omnianasa/nasa-apod-metadata huggingface dataset:
Starry Night Scavenger Hunt (2010-06-15)
Did you know that Van Gogh's painting Starry Night includes Comet Hale-Bopp? Hopefully not, because it doesn't. But the above image does.  Although today's featured picture may appear at first glance to be a faithful digital reproduction of the original Starry Night, actually it is a modern rendition meant not only to honor one of the most famous paintings of the second millennium, but to act as a scavenger hunt. Can you find, in the above image, a comet, a spiral galaxy, an open star cluster, and a supernova remnant?  Too easy? OK, then find, the rings of Supernova 1987A, NGC 2392, the Crab Nebula, Thor's Helmet, the Cartwheel Galaxy, and the Ant Nebula. Still too easy? Then please identify any more hidden images not mentioned here -- and there are several -- on APOD's main discussion board: Starship Asterisk.  Finally, the collagist has graciously hidden APOD's 10th anniversary Vermeer photomontage to help honor APOD on its 15th anniversary tomorrow.
APOD is 15 Years Old Today (2010-06-16)
Welcome to the quindecennial year of the Astronomy Picture of the Day! Perhaps a source of web consistency for some, APOD is still here.  As during each of the 15 years of selecting images, writing text, and editing the APOD web pages, the occasionally industrious Robert Nemiroff (left) and frequently persistent Jerry Bonnell (right) are pictured above plotting to highlight yet another unsuspecting image of our cosmos. Although the above image may appear similar to the whimsical Vermeer composite that ran on APOD's fifth anniversary, a perceptive eye might catch that this year it has been digitally re-pixelated using many of the over 5,000 APOD images that have appeared over APOD's tenure.  (Can you find any notable APOD images?) Once again, we at APOD would like to offer a sincere thank you to our readership for continued interest, support, and many gracious communications.
Comet McNaught Passes NGC 1245 (2010-06-17)
Of the many comets named for discoverer Robert McNaught, the one cataloged as C/2009 R1 is gracing dawn skies for northern hemisphere observers this month.  Seen here on June 13th from southern New Mexico, this Comet McNaught's long ion tail sweeps across the telescopic field of view (a negative image is inset). Remarkably, the ion tail easily stretches past background star cluster NGC 1245 (upper left) in the constellation Perseus, about 1.5 degrees from the comet's lovely greenish head or coma. The coma also sports a short, stubby, dust tail. Of course, the comet and background stars move at different rates through planet Earth's skies. But a digital processing of many short exposures allowed frames of comet and stars to be separated, registered, and recombined in the final image. To see the comet separate from the background stars, just slide your cursor over the image. The recombined frames show off both the rich star field and faint details of the comet. Easy to spot in binoculars for now, McNaught will sink into the twilight along the eastern horizon in the coming days as it heads toward perihelion (closest approach to the Sun) on July 2.
Star Trails and Tajinastes (2010-06-18)
What bizarre planet do these alien creatures inhabit? It's only planet Earth, of course. In this well-composed scene, the sky is filled with star trails around the north celestial pole. A reflection of the Earth's daily rotation on its axis, star trails are familiar to photographers who fix their camera to a tripod and make long exposures of the night sky. But the imposing forms gazing skyward probably look strange to many denizens of Earth. Found on the Canary Island of Tenerife, they are red tajinastes, rare flowering plants that grow to a height of up to 3 meters. Hidden among the rocks of the volcanic terrain, tajinastes bloom in spring and early summer and then die after their seeds mature. On the distant horizon, below and left of the celestial pole, lies the Teide volcano.
Stereo Itokawa (2010-06-19)
Get out your red/blue glasses and float next to asteroid Itokawa, a diminutive world of the solar system only half a kilometer across. Boulders strewn across its rough surface and the lack of craters indicate that this asteroid is a rubble pile, formed as smaller pieces collected and were kept together by gravity. The stereo view was constructed from images made by the Hayabusa spacecraft when it encountered the asteroid in 2005. After a long journey, the spacecraft re-entered the atmosphere on June 13 over Australia, successfully parachuting a capsule to Earth. Hayabusa's capsule could contain a small sample of material from rubble pile asteroid Itokawa.   Ponder: Can you guess the result to this simple experiment?
Abell 2218: A Galaxy Cluster Lens (2010-06-20)
What are those strange filaments?  Background galaxies. Gravity can bend light, allowing huge clusters of galaxies to act as telescopes, and distorting images of background galaxies into elongated strands. Almost all of the bright objects in this Hubble Space Telescope image are galaxies in the cluster known as Abell 2218. The cluster is so massive and so compact that its gravity bends and focuses the light from galaxies that lie behind it. As a result, multiple images of these background galaxies are distorted into long faint arcs -- a simple lensing effect analogous to viewing distant street lamps through a glass of wine. The cluster of galaxies Abell 2218 is itself about three billion light-years away in the northern constellation of the Dragon (Draco). The power of this massive cluster telescope has allowed astronomers to detect a galaxy at the distant redshift of 5.58.
Sunrise Solstice at Stonehenge (2010-06-21)
Today the Sun reaches its northernmost point in planet Earth's sky.  Called a solstice, the date traditionally marks a change of seasons -- from spring to summer in Earth's Northern Hemisphere and from fall to winter in Earth's Southern Hemisphere.  The above image was taken during the week of the 2008 summer solstice at Stonehenge in United Kingdom, and captures a picturesque sunrise involving fog, trees, clouds, stones placed about 4,500 years ago, and a 5 billion year old large glowing orb. Even given the precession of the Earth's rotational axis over the millennia, the Sun continues to rise over Stonehenge in an astronomically significant way.
Islands of Four Mountains from Above (2010-06-22)
Our Earth is covered by volcanoes. Volcanoes are breaks in the Earth's cool surface where hot liquid rock from the interior comes out -- sometimes suddenly. In the above image from the ASTER camera aboard NASA's orbiting Terra satellite, snow-capped volcanoes are seen from overhead that compose the picturesque Islands of the Four Mountains in the Aleutian Islands, Alaska, USA. The islands contain restless Mt. Cleveland, an active volcano currently being watched to see if it emits an ash cloud that could affect air travel over parts of North America. A close look at Mt. Cleveland, seen near the image center, shows red vegetation (false color), a white snow-covered peak, a light plume of gas and ash, and dark lanes where ash and debris fell or flowed.  Millions of volcanoes have likely been active over the turbulent history of the Earth's surface, while about 20 volcanoes are erupting even today, at any given time.
Sunset from the International Space Station (2010-06-23)
What are these strange color bands being seen from the International Space Station? The Sun setting through Earth's atmosphere.  Pictured above, a sunset captured last month by the ISS's Expedition 23 crew shows in vivid detail many layers of the Earth's thin atmosphere. Part of the Earth experiencing night crosses the bottom of the image. Above that, appearing in deep orange and yellow, is the Earth's troposphere, which contains 80 percent of the atmosphere by mass and almost all of the clouds in the sky. Above the troposphere, seen as a light blue band with white clouds, is the stratosphere, part of the Earth's atmosphere where airplanes fly and some hardy bacteria float. Above the stratosphere, visible as a darker blue bands, are higher and thinner atmospheric levels that gradually fade away into the cold dark  vacuum of outer space. Sunset is not an uncommon sight for occupants of the International Space Station, because it can be seen as many as 16 times a day.
The Dark Tower in Scorpius (2010-06-24)
In silhouette against a crowded star field toward the constellation Scorpius, this dusty cosmic cloud evokes for some the image of an ominous dark tower. In fact, clumps of dust and molecular gas collapsing to form stars may well lurk within the dark nebula, a structure that spans almost 40 light-years across the gorgeous telescopic view. Known as a cometary globule, the swept-back cloud, extending from the lower left to the head (top of the tower) right and above center, is shaped by intense ultraviolet radiation from the OB association of very hot stars in NGC 6231, off the right edge of the scene. That energetic ultraviolet light also powers the globule's bordering reddish glow of hydrogen gas. Hot stars embedded in the dust can be seen as bluish reflection nebulae. This dark tower, NGC 6231, and associated nebulae are about 5,000 light-years away.
The Starry Night of Alamut (2010-06-25)
A meteor's streak and the arc of the Milky Way hang over the imposing mountain fortress of Alamut in this starry scene. Found in the central Alborz Mountains of Iran, Alamut Castle was built into the rock in the 9th century. The name means Eagle's Nest. Home of the legendary Assassins featured in the adventure movie Prince of Persia, Alamut was also historically a center for libraries and education. For a time, it was the residence of important 13th century Persian scholar and astronomer Nasir al-Din al-Tusi. To identify the stars in a night sky Tusi certainly pondered, just slide your cursor over the image. Highlights include bright white stars Deneb (in Cygnus), Vega, and Altair, nebulae near the Galactic Center, and the dark obscuring dust clouds of the Milky Way also known as the Great Rift. Lights at the lower right are from small villages and the capital Tehran, over 100 kilometers away to the southwest.
Young Star Cluster Westerlund 2 (2010-06-26)
Dusty stellar nursery RCW 49 surrounds young star cluster Westerlund 2 in this remarkable composite skyscape from beyond the visible spectrum of light. Infrared data from the Spitzer Space Telescope is shown in black and white, complementing the Chandra X-ray image data (in false color) of the hot energetic stars within the cluster's central region. Looking toward the grand southern constellation Centaurus, both views reveal stars and structures hidden from optical telescopes by obscuring dust. Westerlund 2 itself is a mere 2 million years old or less, and contains some of our galaxy's most luminous, massive and therefore short-lived stars. The infrared signatures of proto-planetary disks have also been identified in the intense star forming region. At the cluster's estimated distance of 20,000 light-years, the square marking the Chandra field of view would be about 50 light-years on a side.   Curious about the Universe?: Download a free online astronomy lecture.
All the Colors of the Sun (2010-06-27)
It is still not known why the Sun's light is missing some colors. Shown above are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device.  The above spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our white-appearing Sun emits light of nearly every color, it does indeed appear brightest in yellow-green light.  The dark patches in the above spectrum arise from gas at or above the Sun's surface absorbing sunlight emitted below.  Since different types of gas absorb different colors of light, it is possible to determine what gasses compose the Sun.  Helium, for example, was first discovered in 1870 on a solar spectrum and only later found here on Earth.  Today, the majority of spectral absorption lines have been identified - but not all.
A Partial Lunar Eclipse (2010-06-28)
What's happened to the Moon? This past weekend, once again, part of the Moon moved through the Earth's shadow. This happens about once or twice a year, on the average, but not each month since the Moon's orbit around the Earth is slightly tilted. Pictured above, the face of a full moon is partly blocked by Earth's clouds, and partly darkened on the upper right by Earth's umbral shadow. Clouds permitting, the partial lunar eclipse was visible from the half of the Earth facing the Moon at the time of the eclipse, which included much of Earth's Pacific Rim.  On July 11, a total eclipse of the Sun will be visible in a thin swath of Earth crossing the southern Pacific Ocean.
Trees, Sky, Galactic Eye (2010-06-29)
Is beauty in the eye of this beholder? Earlier this month, over R�union Island in the Indian Ocean, a playful photographer with an eye for the sky took eight images and composed the above intriguing picture. The full fisheye frame shows everything above the horizon, including a lamp-illuminated landscape around the edges, and the zenith of the sky directly overhead. The image, however, may be more than beautiful -- it may also be a scavenger hunt. Can you find the photographer's tent, the slope of a volcano (active Piton de la Fournaise), a picturesque shoreline, and the lights of the nearby town (Saint Philippe)? One remarkable feature of the above image is that its center contains the very center of our Milky Way Galaxy.
Fast Gas Bullet from Cosmic Blast N49 (2010-06-30)
What is that strange blue blob on the far right? No one is sure, but it might be a speeding remnant of a powerful supernova that was unexpectedly lopsided. Scattered debris from supernova explosion N49 lights up the sky in this gorgeous composited image based on data from the Chandra and Hubble Space Telescopes. Glowing visible filaments, shown in yellow, and X-ray hot gas, shown in blue, span about 30 light-years in our neighboring galaxy, the Large Magellanic Cloud. Light from the original exploding star reached Earth thousands of years ago, but N49 also marks the location of another energetic outburst -- an extremely intense blast of gamma-rays detected by satellites about 30 years ago on 1979 March 5. The source of the March 5th Event is now attributed to a magnetar - a highly magnetized, spinning neutron star also born in the ancient stellar explosion which created supernova remnant N49. The magnetar, visible near the top of the image, hurtles through the supernova debris cloud at over 70 thousand kilometers per hour. The blue blob on the far right, however, might have been expelled asymmetrically just as a massive star was exploding. If so, it now appears to be moving over 7 million kilometers per hour.
Above Aurora Australis (2010-07-01)
On May 29, looking southward from a vantage point about 350 kilometers above the southern Indian Ocean, astronauts onboard the International Space Station watched this enormous, green ribbon shimmering below. Known as aurora australis or southern lights, the shifting, luminous bands are commonly seen at high northern latitudes as well, there known as the aurora borealis or northern lights. North or south their cause is the same though, as energetic charged particles from the magnetosphere pile into the atmosphere near the Earth's poles. To produce the characteristic greenish glow, the energetic particles excite oxygen atoms at altitudes of 100 kilometers or more. Aurora on May 29 were likely triggered by the interaction of the magnetosphere with a coronal mass ejection erupting from the Sun on May 24.   Join Starship Asterisk: Discuss APODs, see the lastest space images, and browse the latest astronomy stories.
Galaxies on a String (2010-07-02)
Galaxies NGC 5216 (top) and NGC 5218 really do look like they are connected by a string. Of course, that string is a cosmic trail of gas, dust, and stars about 22,000 light-years long. Also known as Keenan's system (for its discoverer) and Arp 104, the interacting galaxy pair is some 17 million light-years away in the constellation Ursa Major. The debris trail that joins them, along with NGC 5218's comma-shaped extension and the distorted arms of NGC 5216, are a consequence of mutual gravitational tides. The tides disrupt the galaxies as they repeatedly swing close to one another. Drawn out over billions of years, the encounters will likely result in their merger into a single galaxy of stars. Such spectacular galactic mergers are now understood to be a normal part of the evolution of galaxies, including our own Milky Way.
A Giant Planet for Beta Pic (2010-07-03)
A mere 50 light-years away, young star Beta Pictoris became one of the most important stars in the sky in the early 1980s. Satellite and ground-based telescopic observations revealed the presence of a surrounding outer, dusty, debris disk and an inner clear zone about the size of our solar system -- strong evidence for the formation of planets. Infrared observations from European Southern Observatory telescopes subsequently detected a source in the clear zone, now confirmed as a giant planet orbiting Beta Pic. The confirmation comes as the planet is detected at two different positions in its orbit. Designated Beta Pictoris b, the giant planet must have formed rapidly as Beta Pic itself is only 8 to 20 million years old. With an orbital period estimated between 17 and 44 years, Beta Pictoris b could lie near the orbit of Saturn if found in our solar system, making it the closest planet to its parent star directly imaged ... so far.
Companion of a Young, Sun-like Star Confirmed (2010-07-04)
The first direct image of an extrasolar planet orbiting a star similar to our Sun has been confirmed. Located just 500 light-years away toward the constellation Scorpius, the parent star, cataloged as 1RXS J160929.1-210524, is only slightly less massive and a little cooler than the Sun. The star is, however, much younger, a few million years old compared to the middle-aged Sun's 5 billion years. This sharp infrared image shows the young star's planetary companion positioned above and left of center. The planet is estimated to have a mass about 8 times the mass of Jupiter, and orbit a whopping 330 times the Earth-Sun distance from its parent star. The young planetary companion is still hot and relatively bright in infrared light, likely due to the heat generated during its formation by gravitational contraction. In fact, such newborn planets are easier to detect before they age and cool and become much more faint. The discovery image, shown above, was taken in 2008 but confirmed only recently by noting that the planet stayed with its parent star as background stars slightly shifted over time.
The Milky Way Over Pulpit Rock (2010-07-05)
Can a picture of the sky be relaxing? A candidate for such a picture might be this image taken only last month from Cape Schank, Victoria, Australia. The frame is highlighted by a dreamlike lagoon, two galaxies, and tens of thousands of stars. The rock cropping on the left may appear from this angle like a human head, but the more famous rock structure is on the far right and known as Pulpit Rock.  Across the top of the image runs a distant stream of bright stars and dark dust that is part of the disk of our spiral Milky Way Galaxy.     On the right, just above Pulpit Rock, is the Milky Way's small neighboring galaxy the Small Magellanic Cloud (SMC). The bright white object just to the left of the SMC is a globular cluster of stars in the Milky Way known as 47 Tucana.    Best Space Images: APOD Editor to Speak at AstroFest Penn State this Friday Night
HCG 87: A Small Group of Galaxies (2010-07-06)
Sometimes galaxies form groups. For example, our own Milky Way Galaxy is part of the Local Group of Galaxies.  Small, compact groups, like Hickson Compact Group 87 (HCG 87) shown above, are interesting partly because they slowly self-destruct.  Indeed, the galaxies of HCG 87 are gravitationally stretching each other during their 100-million year orbits around a common center.  The pulling creates colliding gas that causes bright bursts of star formation and feeds matter into their active galaxy centers.  HCG 87 is composed of a large edge-on spiral galaxy visible on the lower left, an elliptical galaxy visible on the lower right, and a spiral galaxy visible near the top.  The small spiral near the center might be far in the distance.  Several stars from our Galaxy are also visible in the foreground.  The above picture was taken in 1999 July by the Hubble Space Telescope's Wide Field Planetary Camera 2.  Studying groups like HCG 87 allows insight into how all galaxies form and evolve.
Concept Plane: Supersonic Green Machine (2010-07-07)
What will passenger airplanes be like in the future? To help brain storm desirable and workable attributes, NASA sponsors design competitions. Shown here is an artist's depiction of a concept plane that has been recently suggested. This futuristic plane would be expected to achieve supersonic speeds, possibly surpassing the speeds of the supersonic transport planes that ran commercially in the late twentieth century. In terms of noise reduction, the future aircraft has been drawn featuring an inverted V wing stretched over its engines. The structure is intended to reduce the sound from annoying sonic booms. Additionally, future airplanes would aim to have relatively little impact on our environment, including green limits on pollution and fuel consumption. Aircraft utilizing similar design concepts might well become operational by the 2030s.
Dim World, Dark Nebula (2010-07-08)
Dim, distant, dwarf planet Pluto can be hard to spot, especially in recent months as it wanders through the crowded starfields of Sagittarius and the central Milky Way. But fortunately for backyard Pluto hunters, it crossed in front of a dark nebula in early July. The diminutive world is marked with two short lines near the center of this skyscape recorded from New Mexico Skies on July 5. Pluto stands out only because obscuring dark nebula Barnard 92 (B92) blocks the background of the Milky Way's congeries of faint, innumerable stars. Another of astronomer E. E. Barnard's cataloged dark markings on the sky, B93, is easy to pick out just left of B92. Prominent at the lower left is open star cluster NGC 6603. In fact, Pluto, dark nebulae, and star cluster all lie within a portion of M24, also known as the Sagittarius Star Cloud, filling most of the frame.
Microwave Milky Way (2010-07-09)
Seen from our edge-on perspective, the Milky Way Galaxy sprawls across the middle of this false-color, all sky view. The expansive microwave map is based on 1 year's worth of data from instruments onboard the sky-surveying Planck spacecraft. Remarkably, the bright stripe of gas and dust clouds along the galactic plane and the galaxy's enormous arcing structures seen at microwave energies are hundreds or thousands of light-years away, while the mottled regions at the top and bottom represent the Cosmic Microwave Background (CMB) radiation, some 13.7 billion light-years distant. Left over from the Big Bang, fluctuations in the CMB reflect the origins of structure in the evolving universe. Analyzing the microwave data, Planck scientists plan to separate the contributions of the Milky Way and CMB radiation. The work will ferret out the characteristics of the CMB across the entire sky and glean information about the make up of our Milky Way Galaxy.