omnianasa/nasa-apod-metadata huggingface dataset:
Polar Ring Galaxy NGC 2685 (2007-02-16)
NGC 2685 is a confirmed polar ring galaxy - a rare type of galaxy with stars, gas and dust orbiting in rings perpendicular to the plane of a flat galactic disk. The bizarre configuration could be caused by the chance capture of material from another galaxy by a disk galaxy, with the captured debris strung out in a rotating ring. Still, observed properties of NGC 2685 suggest that the rotating ring structure is remarkably old and stable. In this fascinating view of the peculiar system also known as Arp 336 or the Helix galaxy, the strange, perpendicular rings are easy to trace as they pass in front of the galactic disk, along with other disturbed outer structures. NGC 2685 is about 50,000 light-years across and 40 million light-years away in the constellation Ursa Major.
Stereo Eros (2007-02-17)
Get out your red/blue glasses and float next to asteroid 433 Eros, now over 220 million kilometers away! Orbiting the Sun once every 1.8 earth-years, asteroid Eros is a diminutive 40 x 14 x 14 kilometer world of undulating horizons, craters, boulders and valleys. Its unsettling scale and bizarre shape are emphasized in this picture - a mosaic of images from the NEAR Shoemaker spacecraft processed to yield a stereo anaglyphic view.  Along with dramatic chiaroscuro, NEAR's 3-D imaging provided important measurements of the asteroid's landforms and structures, and clues to the origin of this city-sized chunk of solar system. The smallest features visible here are about 30 meters across. After spending a year in orbit around Eros, the historic Near Shoemaker spacecraft made the first ever landing on an asteroid's surface February 12, 2001.
M16: Pillars of Creation (2007-02-18)
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 imaged recently by the orbiting Chandra X-ray Observatory, and it was found that most EGGS are not strong emitters of X-rays.
Nova Over Iran (2007-02-19)
A bright new nova is being studied by astronomers.  The officially dubbed Nova Scorpii 2007 has become so bright in recent days that it is now visible to the unaided eye.   Adventurous early morning sky enthusiasts should look in dark skies toward the constellation of the Scorpion, just below Jupiter and Antares.  The above image may help as a sky chart.   A nova this bright occurs only every few years.  Novas are caused by thermonuclear explosions casting off the outer layers of a white dwarf star.   Pictured above on Friday, the nova was being studied through a small telescope as it appeared over the Varzaneh Desert in Isfahan, Iran. The nova will likely fade but remain visible with binoculars for at least a few more days.
White Ridges on Mars (2007-02-20)
What created these white ridges on Mars?  The images showing the white ridges, including some of the highest resolution images ever taken from Martian orbit, were recorded last year by the Mars Reconnaissance Orbiter (MRO). A current leading hypothesis is that the white ridges formed as water flowed through underground cracks and bleached and hardened the edges of surrounding rocks.  Over millions of years, surface winds eroded the darker rock leaving the raised white ridges.   Such water-created light-colored markings are well known here on Earth.  The hypothesis is particularly interesting as underground water could have helped to support microbial life on the red world. The above image resolves surface features as small as one meter across in Candor Chasma region of huge Valles Marineris on Mars.
Mira Over Germany (2007-02-21)
What's that new star in the sky?  The star might appear new, but it's actually just the variable star Mira near its brightest.  Rolling your cursor over the above vertically compressed image will identify the unusual star Mira, a star that can change from practical invisibility to one of the brighter stars on the sky over the course of a year. Pictured above a castle in Stuttgart, Germany, last week, red giant star Mira appeared near its maximum brightness of magnitude 2. Although similar in mass to our Sun, Mira tenuous and cool atmosphere could extend out past the orbit of Mars, and achieve a luminosity over 10,000 times greater than our Sun. Mira is near the end of its life and its variability is somewhat erratic.  Details of Mira's variability are still being researched, but the reason for Mira's pulsations are thought related to periodic changes in the thickness of parts of Mira's atmosphere.  Recent high resolution images show that Mira is not even round.  Mira lies 420 light years distant toward the constellation of the Monster Whale (Cetus). Mira will fade over the next 200 days, but climb back to naked-eye visibility early next year.
Mystery Over Australia (2007-02-22)
Place your cursor on this stunning view through dark skies over western Australia to highlight wonders of the southern Milky Way -- including the famous Southern Cross, the dark Coal Sack Nebula, and bright reddish emission regions surrounding massive star Eta Carinae. Recorded Tuesday at about 2 am, the thirty minute long color film exposure also captured a bright but mysterious object that moved slowly across the sky for over an hour. Widely seen, the object began as a small point and expanded as it tracked toward the North (left), resulting in a comet-like appearance in this picture. What was it? Reports are now identifying the mystery glow with a plume from the explosion of a malfunctioned Russian rocket stage partially filled with fuel. The rocket stage was marooned in Earth orbit after a failed communication satellite launch almost a year ago on February 28, 2006. A substantial amount of debris from the breakup can be tracked.
Dust and the Helix Nebula (2007-02-23)
Dust makes this cosmic eye look red. The eerie Spitzer Space Telescope image shows infrared radiation from the well-studied Helix Nebula (NGC 7293) a mere 700 light-years away in the constellation Aquarius. The two light-year diameter shroud of dust and gas around a central white dwarf has long been considered an excellent example of a planetary nebula, representing the final stages in the evolution of a sun-like star. But the Spitzer data show the nebula's central star itself is immersed in a surprisingly bright infrared glow. Models suggest the glow is produced by a dust debris disk. Even though the nebular material was ejected from the star many thousands of years ago, the close-in dust could be generated by collisions in a reservoir of objects analogous to our own solar system's Kuiper Belt or cometary Oort cloud. Formed in the distant planetary system, the comet-like bodies have otherwise survived even the dramatic late stages of the star's evolution.
X-rays and the Eagle Nebula (2007-02-24)
The premier Chandra X-ray Observatory images of M16, the Eagle Nebula, show many bright x-ray sources in the region. Most of the x-ray sources are energetic young stars. They are seen here as colored spots superimposed on the Hubble's well-known optical view of M16's light-year long Pillars of Creation. For example, a blue source near the tip of the large pillar at the upper left is estimated to be an embedded young star 4 or 5 times as massive as the Sun. Still, most of the x-ray sources are not coincident with the pillars themselves, indicating that embedded stars are not common in the dusty structures. The mostly empty pillars are thought to be an indication that star formation actually peaked millions of years ago within the Eagle Nebula.
The Far Side of the Moon (2007-02-25)
Does this moon look familiar? Possibly not, even though it is Earth's Moon.  Locked in synchronous rotation, the Moon always presents its well-known near side to Earth.  But from lunar orbit, Apollo astronauts also grew to know the Moon's far side.  This sharp picture from Apollo 16's mapping camera shows the eastern edge of the familiar near side (top) and the strange and heavily cratered far side of the Moon.  Surprisingly, the rough and battered surface of the far side looks very different from the near side which is covered with smooth dark lunar maria.  The likely explanation is that the far side crust is thicker, making it harder for molten material from the interior to flow to the surface and form the smooth maria.
A Rocket Debris Cloud Drifts (2007-02-26)
What's that cloud drifting in space?  It's not an astronomical nebula -- those appear to stay put. Atmospheric clouds don't look like this.  The answer to last week's sky mystery turned out to be orbiting and expanding debris from the upper stage of a failed Russian rocket that exploded unexpectedly.  The cloud became visible to unaided southern hemisphere observers, and its cause was initially unknown. The above time lapse movie shows the cloud drifting as seen from Australia.  Streaks in and near the cloud are likely large pieces of debris.  The debris cloud is more than an astronomical curiosity -- particles from this cloud and others could become projectiles damaging existing satellites.   As the cloud disperses, many particles will fall to Earth, but many more may help make low Earth orbit an increasingly hostile environment.
Atmospheres Detected for Two Extrasolar Planets (2007-02-27)
Do extrasolar planets have water?  In an attempt to find out, the orbiting Spitzer Space Telescope made detailed observations of the atmospheres of two planets that orbit stars other than our Sun.  Unfortunately, water vapor was not detected in either exoplanet. Spitzer watched star systems HD 209458b and HD 189733b closely in infrared light both before and after the parent stars eclipsed their known planets.   By comparing eclipsed and uneclipsed spectra very closely, astronomers could deduce bright light-emitting atmospheric gasses that were being blocked during eclipse.   Were water vapor one of these atmospheric gases, a new indication that life might exist outside of our Solar System would have been found.   The planets being analyzed are known as hot Jupiters -- they have sizes close to Jupiter but orbits closer to the distance of Mercury. The above illustration shows an artist's depiction of one of these dry worlds. Although no water vapor was detected this time, the techniques of measuring exoplanet atmospheres are quite promising, and the search for distant water and other biomarkers is just beginning.
Stars, Dust and Nebula in NGC 2170 (2007-02-28)
When stars form, pandemonium reigns.  A textbook case is the star forming region NGC 2170.  Visible above are red glowing emission nebulas of hydrogen, blue  reflection nebulas of dust, dark absorption nebulas of dust, and the stars that formed from them.  The first massive stars formed from the dense gas will emit energetic light and winds that erode, fragment, and sculpt their birthplace.  And then they explode.  The resulting morass is often as beautiful as it is complex.  After tens of millions of years, the dust boils away, the gas gets swept away, and all that is left is a naked open cluster of stars.
Rosetta Over Mars (2007-03-01)
Panels on ESA's Rosetta spacecraft appear in the foreground of this intriguing image of Mars recorded on February 25 at a range of about 1,000 kilometers. Launched in March 2004, Rosetta was near its closest approach to the Red Planet during a gravity assist flyby maneuver and is ultimately destined to rendezvous with a comet designated 67P/Churyumov-Gerasimenko. Below the comet-chasing spacecraft lies a dark boundary along the martian Syrtis region. But wait ... who took the picture? The picture was actually captured by the imaging system (CIVA) onboard Rosetta's lander, Philae, switched on for testing. The three-legged, box-shaped, 100 kilogram Philae is scheduled to attempt a landing on the comet nucleus after Rosetta's rendezvous in November 2014.
Solar Eclipse from the Moon (2007-03-02)
Parts of Saturday's (March 3) lunar eclipse will be widely visible. For example, skywatchers in Europe, Africa, and western Asia will be able to see the entire spectacle of the Moon gliding through Earth's shadow, but in eastern North America the Moon will rise already in its total eclipse phase. Of course if you traveled to the Moon's near side, you could see the same event as a solar eclipse, with the disk of our fair planet Earth completely blocking out the Sun. For a moon-based observer's view, graphic artist Hana Gartstein (Haifa, Israel) offers this composite illustration. In the cropped version of her picture, an Apollo 17 image of Earth is surrounded with a red-tinted haze as sunlight streams through the planet's dusty atmosphere. Earth's night side remains faintly visible, still illuminated by the dark, reddened Moon, but the disk of the Earth would appear almost four times the size of the Sun's disk, so the faint corona surrounding the Sun would be largely obscured. At the upper left, the Sun itself is just disappearing behind the Earth's limb.
Lunar Transit from STEREO (2007-03-03)
A million miles from planet Earth, last weekend the STEREO B spacecraft found itself in the shadow of the Moon. So, looking toward the Sun, extreme ultraviolet cameras onboard STEREO B were able to record a stunning movie of a lunar transit (aka solar eclipse), as the Moon tracked across the solar disk. Each frame of the movie is a false-color composite of images made through four different filters that highlight temperature regimes and structures in the upper solar atmosphere. In this frame, large bright active regions, seen as dark sunspots in visible light, flank the Moon's silhouetted disk. The Moon appears small, less than 1/4th the size seen from Earth, because the spacecraft-Moon separation is over four times the Earth-Moon distance. Tonight, the Moon will find itself in planet Earth's shadow in a total lunar eclipse.
Triton: Neptune's Largest Moon (2007-03-04)
In October of 1846, William Lassell was observing the newly discovered planet Neptune.  He was attempting to confirm his observation, made just the previous week, that Neptune had a ring. But this time he discovered that Neptune had a satellite as well.  Lassell soon proved that the ring was a product of his new telescope's distortion, but the satellite Triton remained.  The above picture of Triton was taken in 1989 by the only spacecraft ever to pass Triton: Voyager 2.  Voyager 2 found fascinating terrain, a thin atmosphere, and even evidence for ice volcanoes on this world of peculiar orbit and spin.  Ironically, Voyager 2 also confirmed the existence of complete thin rings around Neptune - but these would have been quite invisible to Lassell!
Illusion and Evolution in Galaxy Cluster Abell 2667 (2007-03-05)
What's happening to the galaxies of cluster Abell 2667?  On the upper left, a galaxy appears to be breaking up into small pieces, while on the far right, another galaxy appears to be stretched like taffy.  To start, most of the yellowish objects in the above image from the Hubble Space Telescope are galactic members of a massive cluster of galaxies known as Abell 2667.  The distortion of the galaxy on the upper left is real.  As the galaxy plows through the intercluster medium, gas is stripped out and condenses to form bright new knots of stars.  This detailed image of ram pressure stripping helps astronomers understand why so many galaxies today have so little gas. The distortion of the galaxy on the far right, however, is an illusion.  This nearly normal galaxy is actually far behind the massive galaxy cluster.  Light from this galaxy is gravitationally lensed by Abell 2667, appearing much like a distant person would appear through a wine glass. Each distorted galaxy gives important clues about how galaxies and clusters of galaxies evolve.
Saturn from Above (2007-03-06)
This image of Saturn could not have been taken from Earth.  No Earth based picture could possibly view the night side of Saturn and the corresponding shadow cast across Saturn's rings.  Since Earth is much closer to the Sun than Saturn, only the day side of the planet is visible from the Earth.  In fact, this image mosaic was taken in January by the robotic Cassini spacecraft now orbiting Saturn.   The beautiful rings of Saturn are seen in full expanse, while cloud details are visible near the night-day terminator divide.
New Horizons Spacecraft Passes Jupiter (2007-03-07)
A new spacecraft is headed for the outer Solar System.  Named New Horizons, this robotic explorer passed Jupiter last week after being launched only in early 2006.  New Horizons is being pulled by Jupiter's gravity to a greater speed toward its next target: Pluto in 2015. During its encounter with Jupiter, New Horizons was able to capture new images of many Jovian moons, Jupiter's complex and ever-changing atmosphere, and Jupiter's Little Red Spot, pictured above. Formed over the past few years from several smaller storms, Jupiter's Little Red Spot survived a near miss with Jupiter's better-known Great Red Spot last year. The above image of Jupiter covers over twice the diameter of the Earth.
Eclipsed Moon and Stars (2007-03-08)
This dramatic image features a dark red Moon during a total lunar eclipse -- celestial shadow play enjoyed by many denizens of planet Earth last Saturday. Recorded near Wildon, Austria, the picture is a composite of two exposures; a relatively short exposure to feature the lunar surface and a longer exposure to capture background stars in the constellation Leo. Completely immersed in Earth's cone-shaped shadow during the total eclipse phase, the lunar surface is still illuminated by sunlight, reddened and refracted into the dark shadow region by a dusty atmosphere. As a result, familiar details of the Moon's nearside are easy to pick out, including the smooth lunar mare and the large ray crater Tycho. In this telescopic view, the background stars are faint and most would be invisible to the naked eye.
Eclipse and Ecliptic (2007-03-09)
When a Full Moon lies near the ecliptic there can be a lunar eclipse. That cosmic alignment is well illustrated in this composite of eclipse images recorded last Saturday near Paris, France. The projection of the ecliptic plane, the plane of planet Earth's orbit around the Sun, is traced by the long blue line running diagonally through the picture. At a small angle to the ecliptic, along the Moon's orbit, are a series of images from the eclipse itself following the Moon as it moves (down and left) through Earth's shadow. A small blue circle centered on the ecliptic outlines the extent of the dark region of the shadow or umbra. Above, the principal stars of Leo are highlighted, while at the far right lies another celestial wanderer that stays close to the ecliptic - Saturn.
Eclipse with Lighthouse (2007-03-10)
A red Moon rose over Cape Cod, Massachusetts, USA on March 3rd, immersed in Earth's shadow near the total phase of a lunar eclipse. This serene portrait of the eclipsed Moon in a dark blue twilight sky also features the Highland Lighthouse (aka Cape Cod lighthouse), another more locally familiar beacon in the night. Now automated, the 66 foot tall structure in use today was built in 1857. How often has there been an eclipse within view of the Highland light? For locations on planet Earth there are about two eclipse seasons each year. So, eclipses have actually had many chances to be part of the pictorial history of the Highland Lighthouse, including a total solar eclipse in 1932.
The Einstein Cross Gravitational Lens (2007-03-11)
Most galaxies have a single nucleus -- does this galaxy have four?  The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image.  The central cloverleaf is rather light emitted from a background quasar.  The gravitational field of the visible foreground galaxy breaks light from this distant quasar into four distinct images.  The quasar must be properly aligned behind the center of a massive galaxy for a mirage like this to be evident.  The general effect is known as gravitational lensing, and this specific case is known as the Einstein Cross.  Stranger still, the images of the Einstein Cross vary in relative brightness, enhanced occasionally by the additional gravitational microlensing effect of specific stars in the foreground galaxy.
Watch Jupiter Rotate (2007-03-12)
What would it be like to coast by Jupiter and watch it rotate?   This was just the experience of the New Horizons spacecraft as it approached and flew by Jupiter earlier this year.   Clicking on the image will bring up a movie of what the robotic spacecraft saw. Visible above in the extensive atmosphere of the Solar System's largest planet are bands and belts of light and dark clouds, as well as giant rotating storm systems seen as ovals.  Other movies compiled by New Horizons and other passing spacecraft have captured the clouds swirling and moving relative to themselves.  Jupiter has a diameter of about eleven times that of our Earth, and rotates once in about 10 hours. The robotic New Horizons spacecraft continues to speed toward the outer Solar System where it is expected to approach Pluto in 2015.
Attacking Mars (2007-03-13)
The Spirit rover attacked Mars again in 2005 September.  What might look, above, like a military attack, though, was once again just a scientific one - Spirit was instructed to closely inspect some interesting rocks near the summit of Husband Hill.  Spirit's Panoramic Camera captured the rover's Instrument Deployment Device above as moved to get a closer look at an outcrop of rocks named Hillary.   The Spirit rover, and its twin rover Opportunity, have now been exploring the  red planet for over three years. Both Spirit and Opportunity have found evidence that parts of Mars were once wet.
Barred Spiral Galaxy M95 (2007-03-14)
Why do some spiral galaxies have a ring around the center?  First and foremost, M95 is one of the closer examples of a big and beautiful barred spiral galaxy.  Visible in the above recent image from the CFHT telescope in Hawaii, USA, are sprawling spiral arms delineate by open clusters of bright blue stars, lanes of dark dust, the diffuse glow of billions of faint stars, and a short bar across the galaxy center.  What intrigues many astronomers, however, is the circumnuclear ring around the galaxy center visible just outside the central bar.  Recent images by the Chandra X-ray Observatory have shown that X-ray light surrounding the ring is likely emission from recent supernovas.  Although the long term stability of the ring remains a topic of research, recent observations indicate its present brightness is at least enhanced by transient bursts of star formation. M95, also known as NGC 3351, spans about 50,000 light-years and can be seen with a small telescope toward the constellation of the Lion (Leo).
NGC 2442: Galaxy in Volans (2007-03-15)
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 give it an ominous hook-shaped appearance. This striking color image also shows obscuring dust lanes, young blue star clusters and reddish star forming regions surrounding a core of yellowish light from an older population of stars. But the star forming regions seem more concentrated along the drawn-out northern (top) spiral arm. The distorted structure is likely the result of a close encounter with a smaller galaxy located just outside this telescopic field of view. The picture spans about 1/6 of a degree, or 150,000 light years at the estimated distance of NGC 2442.