoon Nebula Wide Field (2011-09-29)
In this crowded starfield spanning some 3 degrees within the high flying constellation Cygnus, the eye is drawn to the Cocoon Nebula. A compact star forming region, the cosmic Cocoon punctuates a long trail of obscuring interstellar dust clouds. Cataloged as IC 5146, the nebula is nearly 15 light-years wide, located some 4,000 light years away. Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by the young, hot stars and blue, dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star near the center of this nebula is likely only a few hundred thousand years old, powering the nebular glow as it clears out a cavity in the molecular cloud's star forming dust and gas. But the long dusty filaments that appear dark in this visible light image are themselves hiding stars in the process of formation, seen at infrared wavelengths.
Cloudy Night of the Northern Lights (2011-09-30)
On September 26, a large solar coronal mass ejection smacked into planet Earth's magnetosphere producing a severe geomagnetic storm and wide spread auroras. Captured here near local midnight from Kvaløya island outside Tromsø in northern Norway, the intense auroral glow was framed by parting rain clouds. Tinted orange, the clouds are also in silhouette as the tops of the colorful shimmering curtains of northern lights extend well over 100 kilometers above the ground. Though the auroral rays are parallel, perspective makes them appear to radiate from a vanishing point at the zenith. Near the bottom of the scene, an even more distant Pleiades star cluster and bright planet Jupiter shine on this cloudy northern night.
Asteroids Near Earth (2011-10-01)
Though the sizes are not to scale, the Sun and planets of the inner solar system are shown in this illustration, where each red dot represents an asteroid. New results from NEOWISE, the infrared asteroid hunting portion of the WISE mission, are shown on the left compared to old population projections of mid-size or larger near-Earth asteroids from surveys at visible wavelengths. And the good news is, NEOWISE observations estimate there are 40 percent fewer near-Earth asteroids that are larger than 100 meters (330 feet), than indicated by visible light searches. Based on infrared imaging, the NEOWISE results are more accurate as well. Heated by the Sun, asteroids of the same size radiate the same amount of infrared light, but can reflect very different amounts of visible sunlight depending on how shiny their surface is, or their surface albedo. That effect can bias surveys based on optical observations. NEOWISE results reduce the estimated number of mid-size near-Earth asteroids from about 35,000 to 19,500, but the majority still remain undiscovered.
Tunguska: The Largest Recent Impact Event (2011-10-02)
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.
QR Codes: Not for Human Eyes (2011-10-04)
This communication was not meant for human eyes. It was not even meant for aliens eyes. It's an attempt to communicate directly with your smartphone. Cameras on many smartphones can image the above Quick Response (QR) code and then common applications can tell you what it means.  Sometimes the deciphered code will reveal a web site address, prompting the smartphone to then ask you if you want to access this address to learn more about the object. QR codes are two-dimensional analogs of bar codes that can be scanned in any orientation and tolerate several types of errors. These codes are being used increasingly as doors between real objects and web-based information about those objects, and so are popping up increasingly in unexpected places.  Anyone can create a QR code from any of several free online services, print it out, and affix it to an object. Although not meant to communicate with aliens, QR codes employ several attributes common to famous alien communication attempts.  Can you -- or a local smartphone -- figure out what the above QR code means?
M82: Starburst Galaxy with a Superwind (2011-10-06)
Also known as the Cigar Galaxy for its elongated visual appearance, M82 is a starburst galaxy with a superwind. In fact, through ensuing supernova explosions and powerful winds from massive stars, the burst of star formation in M82 is driving the prodigous outflow of material. Evidence for the superwind from the galaxy's central regions is clear in this sharp composite image, based on data from small telescopes on planet Earth. The composite highlights emission from filaments of atomic hydrogen gas in reddish hues. The filaments extend for over 10,000 light-years. Some of the gas in the superwind, enriched in heavy elements forged in the massive stars, will eventually escape into intergalactic space. Triggered by a close encounter with nearby large galaxy M81, the furious burst of star formation in M82 should last about 100 million years or so. M82 is 12 million light-years distant, near the northern boundary of Ursa Major.   Memorial: Aden Meinel (1922 - 2011 Oct 2), first director of Kitt Peak
The Comet Hartley 2 Cruise (2011-10-07)
rly last November, small but active Comet Hartley 2 (103/P Hartley) became the fifth comet imaged close-up by a spacecraft from planet Earth. Still cruising through the solar system with a 6 year orbital period, Hartley 2 is making astronomical headlines again. New Herschel Space Observatory measurements indicate that the water found in this comet's thin atmosphere or coma has the same ratio of the hydrogen isotope deuterium (in heavy water) as the oceans of our fair planet. Hartley 2 originated in the distant Kuiper Belt, a region beyond the orbit of Neptune that is a reservoir of icy cometary bodies and dwarf planets. Since the ratio of deuterium is related to the solar system environment where the comet formed, the Herschel results indicate that Kuiper Belt comets could have contributed substantial amounts of water to Earth's oceans. Comet Hartley 2 appears in this starry skyscape from last November sporting a tantalizing greenish coma appropriately sailing through the nautical constellation Puppis. Below the comet are open star clusters M47 (right) and M46 (left).