omnianasa/nasa-apod-metadata huggingface dataset:
The Nearby Milky Way in Cold Dust (2010-03-22)
What shapes the remarkable dust tapestry of the nearby Milky Way Galaxy? No one knows for sure.  The intricate structures, shown above, were resolved in new detail recently in a wide region of the sky imaged in far infrared light by the European Space Agency's Planck satellite. The above image is a digital fusion of three infrared colors: two taken at high resolution by Planck, while the other is an older image taken by the now defunct IRAS satellite. At these colors, the sky is dominated by the faint glow of very cold gas within only 500 light years of Earth. In the above image, red corresponds to temperatures as cold as 10 degrees Kelvin above absolute zero, while white corresponds to gas as warm at 40 Kelvins. The pink band across the lower part of the image is warm gas confined to the plane of our Galaxy. The bright regions typically hold dense molecular clouds that are slowly collapsing to form stars, whereas the dimmer regions are most usually diffuse interstellar gas and dust known as cirrus.  Why these regions have intricate filamentary shapes shared on both large and small scales remains a topic of research. Future study of the origin and evolution of dust may help in the understanding the recent history of our Galaxy as well as how planetary systems such as our Solar System came to be born.
Reinvigorated Sun and Prominence (2010-03-23)
Dramatic prominences can sometimes be seen looming just beyond the edge of the sun.  Such was the case last week as a giant prominence, visible above on the right, highlighted a Sun showing increased activity as it comes off an unusually quiet Solar Minimum.  A changing carpet of hot gas is visible in the chromosphere of the Sun in the above image taken in a very specific color of light emitted by hydrogen. A solar prominence is a cloud of solar gas held just above the surface by the Sun's magnetic field. The Earth would easily fit below the prominence on the right. Although very hot, prominences typically appear dark when viewed against the Sun, since they are slightly cooler than the surface.  A quiescent prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System.  The next day, the same prominence looked slightly different.
Galaxy Wars: M81 versus M82 (2010-03-24)
On the right, surrounded by blue spiral arms, is spiral galaxy M81.  On the left, marked by red gas and dust clouds, is irregular galaxy M82.  This stunning vista shows these two mammoth galaxies locked in gravitational combat, as they have been for the past billion years.   The gravity from each galaxy dramatically affects the other during each hundred million-year pass.  Last go-round, M82's gravity likely raised density waves rippling around M81, resulting in the richness of M81's spiral arms.  But M81 left M82 with violent star forming regions and colliding gas clouds so energetic the galaxy glows in X-rays.  In a few billion years only one galaxy will remain.
NGC 2442: Galaxy in Volans (2010-03-25)
Distorted galaxy NGC 2442 can be found in the southern constellation of the flying fish, (Piscis) Volans. Located about 50 million light-years away, the galaxy's two spiral arms extending from a pronounced central bar have a hook-like appearance in wide-field images. But this mosaicked close-up, constructed from Hubble Space Telescope data, follows the galaxy's structure in amazing detail. Obscuring dust lanes, young blue star clusters and reddish star forming regions surround a core of yellowish light from an older population of stars. The sharp Hubble data also reveal more distant background galaxies seen right through NGC 2442's star clusters and nebulae. The image spans about 75,000 light-years at the estimated distance of NGC 2442.
Young Moon and Sister Stars (2010-03-26)
A young crescent Moon shares the western sky with sister stars of the Pleiades cluster in this pretty, evening skyscape recorded on the March equinox from San Antonio, Texas.  In the processed digital image, multiple exposures of the celestial scene were combined to show details of the bright lunar surface along with the Pleiades stars. Astronomical images of the well-known Pleiades often show the cluster's alluring blue reflection nebulae, but they are washed-out here in the bright moonlight. Still, during this particular night, skygazers in South and Central America could even watch the 5 day old Moon occult or pass in front of some of the brighter Pleiades stars.
Hesiodus Sunrise Ray (2010-03-27)
Stark shadows of mountains and crater walls stand out along the lunar terminator, or shadow line between night and day, in this telescopic image. Of course, if viewed from the lunar surface near the terminator line, the Sun would be rising and still close to the lunar horizon. But the picture's inset at the left highlights a more elusive lunar sunrise phenomenon. Streaming through a gap in the eastern wall of 45 kilometer wide Hesiodus crater, the low-angle sunlight produces a long sunrise ray playing along the otherwise shadowed crater floor. Sunrise rays are short-lived and can be rewarding to spot for Moon enthusiasts with telescopes. Seen in Hesiodus and other craters, the ray timing can be calculated based on the observer's location. This picture of a first quarter Moon was recorded at 23:45 UT on February 22nd from Stuttgart, Germany. In the inset, the larger crater Pitatus is at the right. For location, Hesiodus and Pitatus are circled at the bottom of the picture.
M16: Pillars of Creation (2010-03-28)
It has become one of the most famous images of modern times. This image, taken with the Hubble Space Telescope in 1995, shows evaporating gaseous globules (EGGs) emerging from pillars of molecular hydrogen gas and dust. The giant pillars are light years in length and are so dense that interior gas contracts gravitationally to form stars. At each pillars' end, the intense radiation of bright young stars causes low density material to boil away, leaving stellar nurseries of dense EGGs exposed.  The Eagle Nebula, associated with the open star cluster M16, lies about 7000 light years away. The pillars of creation were again imaged by the orbiting Chandra X-ray Observatory, and it was found that most EGGS are not strong emitters of X-rays.
Moonset Over Pleasant Bay (2010-03-29)
It was a sky for the imagination. In the early evening last week, the sky illuminating the unaided eye was perhaps even more illuminating to the mind's eye.  The unaided eye saw clouds framing the Moon setting over a calm and reflective bay, spruce trees lining the nearby shores, the Pleiades open star cluster (M45) glowing prominently in the center of the sky, the Andromeda galaxy hovering just over the horizon on the right, and the belt stars of Orion lined up on the left, just below the bright orange star Betelgeuse.  The bright star Sirius peeked out of the trees on the far left.  The mind's eye might further imagine, however, some of the constellations coming to life, with Orion the Hunter taking up his sword and shield, followed into battle by his Big Dog  (Canis Major, whose right eye is Sirius), and watched from across the sky by Cassiopeia, the Queen of Ethiopia, sitting on her Throne.  The above image was taken over Pleasant Bay, Maine, USA, and digitally merged with constellations from Uranographicarum, drawn in the 17th century by J. Hevelius.
Unusual Starburst Galaxy NGC 1313 (2010-03-30)
Why is this galaxy so discombobulated?  Usually, galaxies this topsy-turvy result from a recent collision with a neighboring galaxy. Spiral galaxy NGC 1313, however, appears to be alone.  Brightly lit with new and blue massive stars, star formation appears so rampant in NGC 1313 that it has been labeled a starburst galaxy.  Strange features of NGC 1313 include that its spiral arms are lopsided and its rotational axis is not at the center of the nuclear bar.  Pictured above, NGC 1313 spans about 50,000 light years and lies only about 15 million light years away toward the constellation of the Reticle (Reticulum). Continued numerical modeling of galaxies like NGC 1313 might shed some light on its unusual nature.
Millions of Stars in Omega Centauri (2010-03-31)
Featured in the sharp telescopic image, globular star cluster Omega Centauri (NGC 5139) is some 15,000 light-years away and 150 light-years in diameter. Packed with about 10 million stars much older than the Sun, Omega Cen is the largest of 200 or so known globular clusters that roam the halo of our Milky Way galaxy. Though most star clusters consist of stars with the same age and composition, the enigmatic Omega Cen exhibits the presence of different stellar populations with a spread of ages and chemical abundances. In fact, Omega Cen may be the remnant core of a small galaxy merging with the Milky Way.
Evidence Mounts for Water on the Moon (2010-04-01)
In 2009, space missions revealed tantalizing signs of water on or near the lunar surface, once thought of as a dry and desolate environment. But researchers are now offering this archival picture as further evidence that humans might one day be able to use the Moon's newly discovered resource to directly quench their thirst. Found in a pile of old Apollo lunar surface photographs, the picture reveals an object at the far left of the frame that appears to be a drinking fountain, surprisingly close to one of the Lunar Module landing struts. When asked why no mention of the object was in their reports, the astronauts replied that they discovered their spacesuit gloves were too bulky to allow them to activate the fountain, so they had simply ignored it during their stay on the lunar surface. Perhaps not coincidentally, this picture was taken exactly 40 years ago, on April Fools Day ...
Serene Paraselene (2010-04-02)
Nestled in the Austrian Alps, frozen Lake Ossiach stretches across the foreground of this serene view. Recorded on March 1, the night sky includes a nearly full Moon and bright planet Saturn seen through thin clouds near picture center. It also includes a remarkably bright and colorful moondog or paraselene at the left. Analogous to a sundog or parhelion, the paraselene is produced by moonlight shining through thin, hexagonal-shaped ice crystals in high cirrus clouds. As determined by the ice crystal geometry, the Moon is 22 degrees from the lovely paraselene.
NGC 602 and Beyond (2010-04-03)
Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the region. Fantastic ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster's center. At the estimated distance of the Small Magellanic Cloud, the picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in the sharp Hubble view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.
The Belt of Venus over the Valley of the Moon (2010-04-04)
Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink. Called the Belt of Venus, this off-color band between the dark eclipsed sky and the blue sky can be seen in nearly every direction including that opposite the Sun.  Straight above, blue sky is normal sunlight reflecting off the atmosphere. In the Belt of Venus, however, the atmosphere reflects light from the setting (or rising) Sun which appears more red.  The Belt of Venus can be seen from any location with a clear horizon. Pictured above, the Belt of Venus was photographed above morning fog in the Valley of the Moon, a famous wine-producing region in northern California, USA. The belt is frequently caught by accident in other photographs.
Prometheus Remastered (2010-04-05)
What does Saturn's shepherd moon Prometheus really look like? The raw images from the robotic Cassini spacecraft's January flyby of the small moon showed tantalizing clues on grainy images, but now that the Cassini team has digitally remastered these images, many more details have come out. Pictured above, Prometheus more clearly shows its oblong shape as well as numerous craters over its 100-kilometer length. In the above image, the bright part of Prometheus is lit directly by the Sun, while much of the dark part is still discernible through sunlight first reflected off of Saturn. These new surface details, together with the moon's high reflectivity, can now help humanity better understand the history of Prometheus and Saturn's rings. Today, Cassini has a planned targeted flyby of Saturn's largest moon Titan, while on Wednesday, Cassini is scheduled to swoop to within 600 kilometers of Dione.
A Fox Fur, a Unicorn, and a Christmas Tree (2010-04-06)
What do the following things have in common: a cone, the fur of a fox, and a Christmas tree?  Answer: they all occur in the constellation of the unicorn (Monoceros). Pictured above as a star forming region cataloged as NGC 2264, the complex jumble of cosmic gas and dust is about 2,700 light-years distant and mixes reddish emission nebulae excited by energetic light from newborn stars with dark interstellar dust clouds. Where the otherwise obscuring dust clouds lie close to the hot, young stars they also reflect starlight, forming blue reflection nebulae. The wide mosaic spans about 3/4 degree or nearly 1.5 full moons, covering 40 light-years at the distance of NGC 2264. Its cast of cosmic characters includes the Fox Fur Nebula, whose convoluted pelt lies at the upper left, bright variable star S Mon immersed in the blue-tinted haze just below the Fox Fur, and the Cone Nebula at the far right. Of course, the stars of NGC 2264 are also known as the Christmas Tree star cluster. The triangular tree shape traced by the stars appears sideways here, with its apex at the Cone Nebula and its broader base centered near S Mon.
Venus and Mercury in the West (2010-04-07)
In this twilight skyview, a windmill stands in silent witness to a lovely pairing of planets in the west. The picture was recorded on April 5 from Gallegos del Campo, Zamora, Spain. Venus (left) and Mercury (right) are near their much anticipated conjunction in the early evening sky. But even in the coming days, these two evening stars will remain close in the western sky at sunset. In fact, with brighter Venus as a marker, sky watchers will have an excellent guide for spotting Mercury nearby, a planet often hidden in the Sun's glare.
Discovery's Cloud (2010-04-08)
The space shuttle orbiter Discovery is now docked with the International Space Station, some 350 kilometers above planet Earth. Last Monday, its launch to orbit was a beautiful one as it rose into clear, predawn skies at 6:21am EDT from Kennedy Space Center's pad 39A. Looking east, this time exposure was taken shortly after lift off from a marina about 13 miles west of the launch site in Titusville, Florida. It shows the dawn's emerging colors along the horizon, with wafting rocket contrails at the upper right. The bright streak surrounded by the remarkable, elongated, vapor cloud near the center of the image is the actual track of Discovery, arcing toward the horizon and its orbital rendezvous.
Discovery's Dawn (2010-04-09)
On April 5, visitors to Kennedy Space Center saw these colorful clouds, twisting and drifting through dawn skies. Of course, the clouds were rocket engine plumes from the predawn launch of the space shuttle Discovery on the STS-131 mission to the International Space Station. Their layered colors are created as they reflect the reddened light from the still rising Sun. Fittingly, denizens of the space center's rocket garden are lit in the foreground. At the far left is a 1960s vintage multistage Atlas-Agena rocket. Together on the right, are Mercury-Redstone and Mercury-Atlas rockets.
Spitzer's Orion (2010-04-10)
Few cosmic vistas excite the imagination like the Orion Nebula, an immense stellar nursery some 1,500 light-years away. Spanning about 40 light-years across the region, this new infrared image from the Spitzer Space Telescope was constructed from data intended to monitor the brightness of the nebula's young stars, many still surrounded by dusty, planet-forming disks. Orion's young stars are only about 1 million years old, compared to the Sun's age of 4.6 billion years. The region's hottest stars are found in the Trapezium Cluster, the brightest cluster near picture center. Spitzer's liquid helium coolant ran out in May 2009, so this false color view is from two channels that still remain sensitive to infrared light at warmer operating temperatures.
IC 418: The Spirograph Nebula (2010-04-11)
What is creating the strange texture of IC 418?  Dubbed the Spirograph Nebula for its resemblance to drawings from a cyclical drawing tool, planetary nebula IC 418 shows patterns that are not well understood. Perhaps they are related to chaotic winds from the variable central star, which changes brightness unpredictably in just a few hours.  By contrast, evidence indicates that only a few million years ago, IC 418 was probably a well-understood star similar to our Sun.  Only a few thousand years ago, IC 418 was probably a common red giant star.  Since running out of nuclear fuel, though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white-dwarf star, visible in the image center. The light from the central core excites surrounding atoms in the nebula causing them to glow. IC 418 lies about 2000 light-years away and spans 0.3 light-years across.  This false-color image taken from the Hubble Space Telescope reveals the unusual details.
Mercury and Venus Over Paris (2010-04-12)
Go outside tonight and see one of the more interesting planetary conjunctions of recent years.  Just after sunset, the planets Mercury and Venus are visible quite near each other. Now Venus, being commonly discernible as one of the brightest objects in the sky, is frequently mistaken for an airplane. (Venus will set quite slowly, though.) Mercury, however, is dimmer and usually harder to find. Recently, though, Mercury can be found just to the right of Venus, appearing increasingly below the brighter planet over the next week. Pictured above, Venus and Mercury were imaged next to the famous Notre Dame Cathedral in Paris, France.  A careful inspection of the image will further reveal that the bright object nearly below Venus is iconic Eiffel Tower.
Unusual Spiral Galaxy M66 from Hubble (2010-04-13)
Why isn't spiral galaxy M66 symmetric?  Usually density waves of gas, dust, and newly formed stars circle a spiral galaxy's center and create a nearly symmetric galaxy.  The differences between M66's spiral arms and the apparent displacement of its nucleus are all likely caused by previous close interactions and the tidal gravitational pulls of nearby galaxy neighbors M65 and NGC 3628. Spiral galaxy M66, pictured above, spans about 100,000 light years, lies about 35 million light years distant, and is the largest galaxy in a group known as the Leo Triplet.  Like many spiral galaxies, the long and intricate dust lanes of M66 are seen intertwined with the bright stars and nebulas that light up the spiral arms.
A Large Space Station Over Earth (2010-04-14)
The International Space Station is the largest object ever constructed by humans in space.  The station perimeter now extends over roughly the area of a football field, although only a small fraction of this is composed of modules habitable by humans. The station is so large that it could not be launched all at once -- it is being built piecemeal with large sections added continually by flights of the Space Shuttle.  To function, the ISS needs huge trusses, some over 15 meters long and with masses over 10,000 kilograms, to keep it rigid and to route electricity and liquid coolants.  Pictured above, part of the immense space station was photographed out of a window by a member of the visiting Space Shuttle Discovery STS-131 crew. Visible in the foreground is Japan's Kibo research module, while a large truss is visible toward the left.  On the far right, a crescent Earth slices through the blackness of space.
NGC 4651: The Umbrella Galaxy (2010-04-15)
Spiral galaxy NGC 4651 is a mere 35 million light-years distant, toward the well-groomed constellation Coma Berenices. About 50 thousand light-years across, this galaxy is seen to have a faint umbrella-shaped structure (right) that seems to extend some 50 thousand light-years farther, beyond the bright galactic disk. The giant cosmic umbrella is now known to be composed of tidal star streams. The streams themselves are extensive trails of stars gravitationally stripped from a smaller satellite galaxy that was eventually torn apart. Placing your cursor over the image will superimpose a simulation of the satellite galaxy's path as it was disrupted and absorbed into NGC 4651. Recent work by a remarkable collaboration of amateur and professional astronomers to image faint structures around bright galaxies suggests that even in nearby galaxies, such tidal star streams are common. The result is predicted by models of galaxy formation, including the formation of our Milky Way.
Bright Points on the Quiet Sun (2010-04-16)
Up close, the solar surface is a striking patch work of granules in this very high resolution picture of the quiet Sun. Caused by convection, the granules are hot, rising columns of plasma edged by dark lanes of cooler, descending plasma. But the high-resolution view reveals that the dark lanes are dotted with many small, contrasting bright points. Constantly present on the solar surface, the bright points do not seem to be related to sunspots that come and go with the magnetic solar cycle. Nonetheless, the bright points are regions of concentrated magnetic fields and are bright because the magnetic pressure opens a window to hotter deeper layers below the photosphere. For scale, the white bar at the lower left corresponds to 5,000 kilometers across the Sun's surface. The sharp, narrow-band image was recorded in September, 2007 using the Swedish Solar Telescope on the astronomical island of La Palma.
Damage to Apollo 13 (2010-04-17)
After an oxygen tank exploded and crippled their service module, the Apollo 13 astronauts were forced to abandon plans to make the third manned lunar landing. The extent of the damage is revealed in this grainy, grim photo, taken as the service module was drifting away, jettisoned only hours prior to the command module's reentry and splashdown. An entire panel on the side of the service module has been blown away and extensive internal damage is apparent. Visible below the gutted compartment is a radio antenna and the large, bell-shaped nozzle of the service module's rocket engine. On April 17, 1970 the three astronauts returned safely to Earth.
Large Eruptive Prominence Imaged by STEREO (2010-04-18)
What's happened to our Sun?  Last week, it produced one of the largest eruptive prominences ever seen. Pictured above, the prominence erupted in only a few hours and was captured in movie form by NASA's twin Sun-orbiting STEREO satellites.  A quiescent solar prominence is a cloud of hot solar gas held above the Sun's surface by the Sun's magnetic field.  Unpredictably, however, prominences may erupt,   expelling hot gas into the Solar System via a  Coronal Mass Ejection (CME). As pictured above, many Earths would easily fit under the expanding ribbon of hot gas.  Although somehow related to the Sun's changing magnetic field, the energy mechanism that creates and sustains a Solar prominence is still a topic of research.