juliensimon/nasa-apod huggingface dataset:
Cartwheel of Fortune (2006-01-18)

By chance, a collision of two galaxies has created a surprisingly recognizable shape on a cosmic scale - The Cartwheel Galaxy. The Cartwheel is part of a group of galaxies about 400 million light years away in the constellation Sculptor (two smaller galaxies in the group are visible below and left). Its rim is an immense ring-like structure over 100,000 light years in diameter, composed of star forming regions filled with extremely bright, massive stars. When galaxies collide they pass through each other, their individual stars do not come into contact. However, this ring-like shape is the result of gravitational disruption caused by a smaller galaxy passing through a large one, compressing the interstellar gas and dust and causing a star formation wave to move out like a ripple across the surface of a pond. This false-color composite image of the Cartwheel Galaxy is from space-based observatories. The Chandra X-ray Observatory data is in purple, the Galaxy Evolution Explorer ultraviolet view is in blue, the Hubble Space Telescope visible light picture is in green and the Spitzer Space Telescope infrared image is in red.
Orion Nebula: The Hubble View (2006-01-19)

Few cosmic vistas excite the imagination like the Orion Nebula. Also known as M42, the nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1,500 light-years away. The Orion Nebula offers one of the best opportunities to study how stars are born partly because it is the nearest large star-forming region, but also because the nebula's energetic stars have blown away obscuring gas and dust clouds that would otherwise block our view - providing an intimate look at a range of ongoing stages of starbirth and evolution. This detailed image of the Orion Nebula is the sharpest ever, constructed using data from the Hubble Space Telescope's Advanced Camera for Surveys and the European Southern Observatory's La Silla 2.2 meter telescope. The mosaic contains a billion pixels at full resolution and reveals about 3,000 stars. In apparent size, the picture is as large as the Full Moon. At the distance of M42 it spans thirteen light-years.
LL Ori and the Orion Nebula (2006-01-20)

This esthetic close-up of cosmic clouds and stellar winds features LL Orionis, interacting with the Orion Nebula flow. Adrift in Orion's stellar nursery and still in its formative years, variable star LL Orionis produces a wind more energetic than the wind from our own middle-aged Sun. As the fast stellar wind runs into slow moving gas a shock front is formed, analogous to the bow wave of a boat moving through water or a plane traveling at supersonic speed. The small, arcing, graceful structure just above and left of center is LL Ori's cosmic bow shock, measuring about half a light-year across. The slower gas is flowing away from the Orion Nebula's hot central star cluster, the Trapezium, located off the upper left corner of the picture. In three dimensions, LL Ori's wrap-around shock front is shaped like a bowl that appears brightest when viewed along the "bottom" edge. The beautiful picture is part of a large mosaic view of the complex stellar nursery in Orion, filled with a myriad of fluid shapes associated with star formation.
Apollo 12: Self-Portrait (2006-01-21)

In November of 1969, Apollo 12 astronaut-photographer Charles "Pete" Conrad recorded this masterpiece while documenting colleague Alan Bean's lunar soil collection activities on the Oceanus Procellarum. The image is dramatic and stark. The harsh environment of the Moon's Ocean of Storms is echoed in Bean's helmet, a perfectly composed reflection of Conrad and the lunar horizon. Is it art? Works of photojournalists originally intent on recording the human condition on planet Earth, such as Lewis W. Hine's images from New York City in the early 20th century, or Margaret Bourke-White's magazine photography are widely regarded as art. Similarly many documentary astronomy and space images can be appreciated for their artistic and esthetic appeal.
D. rad Bacteria: Candidate Astronauts (2006-01-22)

These bacteria could survive on another planet.  In an Earth lab, Deinococcus radiodurans (D. rad) survive extreme levels of radiation, extreme temperatures, dehydration, and exposure to genotoxic chemicals.  Amazingly, they even have the ability to repair their own  DNA, usually with 48 hours.  Known as an extremophile, bacteria such as  D. rad are of interest to NASA partly because they might be adaptable to help human astronauts survive on other worlds.  A recent map of D. rad's  DNA might allow biologists to augment their survival skills with the ability to produce medicine, clean water, and oxygen.  Already they have been genetically engineered to  help clean up spills of toxic mercury.  Likely one of the oldest surviving life forms, D. rad was discovered by accident in the 1950s when scientists investigating food preservation techniques could not easily kill it.  Pictured above, Deinococcus radiodurans grow quietly in a dish.
The LMC Galaxy in Glowing Gas (2006-01-23)

What goes on inside of a galaxy? To help find out, astronomers from the Magellanic Cloud Emission Line Survey team imaged our neighboring LMC galaxy in spectacular detail and highlighted very specific colors of light emitted by glowing gas. The above mosaic of over 1,500 images of the Large Magellanic Cloud (LMC) is the result -- clicking on the image will bring up an image with much greater detail.  The colors highlighted on the mosaic are light emitted by hydrogen (red), oxygen (green), and sulfur (yellow), while light from individual stars has been subtracted. The mosaic shows what a busy and violent place the inside of the LMC really is. Visible in the above image are many small planetary nebulas pushed out by low mass stars, large emission nebula of ambient interstellar gas set aglow by massive stars, and huge gaseous supernova remnants cast off by massive stars exploding.  The extended connected filaments are mostly connected supernova remnants.  The LMC, a familiar sight to an unaided eye in the southern hemisphere, spans about 15,000 light years and lies only about 180,000 light years distant.
New Horizons Launches to Pluto (2006-01-24)

Destination: Pluto.  The New Horizons spacecraft roared off its launch pad at Cape Canaveral in Florida, USA last week toward adventures in the distant Solar System.   The craft is one of the fastest spaceships ever launched by humans, having passed the Moon only nine hours after launch and is on track to buzz Jupiter in early 2007.  Even traveling over 75,000 kilometers per hour, the New Horizons craft will not arrive at Pluto until 2015.  Pluto is the only remaining planet that has never been visited by a spacecraft or photographed up close.  After Pluto, the robot spaceship will visit one or more Kuiper Belt Objects orbiting the Sun even further out than Pluto.  Pictured, the New Horizons craft launches into space atop a powerful Atlas V rocket.

Image credit: Ben Cooper
The Expanding Light Echoes of SN 1987A (2006-01-25)

Can you find supernova 1987A?  It isn't hard -- it occurred at the center of the expanding bullseye pattern.  Although this stellar detonation was first seen almost two decades ago, light from it continues to bounce off clumps of interstellar dust and be reflected to us today.  These expanding light echoes have been recorded in the above time-lapse movie recorded over four years from the Blanco 4-meter telescope in Chile.  The first image is an image of the SN 1987A region, while the next four images were created by subtracting consecutive images, taken a year apart, and leaving only the difference between the images.  Light echoes can be seen moving out from the position of the supernova.  The SuperMACHO team who recorded the above light echoes around supernova 1987A has also found faint and previously unnoticed light echoes from two other LMC supernovas.  Study of these light echoes has enabled more accurate determinations of the location and date of these two supernova explosions that were first visible hundreds of years ago.
An Unusual Two-Toned Rock on Mars (2006-01-26)

How did this unusual Martian rock form? The atypical two-toned rock, visible in the lower right of the above image, was photographed a few days ago by the robotic Spirit rover currently rolling across Mars.  For now, the environmental processes that created the rock remain a matter of speculation.  Finding unusual rocks is not unusual for Spirit or its twin rover Opportunity, however.  Over the past two years, for example, the rovers have unexpectedly discovered very small gray pebbles dubbed blueberries, and a rock out in the middle of nowhere now thought to be a meteorite.  Having investigated alien terrain and having found clear evidence that part of Mars had a wet past, the Earth-launched Martian rovers are now entering their third spectacular year exploring the red planet.
A New Storm on Saturn (2006-01-27)

Presently at opposition in planet Earth's sky, Saturn is well placed for telescopic observations. On Wednesday two amateur astronomers took full advantage of the situation from Melun, near Paris, France. With a 12 inch diameter telescope and web cam they recorded this sharp image of the ringed gas giant and made an exciting discovery -- a new storm on Saturn. The storm appears as the white spot visible here in Saturn's southern hemisphere (south is toward the top in the picture). In particular, the storm seems to correspond with an outburst of radio noise detected by the Cassini spacecraft. The phenomenon is likely similar to the Dragon Storm recorded by Cassini's instruments early last year. That storm is thought to be analogous to a terrestrial thunderstorm, with radio noise produced in high-voltage lightning discharges.

Image credit: Erick Bondoux,
Jean-Luc Dauvergne
Saturn in the Hive (2006-01-28)

If you can find Saturn in tonight's sky, then you can also find M44, popularly known as the Beehive star cluster. In fact, with a pair of binoculars most casual skygazers should find it fairly easy to zero in on this celestial scene. Saturn is at opposition - opposite the Sun in Earth's sky - so, the bright planet rises in the east at sunset and is visible throughout the night. Near the stationary part of its wandering path through the heavens, Saturn will obligingly linger for a while in the vicinity of M44 in the relatively faint constellation Cancer. Seen here in a photograph from January 25, Saturn (lower right) is strongly overexposed with the stars of M44 swarming above and to the left.  The picture approximately corresponds to the view when looking through a typical pair of binoculars. Saturn is about 64 light-minutes from our fair planet while M44, one of the closest star clusters, is around 600 light-years away.

Image credit: Jimmy Westlake
(Colorado
Mountain College)
Volcano and Aurora in Iceland (2006-01-29)

Sometimes both heaven and Earth erupt.  In Iceland in 1991, the volcano Hekla erupted at the same time that auroras were visible overhead.  Hekla, one of the most  famous volcanoes in the world, has erupted at least 20 times over the past millennium, sometimes causing great destruction.  The last eruption occurred only six years ago but caused only minor damage.  The green auroral band occurred fortuitously about 100 kilometers above the erupting  lava.  Is Earth the Solar System's only planet with both auroras and volcanos?
NGC 1999: South of Orion (2006-01-30)

South of the large star-forming region known as the Orion Nebula, lies bright blue reflection nebula NGC 1999. The nebula is marked with a dark inverted T-shape at the lower left in a broad cosmic vista that spans over 10 light-years. The dark shape is a dense gas and dust cloud, or Bok globule, seen in silhouette against the bright nebula, and likely a site of future star formation. At the edge of the Orion molecular cloud complex some 1,500 light-years distant, NGC 1999's illumination is provided by the embedded variable star V380 Orionis. The region abounds with energetic young stars producing jets and outflows that create luminous shock waves, including HH (Herbig-Haro) 1 and 2 just below and left of NGC 1999, and the apparent cascade of reddish arcs and bow shocks beginning at the upper right. The stellar jets and outflows push through the surrounding material at speeds of hundreds of kilometers per second.

Image credit: Robert Gendler
Huygens on Titan Illustrated (2006-01-31)

If you could stand on Titan, what might you see?  About one year ago the robotic Huygens probe landed on the enigmatic moon of Saturn and sent back the first ever images from beneath Titan's thick cloud layers.   From the images sent back, an artist's impression of Huygens on Titan's surface has been reconstructed.  In the foreground of the above image sits the car-sized lander that sent back images for more than 90 minutes before running out of battery power.  The parachute that slowed Huygen's re-entry is seen in the background, attached to the lander by strong cords.  Strange light smooth stones possibly containing water-ice are visible surrounding the landing craft.  Analyses of Huygen's images and data shows that Titan's surface today has intriguing similarities to the surface of the early Earth.
Venus Just After Sunset (2006-02-01)

Is that Venus or an airplane?  A common ponderable for sky enthusiasts is deciding if that bright spot near the horizon is the planet Venus.  Usually, an airplane will show itself by moving significantly in a few moments.  Venus will set only slowly as the Earth turns.  Still, the identification would be easier if Venus did not keep shifting its position each night.  Pictured above, Venus was captured 38 different nights during 2005 and 2006 over Bursa, Turkey, when Earth's sister planet appeared exclusively in the evening sky.  The average spacing of the images was about five days, while the images were always taken with the Sun about 7 degrees below the horizon.  Venus' orbit around the Sun will now confine it to Earth's morning sky until October 2006.

Image credit: Tun� Tezel
Thor's Helmet in H-Alpha (2006-02-02)

Near picture center, the helmet-shaped structure with wing-like appendages is popularly called Thor's Helmet. Cataloged as NGC 2359, the striking nebula is located about 15,000 light-years away in the constellation Canis Major. The helmet is actually more like a cosmic bubble, blown as the wind from the bright, massive star near the bubble's center sweeps through the surrounding molecular cloud. Known as a Wolf-Rayet star, the energetic star is a blue giant thought to be in a brief, pre-supernova stage of evolution. The remarkable color composite combines broad and narrow band images - including a deep exposure recorded with an H-alpha filter. The H-alpha image traces the light from the region's glowing atomic hydrogen gas. Heroically sized even for a Norse god, this Thor's Helmet is about 30 light-years across.

Image credit: Don Goldman
Cosmic Tornado HH49/50 (2006-02-03)

Light-years in length, this cosmic tornado is actually a powerful jet cataloged as HH (Herbig-Haro) 49/50 blasting down from the top of a Spitzer Space Telescope view. Though such energetic outflows are well known to be associated with the formation of young stars, the exact cause of the spiraling structures apparent in this case is still mysterious. The embryonic star responsible for the 100-kilometer per second jet is located just off the top of the picture, while the bright star seen near the tip of the jet may just by chance lie along the line of sight. In the false-color infrared image, the tornado glows with infrared light generated as the outflow heats surrounding dust clouds. The color coding shows a trend from red to blue hues at the tornado's tip indicating a systematic increase in emission at shorter wavelengths. The trend is thought to indicate an increase in molecular excitation closer to where the head of the jet is impacting interstellar gas. HH49/50 is about 450 light-years distant, located in the Chamaeleon I molecular cloud.
Shadow Set (2006-02-04)

A nearly full Moon and planet Earth's shadow set together in this scene captured on January 13th from snowy Mt. Jelm, home of the Wyoming Infrared Observatory. For early morning risers (and late to bed astronomers), shadow set in the western sky is a daily apparition whose subtle beauty is often overlooked in favor of the more colorful eastern horizon. Extending through the dense atmosphere, Earth's setting shadow is seen in this picture as a dark blue band along the distant horizon, bounded above by a pinkish glow or antitwilight arch. Known as the Belt of Venus, the arch's lovely color is due to backscattering of reddened light from the rising Sun. The setting Moon's light is also reddened by the long sight-line through the atmosphere.
A Sun Pillar in Red and Violet (2006-02-05)

Sometimes the unknown is beautiful.  In 2000 February near Lake Tahoe, Nevada, two amateur photographers noticed an unusual red column of light rise mysteriously from a setting sun.  During the next few minutes, they were able to capture the pillar and a  photogenic sunset on film.  Pictured above, the red column is seen above a serene Lake Tahoe and snow-capped mountains across from Lake Tahoe-Nevada State Park.  The mysterious column, they learned later, is a Sun Pillar, a phenomenon where sunlight reflects off of distant falling ice crystals.

Image credit: Jim Kirkpatrick & Brigitte Heiter-Kirkpatrick
The N44 Superbubble (2006-02-06)

What created this gigantic hole?  The vast emission nebula N44 in our neighboring galaxy the Large Magellanic Cloud has a large, 250 light-year hole and astronomers are trying to figure out why.  One possibility is particle winds expelled by massive stars in the bubble's interior that are pushing out the glowing gas.  This answer has been recently found to be inconsistent with measured wind velocities, however.  Another possibility is that the expanding shells of old supernovas have sculpted the unusual space cavern.   An unexpected clue of hot X-ray emitting gas was recently been detected escaping the N44 superbubble.  The above image, here digitally sharpened, was taken in three very specific colors by the huge 8-meter Gemini South Telescope on Cerro Pachon in Chile.

Image credit: Gemini Obs.
UB 313: Larger than Pluto (2006-02-07)

What do you call an outer Solar System object that is larger than Pluto?  Nobody is yet sure.  The question arose recently when 2003 UB313, an object currently twice as far out as Pluto and not in the plane with the rest of the planets, was verified recently to be 30 percent wider than Pluto.  UB313's size was measured by a noting its distance from the Sun and how much infrared light it emits.  Previous size estimates were based only on visible light and greatly affected by how reflective the object is.  Whether 2003 UB313 is officially declared a planet will be answered shortly by the International Astronomical Union.  In the above picture, a scientific artist has imagined UB313 in its distant orbit around the Sun coupled with a hypothetical moon.

Image credit: Thierry Lombry
The Great Basin on Tethys (2006-02-08)

Some moons wouldn't survive the collision.  Tethys, one of Saturn's larger moons at about 1000 kilometers in diameter, survived the collision, but sports today the expansive impact crater Odysseus.  Sometimes called the Great Basin, Odysseus occurs on the leading hemisphere of Tethys and shows its great age by the relative amount of smaller craters that occur inside its towering walls.  The density of Tethys is similar to water-ice.  The above digitally enhanced image was captured late last year by the robot Cassini spacecraft  in orbit around Saturn as it swooped past the giant ice ball.
NGC 1309 and Friends (2006-02-09)

A gorgeous spiral galaxy some 100 million light-years distant, NGC 1309 lies on the banks of the constellation Eridanus. NGC 1309 spans about 30,000 light-years, one third the size of our larger Milky Way galaxy. Bluish clusters of young stars and dust lanes are seen to trace out NGC 1309's spiral arms as they wind around an older yellowish star population at its core. Not just another pretty face-on spiral galaxy, observations of NGC 1309's recent supernova and cepheid stars contribute to the calibration of the expansion of the Universe. Still, after you get over this beautiful galaxy's grand design, check out the array of more distant background galaxies also recorded in the sharp Hubble Space Telescope view.
M8: The Lagoon Nebula (2006-02-10)

This beautiful cosmic cloud is a popular stop on telescopic tours of the constellation Sagittarius. Eighteenth century cosmic tourist Charles Messier cataloged the bright nebula as M8, while modern day astronomers recognize the Lagoon Nebula as an active stellar nursery about 5,000 light-years distant, in the direction of the center of our Milky Way Galaxy. Striking details can be traced through this remarkable picture, processed to reveal the Lagoon's range of filaments of glowing hydrogen gas and dark dust clouds along with the brighter, turbulent hourglass region at the upper right. The view is a color composite of narrow and broad band images recorded under dark skies in northwestern Arizona. At the Lagoon's estimated distance, the picture spans about 30 light-years.

Image credit: Processing: Tom Davis,
Acquisition: Jim Misti
Plato and the Lunar Alps (2006-02-11)

The dark-floored, 95 kilometer wide crater Plato (top) and sunlit peaks of the lunar Alps are highlighted in this sharp digital mosaic of the Moon's surface. While the Alps of planet Earth were uplifted over millions of years as continental plates slowly collided, the lunar Alps were likely formed by a sudden collision that created the giant impact basin known as the Mare Imbrium (Sea of Rains). The mare's generally smooth, lava-flooded floor is seen extending to the left. The prominent straight feature cutting through the mountain range (lower right) is the lunar Alpine Valley, about 160 kilometers long and up to 10 kilometers wide. Of course, the large, bright alpine mountain near bottom center is named Mont Blanc and reaches over 3 kilometers above the lunar surface. Lacking an atmosphere, not to mention snow, the lunar Alps are probably not an ideal site for the Winter Olympic Games. Still, a 150 pound skier would weigh a mere 25 pounds on the Moon.

Image credit: Alan Friedman
Phoebe: Comet Moon of Saturn (2006-02-12)

Was Saturn's moon Phoebe once a comet?  Images from the robotic Cassini spacecraft taken two years ago when entering the neighborhood of Saturn indicate that Phoebe may have originated in the outer Solar System.  Phoebe's irregular surface, retrograde orbit, unusually dark surface, assortment of large and small craters, and low average density appear consistent with the hypothesis that Phoebe was once part of the Kuiper belt of icy comets beyond Neptune before being captured by Saturn.  Visible in the above image of Phoebe are craters, streaks, and layered deposits of light and dark material.  The image was taken from around 30,000 kilometers out from this 200-kilometer diameter moon. Two weeks after taking the above image, Cassini fired its engines to decelerate into orbit around Saturn.
The N44 Emission Nebula (2006-02-13)

N44 is one of the largest and most intricate nebulas in this part of the universe.  Located in our galactic neighbor the Large Magellanic Cloud, N44 houses numerous massive bright stars, lengthy lanes of dark dust, and vast clouds of  hydrogen gas that glows red.  The red color of the N44 emission nebula comes from pervasive hydrogen atoms re-acquiring electrons that were knocked away by energetic light from massive stars.  The central stars also appear to have somehow created the huge superbubble visible in the lower left.  N44, pictured above, spans about 1,000 light years and lies about 170,000 light years distant.

Image credit: WFI, 
MPG/ESO 2.2-m Telescope, 
La Silla,
ESO