omnianasa/nasa-apod-metadata huggingface dataset:
Ganymede's Shadow (2017-03-25)
Approaching opposition early next month, Jupiter is offering some of its best telescopic views from planet Earth. On March 17, this impressively sharp image of the solar system's ruling gas giant was taken from a remote observatory in Chile. Bounded by planet girdling winds, familiar dark belts and light zones span the giant planet spotted with rotating oval storms. The solar system's largest moon Ganymede is above and left in the frame, its shadow seen in transit across the northern Jovian cloud tops. Ganymede itself is seen in remarkable detail along with bright surface features on fellow Galilean moon Io, right of Jupiter's looming disk.
Tardigrade in Moss (2017-03-26)
Is this an alien?  Probably not, but of all the animals on Earth, the tardigrade might be the best candidate. That's because tardigrades are known to be able to go for decades without food or water, to survive temperatures from near absolute zero to well above the boiling point of water, to survive pressures from near zero to well above that on ocean floors, and to survive direct exposure to dangerous radiations.  The far-ranging survivability of these extremophiles was tested in 2011 outside an orbiting space shuttle. Tardigrades are so durable partly because they can repair their own DNA and reduce their body water content to a few percent. Some of these miniature water-bears almost became  extraterrestrials recently when they were launched toward to the Martian moon Phobos on board the Russian mission Fobos-Grunt, but stayed terrestrial when a rocket failed and the capsule remained in Earth orbit.  Tardigrades are more common than humans across most of the Earth. Pictured here in a color-enhanced electron micrograph, a millimeter-long tardigrade crawls on moss.
Black Hole Accreting with Jet (2017-03-27)
What happens when a black hole devours a star?  Many details remain unknown, but recent observations are providing new clues. In 2014, a powerful explosion was recorded by the ground-based robotic telescopes of the All Sky Automated Survey for SuperNovae (ASAS-SN) project, and followed up by instruments including NASA's Earth-orbiting Swift satellite. Computer modeling of these emissions fit a star being ripped apart by a distant supermassive black hole.  The results of such a collision are portrayed in the featured artistic illustration. The black hole itself is a depicted as a tiny black dot in the center. As matter falls toward the hole, it collides with other matter and heats up. Surrounding the black hole is an accretion disk of hot matter that used to be the star, with a jet emanating from the black hole's spin axis.
King of Wings Hoodoo under the Milky Way (2017-03-28)
This rock structure is not only surreal -- it's real.  The reason it's not more famous is that it is, perhaps, smaller than one might guess: the capstone rock overhangs only a few meters.  Even so, the King of Wings outcrop, located in New Mexico, USA, is a fascinating example of an unusual type of rock structure called a hoodoo. Hoodoos may form when a layer of hard rock overlays a layer of eroding softer rock. Figuring out the details of incorporating this hoodoo into a night-sky photoshoot took over a year. Besides waiting for a suitably picturesque night behind a sky with few clouds, the foreground had to be artificially lit just right relative to the natural glow of the background.  After much planning and waiting, the final shot, featured here, was taken in May 2016. Mimicking the horizontal bar, the background sky features the band of our Milky Way Galaxy stretching overhead.
Nebula with Laser Beams (2017-03-29)
Four laser beams cut across this startling image of the Orion Nebula, as seen from ESO's Paranal Observatory in the Atacama desert on planet Earth. Not part of an interstellar conflict, the lasers are being used for an observation of Orion by UT4, one of the observatory's very large telescopes, in a technical test of an image-sharpening adaptive optics system. This view of the nebula with laser beams was captured by a small telescope from outside the UT4 enclosure. The beams are visible from that perspective because in the first few kilometers above the observatory the Earth's dense lower atmosphere scatters the laser light. The four small segments appearing beyond the beams are emission from an atmospheric layer of sodium atoms excited by the laser light at higher altitudes of 80-90 kilometers. Seen from the perspective of the UT4, those segments form bright spots or artificial guide stars. Their fluctuations are used in real-time to correct for atmospheric blurring along the line-of-sight by controlling a deformable mirror in the telescope's optical path.
Young Stars and Dusty Nebulae in Taurus (2017-03-30)
This complex of dusty nebulae lingers along the edge of the Taurus molecular cloud, a mere 450 light-years distant. Stars are forming on the cosmic scene. Composed from almost 40 hours of image data, the 2 degree wide telescopic field of view includes some youthful T-Tauri class stars embedded in the remnants of their natal clouds at the right. Millions of years old and still going through stellar adolescence, the stars are variable in brightness and in the late phases of their gravitational collapse. Their core temperatures will rise to sustain nuclear fusion as they grow into stable, low mass, main sequence stars, a stage of stellar evolution achieved by our middle-aged Sun about 4.5 billion years ago. Another youthful variable star, V1023 Tauri, can be spotted on the left. Within its yellowish dust cloud, it lies next to the striking blue reflection nebula Cederblad 30, also known as LBN 782. Just above the bright bluish reflection nebula is dusty dark nebula Barnard 7.
3D 67P (2017-03-31)
Get out your red/cyan glasses and gaze across the surface of Churyumov-Gerasimenko, aka Comet 67P. The stereo anaglyph was created by combining two images from the Rosetta spacecraft's narrow angle OSIRIS camera taken on September 22, 2014. Stark and jagged, the 3D landscape is found along the Seth region of the comet's double-lobed nucleus. It spans about 985 x 820 meters, pocked by circular ridges, depressions, and flattened areas strewn with boulders and debris. The large steep-walled circular pit in the foreground is 180 meters in diameter. Rosetta's mission to the comet ended in September 2016 when the spacecraft was commanded to a controlled impact with the comet's surface.
Split the Universe (2017-04-01)
Just now, before you hit the button, two future universes are possible.  After pressing the button, though, you will live in only one.  A real-web version of the famous Schr�dinger's cat experiment, clicking the red button in the featured astronaut image should transform that image into a picture of the same astronaut holding one of two cats -- one living, or one dead.  The timing of your click, combined with the wiring of your brain and the millisecond timing of your device, will all conspire together to create a result dominated, potentially, by the randomness of quantum mechanics.  Some believe that your personally-initiated quantum decision will split the universe in two, and that both the live-cat and dead-cat universes exist in separate parts of a larger multiverse. Others believe that the result of your click will collapse the two possible universes into one -- in a way that could not have been predicted beforehand.  Yet others believe that the universe is classically deterministic, so that by pressing the button you did not really split the universe, but just carried out an action predestined since time began.   We at APOD believe that however foolish you may feel clicking the red button, and regardless of the outcome,  you should have a happy April Fool's Day.
NGC 602 and Beyond (2017-04-02)
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, augmented by images in the X-ray by Chandra,  and in the infrared by Spitzer. 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 this sharp multi-colored view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.    Open Science: Browse 1,400+ codes in the Astrophysics Source Code Library
Saturn in Infrared from Cassini (2017-04-03)
Many details of Saturn appear clearly in infrared light.  Bands of clouds show great structure, including long stretching storms.  Also quite striking in infrared is the unusual hexagonal cloud pattern surrounding Saturn's North Pole.  Each side of the dark hexagon spans roughly the width of our Earth. The hexagon's existence was not predicted, and its origin and likely stability remains a topic of research.  Saturn's famous rings circle the planet and cast shadows below the equator. The featured image was taken by the robotic Cassini spacecraft in 2014 in several infrared colors -- but only processed recently.  In September, Cassini's mission will be brought to a dramatic conclusion as the spacecraft will be directed to dive into ringed giant.
Plane Contrail and Sun Halo (2017-04-04)
What's happened to the sky? Several common features of the daytime sky are interacting in uncommon ways.  First, well behind the silhouetted hills, is the typically bright Sun.  In front of the Sun are thin clouds, possibly the home to a layer of hexagonal ice crystals that together are creating the 22 degree halo of light surrounding the Sun. The unusual bent line that crosses the image is a contrail -- a type of cloud created by a passing airplane. Much of the contrail must actually be further away than the thin cloud because it casts a shadow onto the cloud, giving an unusual three-dimensional quality to the featured image. The featured image was taken in late January in the city of Patras in West Greece.
Filaments of Active Galaxy NGC 1275 (2017-04-05)
What keeps these filaments attached to this galaxy?  The filaments persist in NGC 1275 even though the turmoil of galactic collisions should destroy them. First,  active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies. Wild-looking at visible wavelengths, the active galaxy is also a prodigious source of x-rays and radio emission. NGC 1275 accretes matter as entire galaxies fall into it, ultimately feeding a supermassive black hole at the galaxy's core. This composite image, recreated from archival Hubble Space Telescope data, highlights the resulting galactic debris and filaments of glowing gas, some up to 20,000 light-years long. Observations indicate that the structures, pushed out from the galaxy's center by the black hole's activity, are held together by magnetic fields. Also known as Perseus A, NGC 1275 spans over 100,000 light years and lies about 230 million light years away.
Dark Nebula LDN 1622 and Barnard's Loop (2017-04-06)
The silhouette of an intriguing dark nebula inhabits this cosmic scene. Lynds' Dark Nebula (LDN) 1622 appears below center against a faint background of glowing hydrogen gas only easily seen in long telescopic exposures of the region. LDN 1622 lies near the plane of our Milky Way Galaxy, close on the sky to Barnard's Loop - a large cloud surrounding the rich complex of emission nebulae found in the Belt and Sword of Orion. Arcs along a segment of Barnard's loop stretch across the top of the frame. But the obscuring dust of LDN 1622 is thought to be much closer than Orion's more famous nebulae, perhaps only 500 light-years away. At that distance, this 1 degree wide field of view would span less than 10 light-years.
Castle Eye View (2017-04-07)
The best known asterism in northern skies, The Big Dipper is easy to recognize, even when viewed upside down, though some might see a plough or wagon. The star names and the familiar outlines appear framed in the ruined tower walls of the French Chateau du Morimont if you just slide your cursor over the image or follow this link. Dubhe, alpha star of the dipper's parent constellation Ursa Major is at the lower left. Together with beta star Merak the two form a line pointing the way to Polaris and the North Celestial Pole, hidden from view by the stones. Since the image was captured on March 30, you can follow a line from dipper stars Phecda and Megrez to spot the faint greenish glow of Comet 41P/Tuttle-Giacobini-Kresak below center, still within the castle eye view. The periodic comet made a remarkable close approach to planet Earth on April 1.
Zeta Oph: Runaway Star (2017-04-08)
Like a ship plowing through cosmic seas, runaway star Zeta Ophiuchi produces the arcing interstellar bow wave or bow shock seen in this stunning infrared portrait. In the false-color view, bluish Zeta Oph, a star about 20 times more massive than the Sun, lies near the center of the frame, moving toward the left at 24 kilometers per second. Its strong stellar wind precedes it, compressing and heating the dusty interstellar material and shaping the curved shock front. What set this star in motion? Zeta Oph was likely once a member of a binary star system, its companion star was more massive and hence shorter lived. When the companion exploded as a supernova catastrophically losing mass, Zeta Oph was flung out of the system. About 460 light-years away, Zeta Oph is 65,000 times more luminous than the Sun and would be one of the brighter stars in the sky if it weren't surrounded by obscuring dust. The image spans about 1.5 degrees or 12 light-years at the estimated distance of Zeta Ophiuchi.
Comet Hale-Bopp Over Val Parola Pass (2017-04-09)
Comet Hale-Bopp, the Great Comet of 1997, became much brighter than any surrounding stars. It was seen even over bright city lights. Away from city lights, however, it put on quite a spectacular show. Here Comet Hale-Bopp was photographed above Val Parola Pass in the Dolomite mountains surrounding Cortina d'Ampezzo, Italy. Comet Hale-Bopp's blue ion tail, consisting of ions from the comet's nucleus, is pushed out by the solar wind. The white dust tail is composed of larger particles of dust from the nucleus driven by the pressure of sunlight, that orbit behind the comet. Comet Hale-Bopp (C/1995 O1) remained visible to the unaided eye for 18 months -- longer than any other comet in recorded history. This year marks the 20th anniversary of Comet Hale-Bopp's last trip to the inner Solar System.  The large comet is next expected to return around the year 4385.
Galaxy Cluster Gas Creates Hole in Microwave Background (2017-04-10)
Why would this cluster of galaxy punch a hole in the cosmic microwave background (CMB)? First, the famous CMB was created by cooling gas in the early universe and flies right through most gas and dust in the universe. It is all around us. Large clusters of galaxies have enough gravity to contain very hot gas -- gas hot enough to up-scatter microwave photons into light of significantly higher energy, thereby creating a hole in CMB maps.  This Sunyaev�Zel'dovich (SZ) effect has been used for decades to reveal new information about hot gas in clusters and even to help discover galaxy clusters in a simple yet uniform way. Pictured is the most detailed image yet obtained of the SZ effect, now using both  ALMA to measure the CMB and the Hubble Space Telescope to measure the galaxies in the massive galaxy cluster RX J1347.5-1145.  False-color blue depicts light from the CMB, while almost every yellow object is a galaxy.  The shape of the SZ hole indicates not only that hot gas is present in this galaxy cluster, but also that it is distributed in a surprisingly uneven manner.
Man, Dog, Sun (2017-04-11)
This was supposed to be a shot of trees in front of a setting Sun. Sometimes, though, the unexpected can be photogenic. During some planning shots, a man walking his dog unexpected crossed the ridge. The result was so striking that, after cropping, it became the main shot.  The reason the Sun appears so large is that the image was taken from about a kilometer away through a telephoto lens.  Scattering of blue light by the Earth's atmosphere makes the bottom of the Sun appear slightly more red that the top. Also, if you look closely at the Sun, just above the man's head, a large group of sunspots is visible. The image was taken just last week in Bad Mergentheim, Germany.
Leo Trio (2017-04-12)
This group is popular in the northern spring. Famous as the Leo Triplet, the three magnificent galaxies gather in one field of view. Crowd pleasers when imaged with even modest telescopes, they can be introduced individually as NGC 3628 (left), M66 (bottom right), and M65 (top). All three are large spiral galaxies but they tend to look dissimilar because their galactic disks are tilted at different angles to our line of sight. NGC 3628 is seen edge-on, with obscuring dust lanes cutting across the plane of the galaxy, while the disks of M66 and M65 are both inclined enough to show off their spiral structure.  Gravitational interactions between galaxies in the group have also left telltale signs, including the warped and inflated disk of NGC 3628 and the drawn out spiral arms of M66. This gorgeous view of the region spans about one degree (two full moons) on the sky. The field covers over 500 thousand light-years at the trio's estimated distance of 30 million light-years.
Moons and Jupiter (2017-04-13)
On April 10, a Full Moon and Jupiter shared this telephoto field of view. Both were near opposition, opposite the Sun in Earth's night sky. Captured when a passing cloud bank dimmmed the bright moonlight, the single exposure reveals the familiar face of our fair planet's own large natural satellite, along with a line up of the ruling gas giant's four Galilean moons. Labeled top to bottom, the tiny pinpricks of light above bright Jupiter are Callisto, Europa, Ganymede, and Io. Closer and brighter, our own natural satellite appears to loom large. But Callisto, Ganymede, and Io are physically larger than Earth's Moon, while water world Europa is only slightly smaller.  In fact, of the Solar System's six largest planetary satellites, only Saturn's moon Titan is missing from the scene.
Earth Shadow over Damavand (2017-04-14)
Through crystal clear skies this beautiful panorama follows the curve of planet Earth's shadow rising across the top of the world. The tantalizing twilight view is composed of eight single frames captured from 4,000 meters above sea level at sunset on April 6. Just above the dark grey Earth-shadow boundary lies a fading, pinkish, anti-twilight arch. Also known as the belt of Venus, its reddened and back-scattered sunlight finally merges with the still blue eastern sky. Standing tall near center along the rugged horizon line is the distant sharp peak of Mount Damavand in the snowy Alborz mountains. A feature in Persian mythology and literature, Damavand is a stratovolcano reaching 5,610 meters above sea level, the highest peak in Iran and the Middle East.
Luminous Salar de Uyuni (2017-04-15)
A scene in high contrast this thoughtful night skyscape is a modern composition inspired by M. C. Escher's lithograph Phosphorescent Sea. In it, bright familiar stars of Orion the Hunter and Aldebaran, eye of Taurus the Bull, hang in clear dark skies above a distant horizon. Below, faintly luminous edges trace an otherworldly constellation of patterns in mineral-crusted mud along the Uyuni Salt Flat of southwest Bolivia. The remains of an ancient lake, the Uyuni Salt Flat, Salar de Uyuni, is planet Earth's largest salt flat, located on the Bolivian Altiplano at an altitude of about 3,600 meters. Escher's 1933 lithograph also featured familiar stars in planet Earth's night, framing The Plough or Big Dipper above waves breaking on a more northern shore.
Life-Enabling Plumes above Enceladus (2017-04-16)
Does Enceladus have underground oceans that could support life? The discovery of jets spewing water vapor and ice was detected by the Saturn-orbiting Cassini spacecraft in 2005.  The origin of the water feeding the jets, however, was originally unknown.  Since discovery, evidence has been accumulating that Enceladus has a deep underground sea, warmed by tidal flexing.  Pictured here, the textured surface of Enceladus is visible in the foreground, while rows of plumes rise from ice fractures in the distance.  These jets are made more visible by the Sun angle and the encroaching shadow of night. A recent fly-through has found evidence that a plume -- and so surely the underlying sea -- is rich in molecular hydrogen, a viable food source for microbes that could potentially be living there.
Night Glows (2017-04-18)
What glows in the night? This night, several unusual glows were evident -- some near, but some far. The foreground surf glimmers blue with the light of bioluminescent plankton.  Next out, Earth's atmosphere dims the horizon and provides a few opaque clouds. Farther out, the planet Venus glows bright near the image center. If you slightly avert your eyes, a diagonal beam of light will stand out crossing behind Venus. This band is zodiacal light, sunlight scattered by dust in our Solar System. Much farther away are numerous single bright stars, most closer than 100 light years away. Farthest away, also rising diagonally and making a "V" with the zodiacal light, is the central band of our Milky Way Galaxy. Most of the billions of Milky Way stars and dark clouds are thousands of light years away. The featured image was taken last November on the Iranian coast of Gulf of Oman.
The Red Spider Planetary Nebula (2017-04-19)
Oh what a tangled web a planetary nebula can weave.  The Red Spider Planetary Nebula shows the complex structure that can result when a normal star ejects its outer gases and becomes a white dwarf star. Officially tagged NGC 6537, this two-lobed symmetric planetary nebula houses one of the hottest white dwarfs ever observed, probably as part of a binary star system.  Internal winds emanating from the central stars, visible in the center, have been measured in excess of 1000 kilometers per second. These winds expand the nebula, flow along the nebula's walls, and cause waves of hot gas and dust to collide.  Atoms caught in these colliding shocks radiate light shown in the above representative-color picture by the Hubble Space Telescope.  The Red Spider Nebula lies toward the constellation of the Archer (Sagittarius).  Its distance is not well known but has been estimated by some to be about 4,000 light-years.    Follow APOD on: Facebook,  Google Plus,  Instagram, or Twitter
Asteroid 2014 JO25 (2017-04-20)
A day before its closest approach, asteroid 2014 JO25 was imaged by radar with the 70-meter antenna of NASA's Goldstone Deep Space Communications Complex in California. This grid of 30 radar images, top left to lower right, reveals the two-lobed shape of the asteroid that rotates about once every five hours. Its largest lobe is about 610 meters across. On the list of Potentially Hazardous Asteroids, this space rock made its close approach to our fair planet on April 19, flying safely past at a distance of 1.8 million kilometers. That's over four times the distance from the Earth to the Moon. The asteroid was a faint and fast moving speck visible in backyard telescopes. Asteroid 2014 JO25 was discovered in May 2014 by A. D. Grauer of the Catalina Sky Survey, a project of NASA's Near-Earth Objects Observations Program in collaboration with the University of Arizona.