omnianasa/nasa-apod-metadata huggingface dataset:
Orion's Horsehead Nebula (2003-01-29)
The Horsehead Nebula is one of the most famous nebulae on the sky.  It is visible as the dark indentation to the red emission nebula seen above and to the right of center in the above photograph.  The bright star on the left is located in the belt of the familiar constellation of Orion. The horse-head feature is dark because it is really an opaque dust cloud which lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will alter its appearance.  The emission nebula's red color is caused by electrons recombining with protons to form hydrogen atoms.  Also visible in the picture are blue reflection nebulae, which preferentially reflect the blue light from nearby stars.
Comet Kudo-Fujikawa: Days in the Sun (2003-01-30)
Cruising through the inner Solar System, new Comet Kudo-Fujikawa reached perihelion, its closest approach to the Sun, yesterday, January 29. Passing within 28.4 million kilometers of the Sun, this comet came much closer than innermost planet Mercury basking only 57.9 million kilometers from our parent star. So close to the Sun, comet Kudo-Fujikawa was extremely bright but impossible for earthbound observers to see against the solar glare. Still, the space-based SOHO observatory captured these views of the comet as it neared perihelion by using a coronograph's occulting disk to block the overwhelming sunlight. In the series of images, the size and location of the blocked-out Sun is indicated by white circles, while arrows point to the traveling comet's bright coma and developing tail. Though fading on its outbound journey, Kudo-Fujikawa should soon be visible to southern hemisphere comet-watchers in February's evening skies.
Auroral Rocket Launch (2003-01-31)
In this striking image, a rocket climbs skyward toward an expansive green auroral display in the first launch of 2003 from the University of Alaska's Poker Flat Research Range. Recorded on January 27th, the view from Cleary Summit near Fairbanks, Alaska shows the fiery tracks of both solid fuel stages of the Black Brant IX sounding rocket that lofted its payload to an altitude of 385 kilometers. Compared to rockets which launch payloads to Earth orbit and beyond, sounding rockets are small and relatively inexpensive. They get their generic name from the nautical term "to sound" which means to take measurements. Known as HIBAR (HIgh Bandwidth Auroral Rocket), this experiment was designed to measure aurora related high-frequency plasma waves which may originate thousands of kilometers above the aurora's visible glow.
The Nebula And The Neutron Star (2003-02-01)
The lonely RX J1856.5-3754 was formed from the collapsed core of an exploding star. At a distance of 180 light-years it is the closest known neutron star. More massive than the Sun but only 20 kilometers across, this tiny stellar juggernaut plows through the hydrogen gas and dust clouds of interstellar space at about 200 kilometers per second. The surface of the neutron star is fantastically hot, around 700,000 degrees Celsius, making it detectable with orbiting x-ray telescopes. But optical astronomers were surprised to discover that RX J1856.5-3754 is also surrounded by a cone-shaped nebula. Indicated in this deep image from the European Southern Observatory's Kueyen telescope, the nebula glows in the red light of ionized hydrogen atoms recombining with electrons. Its cone shape is analogous to the bow wave of a ship plowing through water. A faint blue dot near the tip of the cone is the neutron star itself. The nebula appears to have formed very near the surface of the neutron star and astronomers are trying to determine if the observed densities and temperatures can explain the nebula's appearance.
Molecular Cloud Barnard 68 (2003-02-02)
Where did all the stars go?  What used to be considered a hole in the sky is now known to astronomers as a dark molecular cloud.  Here, a high concentration of dust and molecular gas absorb practically all the visible light emitted from background stars.  The eerily dark surroundings help make the interiors of molecular clouds some of the coldest and most isolated places in the universe.  One of the most notable of these dark absorption nebulae is a cloud toward the constellation Ophiuchus known as Barnard 68, pictured above.  That no stars are visible in the center indicates that Barnard 68 is relatively nearby, with measurements placing it about 500 light-years away and half a light-year across.  It is not known exactly how molecular clouds like Barnard 68 form, but it is known that these clouds are themselves likely places for new stars to form. It is possible to look right through the cloud in infrared light.
Space Shuttle and Crew Lost During Re-Entry (2003-02-03)
Saturday morning, the Space Shuttle Columbia broke up during re-entry.  Pictured above is the seven-member crew that was lost.  True space pioneers, they were, left to right, David M. Brown, Rick D. Husband, Laurel B. Clark, Kalpana Chawla, Michael P. Anderson, William C. McCool, and Ilan Ramon.  As debris from the shuttle may be toxic, NASA asks that anything found be reported immediately to local authorities and not touched.  For the safety of future missions, investigations into the cause of the tragedy are underway.  If you have any video or photographs that may aid in these investigations, NASA asks that you please see  this web page, call (US) 281-483-3388, or send e-mail to columbiaimages@nasa.gov.
Wisps of the Veil Nebula (2003-02-04)
These wisps of gas are all that remain visible of a Milky Way star.  Many thousands of years ago that star exploded in a supernova leaving the Veil Nebula, pictured above. At the time, the expanding cloud was likely as bright as a crescent Moon toward the constellation of Cygnus, visible for weeks to people living at the dawn of recorded history.  The remaining supernova remnant lies about 1400 light-years away and covers over five times the size of the full Moon.  The bright wisp on the right is known as the Witch's Broom Nebula and can be seen with a small telescope.  The Veil Nebula is also known as the Cygnus Loop.
Unusual Gullies and Channels on Mars (2003-02-05)
What could have formed these unusual channels?  Inside Newton Basin on Mars, numerous narrow channels run from the top down to the floor.  The above picture covers a region spanning about 1500 meters across.  These and other gullies have been found on Mars in recent high-resolution pictures taken by the orbiting Mars Global Surveyor robot spacecraft.  Similar channels on Earth are formed by flowing water, but on Mars the temperature is normally too cold and the atmosphere too thin to sustain liquid water.  Nevertheless, many scientists hypothesize that liquid groundwater can sometimes surface on  Mars, erode gullies and channels, and pool at the bottom before freezing and evaporating.  If so, life-sustaining ice and water might exist even today below the Martian surface -- water that could potentially support a human mission to Mars.  Research into this exciting possibility is sure to continue!
X-Rays from M83 (2003-02-06)
Bright and beautiful spiral galaxy M83 lies a mere twelve million light-years from Earth, toward the headstrong constellation Hydra. Sweeping spiral arms, prominent in visible light images, lend this galaxy its popular moniker -- the Southern Pinwheel. In fact, the spiral arms are still apparent in this Chandra Observatory false-color x-ray image of M83, traced by diffuse, hot, x-ray emitting gas. But more striking in the x-ray image is the galaxy's bright central region. The central emission likely represents even hotter gas created by a sudden burst of massive star formation. Point-like neutron star and black hole x-ray sources, final stages in the life cycles of massive stars, also show a concentration near the center of M83 and offer further evidence for a burst of star formation at this galaxy's core. Light from this burst of star formation would have first reached Earth some 20 million years ago.
Orion on Film (2003-02-07)
Orion, the Hunter, is one of the most easily recognizable constellations in planet Earth's night sky. But Orion's stars and nebulae don't look quite as colorful to the eye as they do in this lovely photograph, taken last month from Vekol Ranch south of Phoenix, Arizona, USA. The celestial scene was recorded in a five minute time exposure using high-speed color print film and a 35mm camera mounted on a small telescope. In the picture, cool red giant Betelgeuse takes on a yellowish tint as the brightest star at the upper left. Otherwise Orion's hot blue stars are numerous, with supergiant Rigel balancing Betelgeuse at the lower right, Bellatrix at the upper right, and Saiph at the lower left. Lined up in Orion's belt (left to right) are Alnitak, Alnilam, and Mintaka all about 1,500 light-years away, born of the constellation's well studied interstellar clouds. And if the middle "star" of Orion's sword looks reddish and fuzzy to you, it should. It's the stellar nursery known as the Great Nebula of Orion.
AB Aurigae: How To Make Planets (2003-02-08)
This enhanced Hubble Space Telescope image shows in remarkable detail the inner portion of the disk of dust and gas surrounding the star AB Aurigae. Knots of material, visible here for the first time, may well represent an early stage of a process which could result in the formation of planets over the next few million years. AB Aurigae is a young star (2-4 million years old), about 469 light-years distant. Its swirling circumstellar disk is large, about 30 times the size of our solar system. Astronomers believe planet-making is just beginning in AB Aurigae's disk because known disks surrounding younger stars (less than 1 million years old) do not show such clumpy structure, while disks of slightly older stars (aged 8-10 million years) have gaps and features suggesting that planets have already been formed. Why the window pane appearance? Wide black stripes in the picture are caused by occulting bars used to block out the overwhelming starlight. The diagonal streaks are due to diffraction spikes.
COBE Dipole: Speeding Through the Universe (2003-02-09)
Our Earth is not at rest.  The Earth moves around the Sun.  The Sun orbits the center of the Milky Way Galaxy.  The Milky Way Galaxy orbits in the  Local Group of Galaxies.  The Local Group falls toward the Virgo Cluster of Galaxies.  But these speeds are less than the speed that all of these objects together move relative to the cosmic microwave background (CMB).  In the above all-sky map, radiation in the Earth's direction of motion appears blueshifted and hence hotter, while radiation on the opposite side of the sky is redshifted and colder.  The map indicates that the  Local Group moves at about 600 kilometers per second relative to this primordial radiation.  This high speed was initially unexpected and its magnitude is still unexplained.  Why are we moving so fast? What is out there?
Comet NEAT Approaches the Sun (2003-02-10)
A comet may likely become visible to the unaided eye over the next few days above the horizon where the Sun has just set.  Comet NEAT (C/ 2002 V1), discovered last November, has brightened dramatically as it approached the Sun.  Over the next few days, the quickly setting comet could appear as bright as second magnitude.  On February 18 it will round the Sun well within the orbit of Mercury.  During surrounding days, the Sun's glare will effectively hide the comet to human observers.  It is quite probable, though, that Comet NEAT will standout prominently in images taken by the Sun-looking SOHO satellite.  Pictured above, Comet NEAT's complex and developing tail was photographed on January 29 (top) and February 2.  Sky enthusiasts should remember to never look directly at the Sun.   APOD Update: APOD mirror now on-line from Australia.
Dumbbell Nebula Close-Up from Hubble (2003-02-11)
What causes unusual knots of gas and dust in planetary nebulas?  Seen previously in the Ring Nebula, the Helix Nebula, and NGC 2392, the knots' existence was not predicted previously and still not well understood.  Pictured above is a newly released image of the Dumbbell Nebula by the Hubble Space Telescope showing details of its gaseous knots.  Also visible are many bright young stars and dark sheets of interstellar dust.  The Dumbbell Nebula, also known as M27, is a planetary nebula thought similar to what our Sun will become when it runs out of core fuel for nuclear fusion.  Recent study of similar cometary knots indicates that they include concentrations of relatively cold molecular gas and that they change significantly as the planetary nebula ages.   APOD Update: APOD now also available from Japan in Japanese.
WMAP Resolves the Universe (2003-02-12)
Analyses of a new high-resolution map of microwave light emitted only 380,000 years after the Big Bang appear to define our universe more precisely than ever before.  The eagerly awaited results from the orbiting Wilkinson Microwave Anisotropy Probe resolve several long-standing disagreements in cosmology rooted in less precise data.  Specifically, present analyses of above WMAP all-sky image indicate that the universe is 13.7 billion years old (accurate to 1 percent), composed of 73 percent dark energy, 23 percent cold dark matter, and only 4 percent atoms, is currently expanding at the rate of 71 km/sec/Mpc (accurate to 5 percent), underwent episodes of rapid expansion called inflation, and will expand forever.  Astronomers will likely research the foundations and implications of these results for years to come.   APOD Update: APOD now available in Portuguese from Brazil.
The Eagle Nebula from CFHT (2003-02-13)
Bright blue stars are still forming in the dark pillars of the Eagle Nebula.  Made famous by a picture from the Hubble Space Telescope in 1995, the Eagle Nebula shows the dramatic process of star formation.  To the upper right of the nebula in the above picture lies the heart of the open cluster M16.  The bright blue stars of M16 have been continually forming over the past 5 million years, most recently in the famous central gas and dust pillars known as elephant trunks.  Light takes about 7000 years to reach us from M16, which spans about 20 light years and can be seen with binoculars toward the constellation of Serpens.
The Heart in NGC 346 (2003-02-14)
Yes, it's Valentine's Day (!) and looking toward star cluster NGC 346 in our neighboring galaxy the Small Magellanic Cloud, astronomers have noted this heart-shaped cloud of hot, x-ray emitting gas in the cluster's central region. The false-color Chandra Observatory x-ray image also shows a strong x-ray source just above the heart-shaped cloud which corresponds to HD 5980, a remarkable, massive binary star system that lies within the cluster. HD 5980 has been known to undergo dramatic brightness variations, in 1994 briefly outshining all other stars in the Small Magellanic Cloud, and has been likened to the luminous, eruptive variable star Eta Carinae in our own Milky Way galaxy. At about 100 light-years across, NGC 346's heart-shaped cloud is probably the result of an ancient supernova explosion. Alternatively it may have been produced during past eruptions from the HD 5980 system, analogous to the nebula associated with Eta Carinae.
Happy Birthday Jules Verne (2003-02-15)
One hundred seventy-five years ago (on February 8th), Jules Verne was born in Nantes, France. Inspired by a lifelong fascination with machines, Verne wrote visionary works about "Extraordinary Voyages" including such terrestrial travels as Around the World in 80 Days, Journey to the Centre of the Earth, and Twenty Thousand Leagues Under the Sea. In 1865 he published the story of three adventurers who undertook a journey From the Earth to the Moon. Verne's characters rode a "projectile-vehicle" fired from a huge cannon constructed in Florida, USA. Does that sound vaguely familiar? A century later, the Saturn V rocket and NASA's Apollo program finally turned this work of fiction into fact, propelling adventuresome trios on what was perhaps Verne's most extraordinary voyage. This dramatic view shows the moonbound Apollo 11 space-vehicle riding top a Saturn V rocket as it blasts skyward. Launched from a spaceport in Florida, the Apollo 11 crew traveled to the moon and back again in 1969, making humanity's first landing on the lunar surface.
Southwest Mercury (2003-02-16)
The planet Mercury resembles a moon. Mercury's old surface is heavily cratered like many moons.  Mercury is larger than most moons but smaller than  Jupiter's moon Ganymede and Saturn's moon Titan.  Mercury is much denser and more massive than any moon, though, because it is made mostly of iron. In fact, the Earth is the only planet more dense.  A visitor to Mercury's surface would see some strange sights.  Because Mercury rotates exactly three times every two orbits around the  Sun, and because Mercury's orbit is so elliptical, a visitor to Mercury might see the Sun rise, stop in the sky, go back toward the rising horizon, stop again, and then set quickly over the other horizon.  From Earth, Mercury's proximity to the Sun causes it to be visible only for a short time just after sunset or just before sunrise.
Universe Age from Microwave Background (2003-02-17)
The above sky map tells us the universe is 13.7 billion years old -- but how? At first look, one only sees the microwave glow of gas from our Milky Way Galaxy, coded red, and a spotty pattern of microwaves emitted from the early universe, coded in gray.  The gray cosmic microwave background is light that used to bounce around randomly but came directly to us when the expanding universe became cool enough for nearly transparent atoms to form.  A close inspection of the spots reveals a slightly preferred angular distance between them.  One expects such a pattern to be generated by sound emanating from slightly over-dense regions of the early universe.  Sound waves will take time to generate such a pattern, and the present age of the universe can then be directly extrapolated.  The above universe age is estimated to be accurate to better than 0.2 billion years.  The above map was taken by the WMAP satellite orbiting the Sun at the L2 point, just outside the orbit of the Earth.
Candor and Ophir Chasmata (2003-02-18)
First imaged by the Mariner 9 spacecraft, Valles Marineris, the grand canyon of Mars, is a system of enormous depressions called chasmata that stretch some 4,000 kilometers along the Martian equator. Looking north over the canyon's central regions, Candor chasma lies in the foreground of this spectacular view with the steep walls of Ophir chasma near the top. Surface collapse and landslides are seen to be part of the complex geologic history of these dramatic features but recent high resolution images have also revealed layered deposits within the canyon system. This picture represents a mosaic of images recorded in 1978 from Martian orbit by the Viking 1 and 2 spacecraft. The full width of the picture covers about 800 kilometers.
Pauli Exclusion Principle: Why You Don't Implode (2003-02-19)
Why doesn't matter just bunch up?  The same principle that keeps neutron stars and white dwarf stars from imploding also keeps people from imploding and makes normal matter mostly empty space.  The observed reason is known as the Pauli Exclusion Principle.  The principle states that identical fermions -- one type of fundamental matter -- cannot be in the same place at the same time and with the same orientation.  The other type of matter, bosons, do not have this property, as demonstrated clearly by recently created Bose-Einstein condensates.  Recently, the Pauli Exclusion Principle was demonstrated graphically in the above picture of clouds of two isotopes of lithium -- the left cloud composed of bosons while the right cloud is composed of fermions.  As temperature drops, the bosons bunch together, while the fermions better keep their distance.  The reason why the Pauli Exclusion Principle is true and the physical limits of the principle are still unknown.
Cold Wind from the  Boomerang Nebula (2003-02-20)
A cold wind blows from the central star of the Boomerang Nebula. Seen here in a detailed false-color image recorded in 1998 by the Hubble Space Telescope, the nebula lies about 5,000 light-years away towards the grand southern constellation of Centaurus. The symmetric cloud appears to have been created by a high-speed wind of gas and dust blowing from an aging central star at speeds of nearly 600,000 kilometers per hour. This rapid expansion has cooled molecules in the nebular gas to about one degree above absolute zero - colder than even the cosmic background radiation - making it the coldest region observed in the distant Universe. Shining with light from the central star reflected by dust, the frigid Boomerang Nebula is believed to be a star or stellar system evolving toward the planetary nebula phase.
Melting Snow and the Gullies of Mars (2003-02-21)
Tantalizing images of gullies on Mars have offered striking evidence for recent flows of liquid water. But Mars is too cold and its atmosphere too thin for liquid water to exist on the surface. Still a new and compelling explanation for gullies carved by liquid water was inspired by this recently released image from the Mars Odyssey spacecraft. Pictured is a section of what is likely a snow covered crater in the Martian southern hemisphere. North is at the top and the scene, illuminated from the left, is about 16 kilometers wide. Patches of smooth snow pack remain along the northern crater wall, while structures resembling the famous Martian gullies appear to be emerging as the snow cover gradually disappears, and are exposed along the crater's western (left) wall. Melting snow, running underneath the snow pack and down the crater walls would be protected from the extreme surface conditions, remaining liquid and eroding the gullies over time. Could life exist in a liquid water environment beneath the Martian snow?
Infrared Saturn (2003-02-22)
This delightfully detailed false-color image of Saturn was taken in January 1998 by the orbiting Hubble Space Telescope. The picture is a combination of three images from Hubble's NICMOS instrument and shows the lovely ringed planet in reflected infrared sunlight. Different colors indicated varying heights and compositions of cloud layers generally thought to consist of ammonia ice crystals. The eye-catching rings cast a shadow on Saturn's upper hemisphere. The bright stripe seen within the left portion of the shadow is infrared sunlight streaming through the large gap in the rings known as the Cassini Division. Two of Saturn's many moons have also put in an appearance, Tethys just beyond the planet's disk at the upper right, and Dione at the lower left. Presently, Saturn shines brightly in evening skies as a pale yellow "star" near the constellation Orion.
A Twisted Solar Eruptive Prominence (2003-02-23)
A huge eruptive prominence is seen moving out from our Sun in this condensed half-hour time-lapse sequence.  Ten Earths could easily fit in the "claw" of this seemingly solar monster.  This large prominence, though, is significant not only for its size, but its shape.  The twisted figure eight shape indicates that a complex  magnetic field threads through the emerging solar particles.  Recent evidence of differential rotation inside the Sun might help account for the surface explosion.  The sequence was taken early in the year 2000 by the Sun-orbiting SOHO satellite.  Although large prominences and energetic Coronal Mass Ejections (CMEs) are relatively rare, they are occurred more frequently near Solar Maximum, the time of peak sunspot and solar activity in the eleven-year solar cycle.