omnianasa/nasa-apod-metadata huggingface dataset:
Lunokhod 1: Moon Robot (1996-01-13)
On November 17, 1970 the Soviet Luna 17 spacecraft landed the first roving remote-controlled robot on the Moon. Known as Lunokhod 1, it weighed just under 2,000 pounds and was designed to operate for 90 days while guided by a 5-person team on planet Earth at the Deep Space Center near Moscow, USSR. Lunokhod 1 actually toured the lunar Mare Imbrium (Sea of Rains) for 11 months in one of the greatest successes of the Soviet lunar exploration program. The futuristic looking eight wheeler is pictured here in an artist's conception atop its landing module. Ramps extend from both sides of the spacecraft allowing the rover to choose an alternative route to the surface if one side is blocked by boulders.
A Distant Cluster of Galaxies (1996-01-14)
very bright object in this 1994 photograph by the Hubble Space Telescope is a galaxy. Oddly - most of the objects are  spiral galaxies. This rich cluster of galaxies, named CL 0939+4713, is almost half way across the visible universe. Photos like this indicate that clusters in the past contained a higher fraction of spirals than do nearby clusters, which are usually dominated by elliptical galaxies.
The Dawn of the Clusters (1996-01-15)
What did the universe look like near the beginning?  This exciting photo by the Hubble Space Telescope is one of the deepest ever taken, and shows galaxies as far away as ever before photographed. The universe back then - when only one third of its present age - was a strange and violent place. Back then a large fraction of galaxies were colliding and interacting. In fact, the shapes of many galaxies in the above photo are more distorted than most nearby galaxies. At this early universe epoch many clusters of galaxies were just forming. The bright twisted group of galaxies below the photographs center contains the energetic radio galaxy 3C324.
Wild Duck Open Cluster M11 (1996-01-16)
Many stars like our Sun were formed in open clusters.  The above open cluster, M11, contains thousands of stars and is just over three thousand light years distant.  The stars in this cluster all formed together about 150 million years ago. The many bright stars in the cluster appear blue. Open clusters, also called  galactic clusters, contain fewer and younger stars than globular clusters.  Also unlike globular clusters, open clusters are generally confined to the plane of our Galaxy.
NGC 7027: A Dying Star's Nebula (1996-01-17)
This pseudo-color composite of two recent Hubble Space Telescope images is a picture of a Sun-like star nearing the end of its lifetime. The exquisite details visible in this planetary nebula indicate that when the star passed through its Red Giant phase it initially shrugged off its outer atmosphere gently and evenly producing the outer faint spherical shells. As the process continued, material was apparently ejected in dense clumps producing dust clouds in the bright inner regions. The whole ejection process was amazingly rapid, taking only a few thousand years compared to a 10 billion year lifetime typical for Solar type stars. In the end the hot stellar core, now a white dwarf star, was left - seen here as a white dot at the center of the nebula. Our middle-aged Sun will experience a similar fate ... in about 5 billion years!
MyCn18: An Hourglass Nebula (1996-01-18)
The sands of time are running out for the central star of this hourglass-shaped planetary nebula. With its nuclear fuel exhausted, this brief, spectacular, closing phase of a Sun-like star's life occurs as its outer layers are ejected - its core becoming a cooling, fading White Dwarf. Astronomers have recently used the Hubble Space Telescope (HST) to make a series of images of planetary nebulae, including the one above. Here, delicate rings of colorful glowing gas (nitrogen-red, hydrogen-green, and oxygen-blue) outline the tenuous walls of the "hourglass". The unprecedented sharpness of the HST images has revealed surprising details of the nebula ejection process and may help resolve the outstanding mystery of the variety of complex shapes and symmetries of planetary nebulae.
The Dusty Disk of Beta Pic (1996-01-19)
This dusty disk, viewed edge on surrounding Beta Pictoris, a star only 50 lightyears distant, may signal the presence of an infant solar system. Beta Pictoris is a young Sun-like star just completing its formative stages. About 10 years ago it made the news when astronomers detected a disk around the star because planets are expected to form in such circumstellar disks. Did planets form around Beta Pic? The above recent Hubble Space Telescope image offers supporting evidence that they did. In this false color image, the overwhelming light from the star itself is masked out and features of the inner disk are revealed. The inner part (white area) appears to be slightly warped with respect to the line centered on the axis of the outer parts of the disk. This warp could be caused by a large planet orbiting within the inner clear zone, too faint to be seen directly against the stellar glare. If so, this is an indication that planetary systems are common in our galaxy. Is anybody out there?
Mercury's Caloris Basin (1996-01-20)
Mercury, the closest planet to the Sun, has a surface with so many craters it resembles the Earth's Moon. The largest surface feature on Mercury is the Caloris Basin, which resulted from a collision with an asteroid.  The basin, which is more that 1000 kilometers across, is visible as the large circular feature at the bottom of the above photograph. Similar features, such as the Mare Orientale, are seen on the Moon. The Caloris Basin gets very hot because it is near the "sub-solar point" - the point on Mercury's surface that is directly under the Sun when Mercury is closest to the Sun.
Mercury's Faults (1996-01-21)
The surface of the planet Mercury is not without fault. In this case, however, "fault" refers to unusual surface features that are the topic of much speculation. The above fault line is called Santa Maria Rupes, and runs through many prominent craters. The meandering feature is thought to be the result of huge forces of compression on Mercury's surface. Such rupes probably originate from large impacts and a general shrinking of Mercury's crust, which in turn causes parts of the crust to push above other parts.
Betelgeuse, Betelgeuse, Betelgeuse (1996-01-22)
Betelgeuse (sounds a lot like "beetle juice"), a red supergiant star about 600 lightyears distant, is shown here in this Hubble Space Telescope image which represents the first direct picture of the surface of a star other than the Sun. While Betelgeuse is cooler than the Sun, it is more massive and over 1000 times larger - if placed at the center of our Solar System, it would extend past the orbit of Jupiter. This image reveals a bright, as yet unexplained hotspot on its surface. Betelgeuse is also known as Alpha Orionis, one of the brightest stars in the familar constellation of Orion, the Hunter. Like many star names, Betelgeuse is Arabic in origin. It is derived from a phrase which refers to the hunter's shoulder or armpit, the general area occupied by this star in drawings of the figure in the constellation. As a massive red supergiant, it is nearing the end of its life and will soon become a supernova.
The Deep Field (1996-01-24)
The image above is part of the Hubble Deep Field and represents humanity's most distant yet optical view of the Universe. Galaxies like colorful pieces of candy fill the field, some as faint as 30th magnitude (about four billion times fainter than stars visible to the unaided eye). The dimmest objects are the most distant galaxies and reveal what the Universe looked like in the extremely distant past, perhaps less than one billion years after the Big Bang. To make the Deep Field image, astronomers selected an uncluttered area of the sky in the constellation Ursa Major (the Big Dipper) and pointed the Hubble Space Telescope at a single spot for 10 days accumulating and combining many separate exposures. With each additional exposure, fainter objects were revealed. The final result can be used to explore the mysteries of galaxy evolution and the infant Universe.
Catching Falling Stardust (1996-01-25)
This carrot shaped track is actually little more than 5 hundredths of an inch long. It is the trail of a meteroid through a gel exposed to space in low earth orbit by the shuttle launched EURECA (European Recoverable Carrier) spacecraft. The meteoroid itself, about a thousandth of an inch in diameter, is visible where it came to rest, just beyond the tip of the carrot (far right). Chemical analyses of interplanetary dust particles similar to this one suggest that some of them may be bits of comets and represent samples of material from the early stages of the formation of the Solar System. NASA's Stardust mission, planned for launch in 1999, will attempt to directly collect dust from the tail of a comet and return it to Earth.
Quadrantids: Meteors in Perspective (1996-01-26)
Meteor showers are caused by streams of solid particles, dust size and larger, moving as a group through space. In many cases, the orbits of these meteor streams can be identified with the dust tails of comets. When the Earth passes through the streams, the particles leave brilliant trails through the night sky as they burn up in the atmosphere. Above is an image of a meteor shower known as the Quadrantids. It was made in January 1995 using MOVIE, a new system for making video meteor observations. To make the image, frames from a video tape were computer processed and superposed to show the relative paths of many meteors in the shower. The meteor paths are all parallel to each other, but the effect of perspective causes the trails to appear to originate from a distant radiant point in the sky. In contrast to the elongated meteor trails, the brighter stars of the familiar constellation Ursa Major (the Big Dipper) are visible as points in the lower half of the image.
M8: An Open Cluster in the Lagoon (1996-01-27)
The large majestic Lagoon Nebula is home for many young stars and hot gas. The Lagoon Nebulae is so large and bright it can be seen without a telescope. Formed only several million years ago in the nebula is the open cluster known as NGC 6530, whose young stars show their high temperature by their blue glow.  The nebula, also known as M8 and NGC 6523, is named "Lagoon" for the band of dust seen to the left of the open cluster's center.  A bright knot of gas and dust in the nebula's center is known as the Hourglass Nebula. Star formation continues in the the Lagoon Nebula as witnessed by the many globules that exist there.
Orbiting Repairmen (1996-01-28)
In December of 1993 astronauts Story Musgrave and Jeffrey Hoffman performed the orbiting repairmans' ballet 400 miles above the Earth. They are seen in this photo perched at the end of the Space Shuttle Endeavour's robotic arm making final repairs to the four story tall Hubble Space Telescope. The coast line of western Australia is visible below. The complex and highly successful repair mission allowed HST to see into the Universe with unprecedented clarity.
Searchlight Beams from the Egg Nebula (1996-01-29)
The dramatic and mysterious looking object revealed in this Hubble Space Telescope image is known as the Egg Nebula. It is an aging star about 3,000 lightyears distant, entering its Planetary Nebula phase of evolution. Surrounded by an expanding cloud of gas and dust, a dense cocoon of dust (seen as the dark band running diagonally across the center) encloses the star itself and blocks it from direct view. The searchlight appearance is created as light from the star shines more easily through the thinner parts of the cocoon. Dust particles in the expanding cloud scatter and reflect the starlight making the beams visible. The sharpness of the HST image reveals a wealth of detail which will help to understand this complex and spectacular part of the stellar lifecycle.
70 Virginis b: A New Water Planet? (1996-01-30)
The star 70 Virginis has a planet. This recent discovery is the second known case of a planet orbiting a normal star other than our Sun itself. The first case involved 51 Pegasi and was announced last year. The star 70 Vir, shown in the center of the above false-color picture, is very much like the Sun. The planet is not visible above - the unusual structure surrounding the star is caused by the telescope. The planet, designated 70 Vir b for short, was discovered by very slight periodic shifts in its colors. Defining characteristics of this planet include that it is at least eight times the mass of Jupiter, it's orbit is much smaller than Jupiter's, and it's temperature allows water to exist in liquid form - like on the Earth. Life on Earth is based on liquid water - could life exist here too?
Planets Around Sun-Like Stars (1996-01-31)
Do many Sun-like stars have planets? Speculation on this point has been ongoing since humanity's realization that other stars existed. Only in the past year, however, have answers and discoveries been realized. The above plot summarizes the four known cases of normal stars having planets. These cases are: our Solar System, 51 Pegasi, 70 Virgini, and 47 Ursae Majoris. The later two cases were discovered by astronomers led by Geoff Marcy and Paul Butler as part of a greater project inspecting 120 stars for orbiting planets. Interestingly enough, the planets around the later two stars have temperatures in the right range to allow liquid water - and hence may have conditions ripe for the development of life.
Lensing through Baade's Window (1996-02-01)
What is the shape and composition of our Milky Way Galaxy? This question would be easier to answer if there wasn't so much obscuring dust! In the 1940s, however, astronomer Walter Baade identified a "window" near the center of our Galaxy where there is comparatively little opaque dust. Now called "Baade's Window", this sky region contains millions of stars and is used for many studies of the distant Milky Way. One clever use, devised by Bohdan Paczynski, is to monitor millions of stars in our Galactic Bulge - many through Baade's window - for sudden brightening due to gravitational lensing. Current observations by the OGLE and MACHO collaborations have now identified dozens of gravitational amplification events. This unexpectedly large number supports previous claims that our Galaxy has a "bar" of stars across the central nucleus, pointed nearly at the Sun.
A MACHO View of Galactic Dark Matter (1996-02-02)
What is our Galaxy made of?  Stellar motions indicate there is much more mass than just stars and gas. Photographs like the two shown above may be yielding a clue about the dark matter, however. Pictured is the first recorded instance of a dim star in our Galaxy moving in front of a bright background star, shown by the arrow, deflecting light around it, and causing the background star to appear much brighter (right frame). Were our Galaxy made predominantly of MAssive Compact Halo Objects (MACHOs), many similar such gravitational lensing events would be expected when photographing the Large Magellanic Clouds (LMC) - hence indicating the presence of MACHO lenses in our Galaxy. A research team led by Charles Alcock this month claimed enough LMC gravitational lensing events to indicate at least half of the dark matter in our Galaxy is composed of MACHOs. This spectacular claim may well be correct - but awaits crucial testing with future observations and modeling.
A Huge Impact Crater on Mars (1996-02-03)
What hit Mars? The impact crater Schiparelli near the center of the above image was likely caused by a collision with an object the size of an asteroid. Also evident in this full face mosaic of Mars are numerous craters from many other impacts with smaller objects over billions of years. At the lower right, white carbon dioxide frost can be seen in the Hellas basin. The frost forms because temperatures can drop as low as -140 degrees Celsius on Mars. Some Martian regions, however, occasionally reach as high as 20 degrees Celsius - a typical room temperature here on Earth.
The Closest Galaxy: The Sagittarius Dwarf (1996-02-04)
What's the closest galaxy to our Milky Way?  For many years astronomers thought it was the Large Magellanic Cloud (LMC). But the seemingly insignificant fuzzy patch shown above turned out to be part of a galaxy that is even closer. Deemed the "Sagittarius Dwarf", this small galaxy went unnoticed until its discovery in 1994 by R. Ibata, G. Gilmore and M. Irwin (RGO).  The reason the Sagittarius Dwarf hadn't been discovered earlier is because it is so dim, it is so spread out over the sky, and there are so many Milky Way stars in front of it. The distance to the Sagittarius Dwarf was recently measured to be about one third of the distance to the LMC. Astronomers now believe that this galaxy is slowly being torn apart by the vast gravitational forces of our Galaxy.
COBE Dipole: Speeding Through the Universe (1996-02-05)
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. 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 microwave background. 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?
COBE Hotspots: The Oldest Structures Known (1996-02-06)
Above are two microwave images of the sky, looking north and south of our galaxy's equator, based on data from NASA's COBE satellite. After computer processing to remove contributions from nearby objects and the effects of the earth's motion, they show "spots". These spots are the oldest structures known - probably the oldest structures humanity will ever know. They are also the most distant. As our universe expanded and cooled, conglomerations of mass formed - these are some of the first. They confirm that only a million years after the big-bang - which occurred roughly 15 billion years ago - parts of the universe were visibly hotter than other parts. By studying the size and distribution of the spots found with COBE and future missions, astronomers hope to learn what matter and processes caused the spots to form - and hence determine the composition, density, and future of our universe.
If You Could Stand on Mars (1996-02-07)
If you could stand on Mars - what would you see? Viking 1 robot landers answered this question in 1976 with pictures like the one shown above. The dark rocks, red soil, and green-tinged sky grace this rendition of a normal Martian afternoon. At the bottom corners of the picture are portions of Viking spacecraft. The red color of the rocks is caused by an abundance of iron in the soil. The Martian surface is covered by rocks, huge craters, fantastic canyons, and gigantic volcanoes that dwarf any on Earth. No life has been found, but some speculate that since not all spacecraft reaching Mars from Earth had been fully decontaminated, Earth born microbes might live there now.
Hyakutake: The Great Comet of 1996? (1996-02-08)
Get ready for one of the most impressive but least anticipated light shows in modern astronomical history. Next month, newly discovered Comet Hyakutake will pass closer to the Earth than any recent comet. Unknown before its discovery by Yuji Hyakutake on 30 January 1996, the fuzzy spot in the above photograph is a comet now predicted to become bright enough to see without a telescope. Although comets act in such diverse ways that predictions are frequently inaccurate, even conservative estimates indicate that this comet is likely to impress. For example, even if Comet Hyakutake remains physically unchanged, its close pass near the Earth in late March 1996 should cause it to appear to brighten to about 3rd magnitude - still bright enough to see with the unaided eye. In the next two months, though, the comet will continue to approach the Sun and hence should become brighter still. Optimistic predictions include that Comet Hyakutake will change physically, develop a larger coma and tail, brighten dramatically, move noticeably in the sky during a single night, and may ultimately become known as the "The Great Comet of 1996." Move over Hale-Bopp!
The Eye of an Hourglass Nebula (1996-02-09)
What's happening in the eye-like center of this planetary nebula?  The geometry revealed in this Hubble Space Telescope view of the central part of an "etched hourglass nebula" known as MyCn 18 presents a puzzle. First, the axis of this central region does not line up well with the outer hourglass structure. Next, the hot star (the white spot to the left of center) which ejected this gaseous nebula as it evolved towards its white dwarf phase, is not exactly at the center of the "eye". These unexpected results leave astronomers looking for the missing pieces of the ejection process that created this unusual and beautiful structure.
The First Explorer (1996-02-10)
The first US spacecraft was Explorer 1. The cylindrical 30 pound satellite was launched (above) as the fourth stage of a Jupiter-C rocket (a modified US Army Redstone ballistic missile) and achieved orbit on January 31, 1958. Explorer I carried instrumentation to measure internal and external temperatures, micrometeorite impacts, and an experiment designed by James A. Van Allen to measure the density of electrons and ions in space. The measurements made by Van Allen's experiment led to an unexpected and startling discovery - an earth-encircling belt of high energy electrons and ions trapped in the magnetosphere - now known as the Van Allen Belt. Explorer I ceased transmitting on February 28 of that year but remained in orbit until March of 1970.
Sputnik: The Traveling Companion (1996-02-11)
Sputnik means "traveling companion". In stark contrast to this innocent sounding name, the launch of the Earth's first "artificial moon", Sputnik 1, by the Soviets on October 4, 1957 shocked the free world, setting in motion events which resulted in the creation of NASA and the race to the Moon. Sputnik I was a 184 pound, 22 inch diameter sphere with four whip antennas connected to battery powered transmitters. The transmitters broadcast a continuous "beeping" signal to an astounded earthbound audience for 23 days. A short month later, on November 3, the Soviets followed this success by launching a dog into orbit aboard Sputnik 2.
Pluto Not Yet Explored (1996-02-12)
Cold, distant, Pluto is the only planet in our Solar System which has not been visited by a spacecraft from Earth. The story goes that the legend "Pluto Not Yet Explored" on a US postal stamp depicting the tiny, mysterious world inspired a JPL employee to develop plans for a Pluto flyby. These plans evolved into the current "Pluto Express" mission intended for launch early in the next decade. The type of small, high-tech spacecraft proposed is depicted above in an artist's vision approaching Pluto's mottled surface. A tenuous, transient atmosphere is visible as blue haze beyond the bright limb while Pluto's companion Charon looms in the distance. Images and data from such a mission would be an incredible boon to those studying these bizarre, inaccessible worlds as evidence mounts that Pluto itself is only the largest of many small ice dwarf mini-planets. Some have dubbed the yet unexplored Pluto-Charon system the last "astronomers' planet". Note: Pluto's discoverer, astronomer Clyde Tombaugh, celebrated his 90th birthday on February 4.