omnianasa/nasa-apod-metadata huggingface dataset:
Mars Soil Sample Ready to Analyze (2008-06-08)
What surprises are hidden in the soils of Mars? To help find out, the Phoenix Lander Phoenix Lander  which arrived on Mars two weeks ago has attempted to place a scoop of soil in Phoenix's Thermal and Evolved-Gas Analyzer (TEGA).  Pictured above, the dirt-filled scoop approaches one of TEGA's eight ovens. Once in the oven, a soil material will be baked and the emitted gasses categorized by a mass spectrometer.  Quite possibly, some of the light colored material visible in the scoop has the same composition as the light material imaged near the foot of the Lander, which may be ice.  Phoenix is scheduled to spend the next three months digging, baking and chemically analyzing its immediate surroundings to better understand Mars and whether the boundary between ice and soil was ever capable of supporting life.
Saturn's Rings from the Other Side (2008-06-09)
What do Saturn's rings look like from the other side?  From Earth, we usually see Saturn's rings from the same side of the ring plane that the Sun illuminates them. Geometrically, in the above picture taken in April by the robot Cassini spacecraft now orbiting Saturn, the Sun is behind the camera but on the other side of the ring plane.  This vantage point, specifically 17 degrees above the ring plane, gives a breathtaking views of the most splendid ring system in the Solar System. Strangely, the rings have similarities to a photographic negative of a front view. The ring brightness as recorded from different angles indicates ring thickness and particle density of ring particles. Elsewhere, ring shadows can be seen on the sunlit face of Saturn, shown sporting numerous cloud structures in nearly true color.
A Fire Rainbow Over New Jersey (2008-06-10)
What is that inverted rainbow in the sky?  Sometimes known as a fire rainbow for its flame-like appearance, a circumhorizon arc is created by ice, not fire.   For a circumhorizon arc to be visible, the Sun must be at least 58 degrees high in a sky where cirrus clouds are present.  Furthermore, the numerous, flat, hexagonal ice-crystals that compose the cirrus cloud must be aligned horizontally to properly refract sunlight like a single gigantic prism.  Therefore, circumhorizon arcs are quite unusual to see.  Pictured above, however, a rare fire rainbow was captured above trees in Whiting, New Jersey, USA in late May.
Dextre Robot at Work on the Space Station (2008-06-11)
What's the world's most complex space robot doing up there?  Last week, Dextre was imaged moving atop the Destiny Laboratory Module of the International Space Station (ISS), completing tasks prior to the deployment of Japan's Kibo pressurized science laboratory. Dextre, short for the Canadian-built Special Purpose Dextrous Manipulator, has arms three meters in length and can attach power tools as fingers.  Behind Dextre is the blackness of space, while Earth looms over Dextre's head.  The Kibo laboratory segment being deployed during space shuttle Discovery's trip to the ISS can be pressurized and contains racks of scientific experiment that will be used to explore many things, including how plants brace themselves against gravity, and how water might be inhibited from freezing in cells under microgravity.    News: GLAST spacecraft reaches orbit
Phoenix and the Snow Queen (2008-06-12)
A flat, smooth, shiny feature dubbed the Snow Queen is near the top of this color mosaic of the surface beneath the Phoenix Mars Lander. Recorded with the lander's robotic arm camera as it was maneuvered to look under the lander, the region also includes a leg and plate-sized footpad. An intriguing detail near the footpad at about the 2 o'clock position, is a metal spring partially buried in martian soil, a piece of the arm's now opened biobarrier. The smooth Snow Queen feature is strongly suspected to be ice originally just under the soil, uncovered by the thruster rockets as Phoenix set down on the north polar plains of Mars. In fact, the apparent holes or depressions in the Snow Queen's otherwise flat surface are located just under the thrusters.
At Last, GLAST (2008-06-13)
Rising through a billowing cloud of smoke, this Delta II rocket left Cape Canaveral Air Force Station's launch pad 17-B Wednesday at 12:05 pm EDT. Snug in the payload section was GLAST, the Gamma-ray Large Area Space Telescope, now in orbit around planet Earth. GLAST's detector technology was developed for use in terrestrial particle accelerators. But from orbit, GLAST can study gamma-rays from extreme environments in our own Milky Way galaxy, as well as supermassive black holes at the centers of distant active galaxies, and the sources of powerful gamma-ray bursts. Those cosmic accelerators achieve energies not attainable in earthbound laboratories. GLAST also has the sensitivity to search for signatures of new physics in the relatively unexplored high-energy gamma-ray regime.
M51 Hubble Remix (2008-06-14)
The 51st entry in Charles Messier's famous catalog is perhaps the original spiral nebula - a large galaxy with a well defined spiral structure also cataloged as NGC 5194. Over 60,000 light-years across, M51's spiral arms and dust lanes clearly sweep in front of its companion galaxy (right), NGC 5195. Image data from the Hubble's Advanced Camera for Surveys has been reprocessed to produce this alternative portrait of the well-known interacting galaxy pair. The processing has further sharpened details and enhanced color and contrast in otherwise faint areas, bringing out dust lanes and extended streams that cross the small companion, along with features in the surroundings and core of M51 itself. The pair are about 31 million light-years distant. Not far on the sky from the handle of the Big Dipper, they officially lie within the boundaries of the small constellation Canes Venatici.
Phoenix Digs for Clues on Mars (2008-06-15)
What's a good recipe for preparing Martian soil? Start by filling your robot's scoop a bit less than half way.  Next, dump your Martian soil into one of your TEGA ovens, being sure to watch out for clumping.  Then, slowly increase the temperature to over 1000 degrees Celsius over several days.  Keep checking to see when your soil becomes vaporized.  Finally, your Martian soil is not ready for eating, but rather sniffing The above technique is being used by the Phoenix Lander that arrived on Mars three weeks ago.  Data from the first batch of baked soil should be available in a few days. Pictured above, a circular array of the Phoenix Lander's solar panels are visible on the left, while a scoop partly filled with Martian soil is visible on the right.  The robotic Phoenix Lander will spend much of the next three months digging, scooping, baking, sniffing, zapping, dissolving, and magnifying bits of Mars to help neighboring Earthlings learn more about the hydrologic and biologic possibilities of the sometimes mysterious red planet.
Inside the Coma Cluster of Galaxies (2008-06-16)
Almost every object in the above photograph is a galaxy.  The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies.  Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy does.  Although nearby when compared to most other clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us.  In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other!  The above mosaic of images of a small portion of Coma was taken in unprecedented detail by the Hubble Space Telescope to investigate how galaxies in rich clusters form and evolve.  Most galaxies in Coma and other clusters are ellipticals, although some imaged here are clearly spirals.   The spiral galaxy on the upper left of the above image can also be found as one of the bluer galaxies on the upper left of this wider field image. In the background thousands of unrelated galaxies are visible far across the universe.    Note: APOD started thirteen years ago today.
Eta Carinae and the Homunculus Nebula (2008-06-17)
How did the star Eta Carinae create this unusual nebula?  No one knows for sure.  About 165 years ago, the southern star Eta Carinae mysteriously became the second brightest star in the night sky.   In 20 years, after ejecting more mass than our Sun, Eta Car unexpectedly faded.  This outburst appears to have created the Homunculus Nebula, pictured above in a composite image from the Hubble Space Telescope taken last decade.  Visible in the above image center is purple-tinted light reflected from the violent star Eta Carinae itself.  Surrounding this star are expanding lobes of gas laced with filaments of dark dust.  Jets bisect the lobes emanating from the central star. Surrounding these lobes are red-tinted debris captured only by its glow in a narrow band of red light.  This debris is expanding most quickly of all, and includes streaming whiskers and bow shocks caused by collisions with previously existing material. Eta Car still undergoes unexpected outbursts, and its high mass and volatility make it a candidate to explode in a spectacular supernova sometime in the next few million years.
Pyramid Ice Crystal Halos Over Finland (2008-06-18)
What if the atmosphere above you became one gigantic lens? This actually happens when a nearly transparent sheet of pyramid shaped ice crystals falls from the sky in a common orientation.  These ice-crystals act together like millions of miniature ice mirrors, with external and internal reflections from different faces creating arcs and halos of different radii.  An amazing display of pyramid ice crystal halos was captured on June 5 above Tampere, Finland.  Visible above are very unusual sun halos of 9, 18, 20, 23, and 24 degrees. In contrast, thin and flat falling ice crystals will produce a halo of 22 degrees only.  The high clouds containing the ice crystals are faintly visible, as are some sundogs.  The usual Sun image was covered behind a light post, and the above image was significantly digitally sharpened.  It is not currently known how large areas of nearly uniform pyramidal ice crystals form.
The Star Streams of NGC 5907 (2008-06-19)
Grand tidal streams of stars seem to surround galaxy NGC 5907. The arcing structures form tenuous loops extending more than 150,000 light-years from the narrow, edge-on spiral, also known as the Splinter or Knife Edge Galaxy. Recorded only in very deep exposures, the streams likely represent the ghostly trail of a dwarf galaxy -- debris left along the orbit of a smaller satellite galaxy that was gradually torn apart and merged with NGC 5907 over four billion years ago. Ultimately this remarkable discovery image, from a small robotic observatory in New Mexico, supports the cosmological scenario in which large spiral galaxies, including our own Milky Way, were formed by the accretion of smaller ones. NGC 5907 lies about 40 million light-years distant in the northern constellation Draco.
Solstice Moonrise, Cape Sounion (2008-06-20)
Today's solstice marks the northernmost point of the Sun's annual motion through planet Earth's sky and the astronomical beginning of the northern hemisphere's summer. But only two days ago, the Full Moon nearest the solstice rose close to the ecliptic plane opposite the Sun, near its southernmost point for the year. Astronomer Anthony Ayiomamitis recorded this dramatic picture of the solstice Full Moon rising above Cape Sounion, Greece. The twenty-four hundred year old Temple of Poseidon lies in the foreground, also visible to sailors on the Aegean Sea. In this well-planned single exposure, a telescopic lens makes the Moon loom large, but even without optical aid casual skygazers often find the Full Moon looking astonishingly large when seen near the horizon. That powerful visual effect is known as the Moon Illusion.
Vanishing Act (2008-06-21)
Compare these two close-up pictures taken on sol 20 (left) and sol 24 of a trench dug in the Martian surface by NASA's Phoenix Lander. Those sols of the Phoenix Mission (a sol is a Martian day), correspond to June 15 and 18 on planet Earth. Light-colored, dice-sized chunks, visible in the lower left shadow region of the trench in the sol 20 image have vanished by sol 24 -- a strong indication that the chunks were ice uncovered by digging the shallow trench. The vanishing act likely demonstrates the sublimation of ice in the trench, a process similar to evaporation, in which the ice went directly from solid to gas after it was exposed to sunlight and the thin, dry Martian atmosphere.
Barred Spiral Galaxy NGC 1300 (2008-06-22)
Big, beautiful, barred spiral galaxy NGC 1300 lies some 70 million light-years away on the banks of the constellation Eridanus. This Hubble Space Telescope composite view of the gorgeous island universe is one of the largest Hubble images ever made of a complete galaxy. NGC 1300 spans over 100,000 light-years and the Hubble image reveals striking details of the galaxy's dominant central bar and majestic spiral arms. In fact, on close inspection the nucleus of this classic barred spiral itself shows a remarkable region of spiral structure about 3,000 light-years across. Unlike other spiral galaxies, including our own Milky Way, NGC 1300 is not presently known to have a massive central black hole.
The International Space Station Expands Again (2008-06-23)
The developing International Space Station (ISS) has changed its appearance again.  Earlier this month, the Space Shuttle orbiter Discovery visited the ISS and added components that included Japan's Kibo Science Laboratory. The entire array of expansive solar panels is visible in this picture taken by the Discovery Crew after leaving the ISS to return to Earth.  The world's foremost space outpost can be seen developing over the past several years by comparing the above image to past images.  Also visible above are many different types of modules, a robotic arm, another impressive set of  solar panels, and a supply ship.  Construction began on the ISS in 1998.
Ithaca Chasma: The Great Rift on Saturn's Tethys (2008-06-24)
What created the Great Rift on Saturn's moon Tethys? No one is sure.  More formally named Ithaca Chasma, the long canyon running across the right of the above image extends about 2,000 kilometers long and spreads as much as 100 kilometers wide. The above image was captured by the Saturn-orbiting robotic Cassini spacecraft as it zoomed by the icy moon last month.  Hypotheses for the formation of Ithaca Chasma include cracking of Tethy's outer crust as the moon cooled long ago, and that somehow the rift is related to the huge Great Basin impact crater named Odysseus, visible elsewhere on the unusual moon.  Cassini has now been orbiting Saturn for about four years and is scheduled to continue to probe and photograph Saturn for at least two more years.
What is Hanny's Voorwerp? (2008-06-25)
What is that green thing? A volunteer sky enthusiast surfing through online Galaxy Zoo images has discovered something really strange. The mystery object is unusually green, not of any clear galaxy type, and situated below relatively normal looking spiral galaxy IC 2497. Dutch schoolteacher Hanny van Arkel, discovered the  strange green "voorwerp" (Dutch for "object") last year. The Galaxy Zoo project encourages sky enthusiasts to browse through SDSS images and classify galaxy types.  Now known popularly as Hanny's Voorwerp, subsequent observations have shown that the mysterious green blob has the same distance as neighboring galaxy IC 2497.  Research is ongoing, but one leading hypothesis holds that Hanny's Voorwerp is a small galaxy that acts like a large reflection nebula, showing the reflected light of a bright quasar event that was visible in the center of IC 2497 about 100,000 years ago.   Pictured above, Hanny's Voorwerp was imaged recently by the 2.5-meter Isaac Newton Telescope in the Canary Islands by Dan Smith, Peter Herbert and Chris Lintott (Univ. Hertfordshire). Other collaboration members include Matt Jarvis, Kevin Schawinski, and William Keel.
M27: Not A Comet (2008-06-26)
Born on June 26th in 1730, astronomer Charles Messier scanned 18th century French skies for comets. To avoid confusion and aid his comet hunting, he diligently recorded this object as number 27 on his list of things which are definitely not comets. In fact, 21st century astronomers would classify it as a Planetary Nebula, but it's not a planet either, even though it may appear round and planet-like in a small telescope. Messier 27 (M27) is now known to be an excellent example of a gaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light. Known by the popular name of the Dumbbell Nebula, the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula. This impressive color composite highlights subtle jet features in the nebula. It was recorded with a robotic telescope sited in Hawaii using narrow band filters sensitive to emission from oxygen atoms (shown in green) and hydrogen atoms. The hydrogen emission is seen as red (H-alpha) and fainter bluish hues (H-beta).
M81: Feeding a Black Hole (2008-06-27)
This impressive color composite shows spiral galaxy M81 across the electromagnetic spectrum. It combines X-ray data (blue) from the Chandra Observatory, infrared data (pink) from the Spitzer Space Telescope, and an ultraviolet image (purple) from the GALEX satellite, with a visible light (green) Hubble image. The inset highlights X-rays from some of M81's black holes, including black holes in binary star systems with about 10 times the mass of the sun, as well as the central, supermassive black hole of over 70 million solar masses. Comparing computer models of the giant black hole's energy output to the multiwavelength data suggests that feeding that monster is relatively simple -- energy and radiation is generated as material in the central region swirls inwards forming an accretion disk. In fact, the process otherwise appears to be just like the accretion process feeding M81's stellar mass black holes, even though the central black hole is millions of times more massive. M81 itself is about 70,000 light-years across and only 12 million light-years away in the northern constellation Ursa Major.
Fireball at Ayers Rock (2008-06-28)
A weekend trip for astrophotography in central Australia can result in gorgeous skyscapes. In this example recorded in March of 2006, the center of our Milky Way Galaxy rises over planet Earth's horizon and the large sandstone formation called Uluru, also known as Ayers Rock. After setting up two cameras to automatically image this celestial scene in a series of exposures, one through a wide-angle and the other through a telephoto lens, photographer Joseph Brimacombe briefly turned his back to set up other equipment. To his surprise, the ground around him suddenly lit up with the brilliant flash of a fireball meteor. To his delight, both cameras captured the bright meteor streak. Highlighted in the telephoto view (inset), the fireball trail shines through cloud banks, just left of Ayers Rock.
Shadow of a Martian Robot (2008-06-29)
What if you saw your shadow on Mars and it wasn't human?  Then you might be the  Opportunity rover currently exploring Mars.  Opportunity and sister robot Spirit have been probing the red planet since early 2004, finding evidence of ancient water, and sending breathtaking images across the inner Solar System.  Pictured above, Opportunity looks opposite the Sun into Endurance Crater and sees its own  shadow.  Two wheels are visible on the lower left and right, while the floor and walls of the unusual crater are visible in the background.  Opportunity and Spirit have now spent over four years exploring the red world, find new clues into the wet ancient past of our Solar System's second most habitable planet.
In the Center of the Trifid Nebula (2008-06-30)
Clouds of glowing gas mingle with dust lanes in the Trifid Nebula, a star forming region toward the constellation of Sagittarius.  In the center, the three prominent dust lanes that give the Trifid its name all come together. Mountains of opaque dust appear on the right, while other dark filaments of dust are visible threaded throughout the nebula.  A single massive star visible near the center causes much of the Trifid's glow.  The Trifid, also known as M20, is only about 300,000 years old, making it among the youngest emission nebulae known.  The nebula lies about 9,000 light years away and the part pictured here spans about 10 light years.  This image was created with the 0.8-meter IAC80 telescope on the Canary Islands of Spain.
Pickering's Triangle from Kitt Peak (2008-07-01)
Wisps like this are all that remain visible of a Milky Way star.  About 7,500 years ago that star exploded in a supernova leaving the Veil Nebula, also known as the Cygnus Loop. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history.  Today, the resulting supernova remnant has faded and is now visible only through a small telescope directed toward the constellation of Cygnus. The remaining Veil Nebula is physically huge, however, and even though it lies about 1,400 light-years distant, it covers over five times the size of the full Moon.  In images of the complete Veil Nebula, studious readers should be able to identify the Pickering's Triangle component pictured above, a component named for a famous astronomer and the wisp's approximate shape.  The above image is a mosaic from the 4-meter Mayall telescope at the Kitt Peak National Observatory located in Arizona, USA.
Night Shinings (2008-07-02)
In the early morning hours of June 30th, ghostly clouds hovered in the east in this view of near dawn skies over western France. The noctilucent or night-shining clouds lie near the edge of space, reflecting sunlight from about 80 kilometers above Earth's surface. Usually spotted above the poles in summer, they are now seen with increasing frequency farther from the poles, in this case extending to the photographer's latitude of about 48 degrees north. The trend could be a telltale sign of global changes in the atmosphere. Another 400,000 kilometers away, the Moon's sunlit crescent shines brightly, its night side illuminated by Earthshine. Of course, as a bonus for early risers June's old crescent Moon was followed closely across the sky by the lovely Pleiades star cluster, surrounded by cosmic dust clouds and shining from a mere 400 light-years away.
Hoodoo Sky (2008-07-03)
The strange-looking rock formations in the foreground of this skyscape are called hoodoos. Towers of weathered, eroded sedimentary rock, hoodoos are found in arid regions of planet Earth and are particularly abundant in an area known as Bryce Canyon National Park in southern Utah, USA. The more familiar night sky pictured here was recorded early Monday morning and includes bright star Capella, alpha star of the constellation Auriga, left of center. On the far right, a very over exposed crescent Moon dominates the sky in close conjunction with the sister stars of the Pleiades cluster. The curious shapes of the two tall, illuminated hoodoos suggest their popular monikers; Thor's Hammer (right) and The Temple of Osiris.