omnianasa/nasa-apod-metadata huggingface dataset:
A View from Venus: Rift Valley (1996-06-24)
Color information from the Soviet Venera landers and radar data from the Magellan spacecraft were used to construct this striking perspective view of the Venusian landscape. (In this computer generated image, the vertical scale has been exagerated.) In the foreground is the edge of a rift valley created by faulting in the crust of Venus. The valley runs all the way to the base of Gula Mons, a 2 mile high volcano seen here on the right, some 450 miles in the distance. On the left is another volcano, Sif Mons. Using radar to pierce the dense clouds continuously shrouding the Face of Venus, Magellan was able to explore over 98% of the Venusian surface, revealing a a diverse and tantalizing topography.
A Star Forming Region in the LMC (1996-06-25)
Stars sometimes form in colorful ways.  Pictured above is a small region in the nearby LMC galaxy where stars are forming. After a star is born, it may do several things to energize its immediate neighborhood. It may develop a strong wind which pushes away nearby gas; it may be so hot and intense that emitted light boils away nearby dust and gas, and it may be so massive that it soon goes supernova and catapults its elements back to the interstellar medium. Astronomers study regions like this - named DEM192 - to better understand how these and other processes proceed. This picture is a composite of three separate photographs, each sensitive to only one specific color of light - a color that distinguishes a specific chemical element.
Happy Birthday Charles Messier: M1 (1996-06-26)
French astronomer Charles Messier was born on June 26, 1730. Inspired by childhood sightings of comets and a solar eclipse visible from his home town of Badonvillier, he became an astronomer and comet hunter who kept careful records of his observations. While hunting for comets in the skies above France he made a now famous list of the positions of about 100 fuzzy, diffuse looking objects which appeared at fixed positions in the sky. Although these objects looked like comets, Messier knew that since they did not move with respect to the background stars they could not be the comets he was searching for. These objects are now well known to modern astronomers to be among the brightest and most striking nebulae, star clusters, and galaxies. Objects on Messier's list are still referred to by their "Messier number". The first object in his catalog, M1 pictured above - also known as the Crab Nebula, was recorded during his search for the return of comet Halley in 1758. Messier died in his home in Paris in 1817.
Voyager's Preview of Galileo at Ganymede (1996-06-27)
NASA's robot spacecraft Galileo began its long voyage to Jupiter in October of 1989. In December of last year it arrived in the Jovian system, beginning its unprecedented, detailed exploration by dropping a probe into the gas giant's atmosphere. By early this morning it will have accomplished another milestone in its ambitious mission. Now in orbit around Jupiter, Galileo will make its first close flyby of Ganymede, Jupiter's (and the solar system's) largest moon at 2:29 a.m. EDT. As planned, approaching to within 524 miles, it will make a series of high resolution images of the surface which will reveal features as small as 33 feet across. This close-up color image from the Voyager 2 flyby in 1979 previews sights Galileo will see in greater detail. Showing features as small as 3 miles across, it reveals a variety of terrain on Ganymede's icy surface, including impact craters with bright rays and long strips of light grooved structures suggesting large scale motions of the frozen crust. Galileo's flyby images will be stored onboard for playback and should be available during the week of July 10.
A Distant Galaxy in the Deep Field (1996-06-28)
Researchers believe that the faint reddish smudge indicated by the arrow in the image above is a candidate for the most distant known galaxy which may have existed only a few hundred million years after the Big Bang. The image is part of the Hubble Deep Field, the Hubble Space Telescope's deepest yet picture of the Universe. Made in December 1995 by staring for ten consecutive days with the Hubble, astronomers have been intently studying the resulting deep field image filled with remote galaxies for clues to what galaxies and the Universe looked like in the distant past. While nearby galaxies are easily detected in the image - some seen here have visible elliptical and even spiral structures - the most distant (and therefore oldest) galaxies must be identified by examining their appearance in different wavelengths of light. Based on this technique, six of the most distant galaxies in the Deep Field appear to be farther away than even quasars.
The Voyagers' Message in a Bottle (1996-06-29)
Launched in the summer of 1977, NASA's Voyager 1 and 2 spacecraft are now over 4.5 billion miles from the Sun. Still operational, the Voyagers are being tracked and commanded through the Deep Space Network. Having traveled beyond the outer planets, these remarkable spacecraft are only the third and fourth human built artifacts to escape our solar system, following in the footsteps of Pioneer 10 and 11. A 12-inch gold plated copper disk (pictured) containing recorded sounds and images representing human cultures and life on Earth, is affixed to each Voyager - a message in a bottle cast into the cosmic sea. The recorded material was selected by a committee chaired by Carl Sagan of Cornell University. The disks are intended to be played like a phonograph record at 16 and 2/3 revolutions per second. Cartridge and needle are supplied, along with some simple diagrams (visible above) which represent symbolically the spacecraft's origin and instructions for playing the disk. The exotic construction of the disks should provide them with a long lifetime as they coast through interstellar space. The two spacecraft will not make a close approach to another planetary system for at least 40,000 years.
Greetings from the Pioneers (1996-06-30)
Launched in the early 1970s Pioneer 10 and 11 were appropriately named - becoming the first spacecraft to travel through the asteroid belt, first to fly by Jupiter and Saturn, and the first human artifacts to venture beyond the solar system. Now coasting through interstellar space, they carry with them greetings in the form of a gold anodized plaque with symbolic drawings as illustrated above. The male and female figures are drawn to the same scale as the Pioneer spacecraft shown behind them. Immediately to the left is a map of the position of the sun with respect to nearby pulsars and the center of the galaxy while below is a drawing of the solar system indicating the planet of origin. In the upper left is a schematic of two fundamental states of the hydrogen atom. These diagrams along with other details of the plaque were designed by Carl Sagan of Cornell University and are intended to be decipherable by spacefaring extraterrestrial civilizations.
Worlds of a Distant Sun: 47 Ursae Majoris b (1996-07-01)
Within the last few years, observational astronomy has given humanity evidence of the existence of worlds beyond the solar system. Indeed, solar-type stars are now inferred to harbor planets of approximately Jupiter mass - some residing in temperature zones which could conceivably support liquid water and therefore life! Above is a hypothetical scene near one such planet whose sun, 47 Ursae Majoris (47 UMa), is a yellow dwarf star (spectral class G0 V) very similar to our own. In our sky, it appears as a faint, inconspicuous star below the cup of the northern hemisphere asterism, "the Big Dipper". (Our own sun would be equally inconspicuous when viewed from 47 UMa ...) Astronomer's G. Marcy and P. Butler announced the discovery of a planet associated with this star in 1996 and reported it to have a mass of about 2.4 Jupiters or more with an orbital period of 3 years. This artist's vision pictures the detected planet, referred to as 47 UMa b, as a gas giant surrounded by a ring of material - analogous to our own gas giant Saturn. In the foreground lies a hypothetical moon of 47 UMa b.  Could such a moon support life? 47 UMa is only 44 light years distant, fairly close by astronomical standards - yet there is evidence for planetary systems which are closer still. NASA plans to explore nearby planetary systems using spaceborne observatories.   APOD News: RJN to MTU
NASA's Latest Rockets: X-33 (1996-07-02)
What will NASA rockets look like in the future?  Today's announcement gave one indication. Today Vice- President Al Gore announced that the Lockheed Martin Corporation will work with NASA to produce a reusable rocket with a remote pilot. Currently designated the X-33 program, the flight demonstration rocket design will utilize only a single stage, cost relatively little per launch, and be ready for re-launch within days. It is expected that an X-33 type rocket will be in use by NASA by the the year 2000. Pictured above is an artistic depiction of the candidate vehicle.    APOD News: RJN to MTU
Superbubbles in the LMC (1996-07-03)
Why is there a hole in the center of this nebula? A leading explanation is that it is caused by the stellar winds from the stars that live there. Stars - including the Sun - expel electrons, protons, and other charged ions in a steady stream - the stellar wind. The wind ions push out the normal hydrogen and helium gas found glowing in the nebula. This star forming region is located in the Large Magellanic Cloud. This picture is a composite of three separate photographs, each sensitive to only one specific color of light - a color that distinguishes a specific chemical element.  It is currently not known why stars emit a stellar wind.
The Cat's Eye Nebula (Revisited) (1996-07-04)
Three thousand light years away, a dying star throws off shells of glowing gas. This image from the Hubble Space Telescope reveals "The Cat's Eye Nebula" to be one of the most complex planetary nebulae known. In fact, the features seen in this image are so complex that astronomers suspect the bright central object may actually be a binary star system. The term planetary nebula, used to describe this general class of objects, is misleading. Although these objects may appear round and planet-like in small telescopes, high resolution images reveal them to be stars surrounded by cocoons of gas blown off in the late stages of stellar evolution.   APOD News: Policy on Re-Running Pictures
The Mysterious Rings of Supernova 1987a (1996-07-05)
What's causing those odd rings in supernova 1987a?  In 1987, the brightest supernova in recent history occurred in the Large Magellanic Clouds. At the center of the picture is an object central to the remains of the violent stellar explosion. When the Hubble Space Telescope was pointed at the supernova remnant in 1994, however, curious rings were discovered. The origins of these rings still remains a mystery. Speculation into the cause of the rings includes  beamed jets emanating from a dense star left over from the supernova, and a superposition of two stellar winds ionized by the supernova explosion.
Edmond Halley's Greatest Discoveries (1996-07-06)
Sir Edmond Halley was quite a discoverer.  Born in 1656, he computed in 1705 that a bright comet was periodic and would make another appearance in 1758. The comet appeared as predicted and is now known as Comet Halley. Unfortunately, Halley died in 1742 and never saw his prediction come true. In 1716  Halley proposed two types of diving bells that would enable people to explore the deep sea.  Halley pioneered our understanding of trade winds, tides, cartography, naval navigation, mortality tables, and stellar proper motions.  Halley (incorrectly) proposed that the Earth was made of concentric spheres the size of the inner planets each of which might contain life. Perhaps Halley's greatest discovery, however, was that his contemporary Isaac Newton had discovered a powerful mathematical formulation of gravity.
Isaac Newton Explains the Solar System (1996-07-07)
Sir Isaac Newton changed the world. Born in 1643, Newton was only an above-average student. But he went home from Cambridge one summer in 1665, thought a lot about the physical nature of the world, and came back two years later with a revolutionary understanding of mathematics, gravitation, and optics. A Professor of his, upon understanding what Newton had done, resigned his own position at Cambridge so Newton could have it. Newton's calculus provided a new mathematical framework for the rapid solution of whole classes of physical problems.  Newton's law of gravitation explained in one simple formula how apples fall and planets move.  Newton's insights proved to be so overwhelmingly powerful he was the first scientist ever knighted.
M33: The Triangulum Galaxy (1996-07-08)
The spiral galaxy M33 is a mid-sized member of our Local Group of galaxies. M33 is also called the Triangulum Galaxy for the constellation in which it resides. About four times smaller (in radius) than our Milky Way Galaxy and the Andromeda Galaxy (M31), it is much larger than the many of the local dwarf spheroidal galaxies. M33's proximity to M31 causes it to be thought by some to be a satellite galaxy of this more massive galaxy. M33's proximity to our Milky Way galaxy causes it to appear more than twice the angular size of the full moon, and visible with a good pair of binoculars.  In the above picture, visible light is shown in red and ultraviolet light superposed in blue.  Stars in M33 are the most distant ever to be studied spectroscopically.
M74: A Grand Design Spiral Galaxy (1996-07-09)
M74 is about the same size as our own Milky Way Galaxy. Like our Milky Way, M74 is classified a spiral galaxy. M74's sweeping lanes of stars and dust combined with its small nucleus make it a classic Grand Design Spiral. On the Hubble Sequence of Galaxies, M74 is listed as "Sc". In the above picture, visible light is shown in red and ultraviolet light superposed in blue. In general, older stars are more red and younger stars are blue. Studies with the Ultraviolet Imaging Telescope show that the disk of M74 has undergone significant star formation in just the past 500 million years.
Galileo Photographs Ganymede (1996-07-10)
Ganymede's surface is slowly being pulled apart. This photo of Ganymede was released earlier today by the Galileo team at NASA. The Galileo Spacecraft arrived at Jupiter in December 1995. In late June, the spacecraft passed within 10,000 kilometers of Ganymede's icy surface, and took pictures showing complex surface details for the first time. The line-like features in this photo are sunlit ridges rising above Ganymede's ice-plains.  The circular features are impact craters. Ganymede is the largest moon of Jupiter and hence the largest of the four Galilean satellites: Io, Europa, Ganymede, and Callisto.   APOD's Archive of Galileo at Ganymede
Ganymede: A Really Groovy Moon (1996-07-11)
Ganymede's surface is a wrinkled mess. As large ice-sheets shift on the moon's surface, parts of the surface buckle causing high ridges, deep furrows, and parallel grooves. This photo, taken by the Galileo spacecraft currently orbiting Jupiter, was released yesterday. The large circular feature near the picture bottom is a large impact crater. The impact that caused this large crater also caused the strange dark ejecta seen to the crater's right. The Sun illuminates the scene from the lower left. The Galileo spacecraft has also just discovered that Ganymede has a region of orbiting charged particles called a magnetosphere - a first for any moon. How Ganymede is able to generate a magnetosphere is a mystery.   APOD's Archive of Galileo at Ganymede
Ancient Cratered Plains on Ganymede (1996-07-12)
The largest moon in the Solar System shows regions that are ancient and battered. The high density of craters demonstrate that patches of Ganymede are indeed billions of years old. This photo is one of a series released by NASA two days ago from the Galileo spacecraft orbiting Jupiter. The large impact crater on the left is 19 kilometers across, while dark indentations in Ganymede's crusty surface-ice run diagonally.  Ganymede is composed of half rock and half water-ice. The Galileo spacecraft will continue to orbit Jupiter over the next 16 months and send back data about Jupiter and its four largest moons: Io, Europa, Ganymede, and Callisto.   APOD's Archive of Galileo at Ganymede
M81: A Bulging Spiral Galaxy (1996-07-13)
Few stars are still forming in the old giant spiral galaxy M81. The blue regions in this picture - representing ultraviolet light - highlight regions of bright young stars and star formation and appear rare than in M74 and M33. The red regions - representing the visible light - show a large population of older, less massive stars.  M81 is therefore classified as spiral galaxy type "Sab" on the Hubble Sequence of Galaxies. One distinguishing feature of these types of galaxies is the relatively large central bulge surrounding the center of the galaxy. A massive density wave circulates around the center of spiral galaxies. It is not well understood why the bulge of M81 glows as bright as it does in ultraviolet light. Speculation includes that this may be due to hot evolved stars such as those found in the ancient globular cluster Omega Centauri.
M81 in True Color (1996-07-14)
Here's what a spiral galaxy REALLY looks like.  Yesterday, M81 was shown in two colors only, but here we see M81 at its most colorful. In the above picture, note how blue the spiral arms are - this indicates the presence of hot young stars and on-going star formation.  Also note the yellow hue of the nucleus, possibly designating a population of older stars many billions of years old.  M81 is actually a dominant member of a group of galaxies which includes M82 and several other galaxies.  Unlike our Local Group of galaxies, large galaxies in the M81 group are actually colliding. It is possible that M81's interaction with M82 create the density waves which generate M81's spiral structure.
Keck: The Largest Optical Telescope (1996-07-15)
In buildings eight stories tall rest mirrors ten meters across that are slowly allowing humanity to map the universe. Alone, each is the world's largest optical telescope: Keck. Together, the twin Keck telescopes have the resolving power of a single telescope 90-meter in diameter, able to discern sources just milliarcseconds apart. Since opening in 1992, the real power of Keck I (left) has been in its enormous light-gathering ability - allowing astronomers to study faint and distant objects in our Galaxy and the universe. Keck II, completed earlier this year, and its twin are located on the dormant volcano Mauna Kea, Hawaii, USA. In the distance is Maui's volcano Haleakala. One reason Keck was built was because of the difficultly for astronomers to get funding for a smaller telescope.
A Portrait of Saturn from Titan (1996-07-16)
The above artistic portrait of Saturn depicts how it might look from Titan, Saturn's largest moon. In the foreground sits ESA's Huygens probe, which will be released by NASA's Cassini spacecraft. The Cassini mission to Saturn in currently planned for launch in late 1997. Cassini will reach Saturn in 2004 and will release the Huygens probe later that year. Titan is one of only two moons in the Solar System to have an atmosphere, It has been suggested Titan might have gasoline-like lakes, and may even harbor life.
Looking Down on Saturn (1996-07-17)
This picture 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 photo was taken by the Voyager 1 spacecraft as it flew by Saturn in November 1980. The next spacecraft to approach Saturn will be Cassini which is currently scheduled to be be launched next year and reach Saturn in 2004.
Nebulosity in Sagittarius (1996-07-18)
What causes the colors in this beautiful nebulosity in Sagittarius?  Dubbed NGC 6589 and NGC 6590, the colors of this nebulosity, are caused by gas and dust. The blue color of the nebula nearest the bright stars is caused by reflection off interstellar dust. The dust emits little visible light of its own - in the absence of a nearby star the dust would appear dark, blocking light from background stars. The red color of the nebula farthest from the bright stars is caused by glowing hydrogen gas. Energetic light from the central stars ionizes hydrogen gas - which glows red when recombining with a local electron. In the absence of a nearby star, the gas would neither glow on its own nor absorb much background starlight.
Galileo's First Color Image of Io (1996-07-19)
Above is the first color image of Jupiter's volcanic moon Io released by the Galileo Project. (Io sounds like "eye-oh".) The image was made on June 25 when the Galileo spacecraft approached within 1.4 million miles. It reveals features as small as 14 miles across - comparable to the resolution of the best 1979 vintage Voyager images. The Voyager flybys discovered active volcanos on Io's mottled surface and this image indicates that dramatic changes have occurred since, notably in the region of the Masubi volcano located in Io's southern hemisphere. This region, apparently covered with new deposits of sulfur and sulfur dioxide frost deposited by volcanic eruption, is seen as the pronounced white area at the bottom of the picture. While scientists continue to analyze this image and other recent Galileo data the robot spacecraft will continue to explore Jupiter's moons. Its next scheduled close encounter is set for September 6th with the moon Ganymede. Higher resolution images of Io are also expected during the ongoing mission.
20 Years Ago: Vikings on Mars (1996-07-20)
On July 20, 1976, NASA's Viking 1 lander become the first spacecraft to land on Mars, followed weeks later by its twin robot explorer, the Viking 2 lander. Operating on the Martian surface into the early 1980s, the Vikings took thousands of pictures, conducted sophisticated chemical searches for life and studied the Martian weather and geology. In the dramatically detailed image above, a field of rocks and boulders is viewed from the Viking 1 landing sight on Chryse Planitia (the Plain of Chryse). Viking 1's dusty foot pad is just visible at the lower right. The image was created by combining high resolution black and white images with lower resolution color images of the same area. NASA is planning to continue its extremely productive and well chronicled exploration of the mysterious Red Planet with the Mars Global Surveyor and the Mars Pathfinder missions. What's Mars like today?
The Eagle Soars (1996-07-21)
On July 21, 1969 Apollo 11 astronauts Neil A. Armstrong and Edwin E. "Buzz" Aldrin Jr. lifted off the lunar surface in the ascent stage of their lunar module dubbed "The Eagle" -- after becoming the first to walk on the moon. Seen here the Eagle soars towards a rendezvous with the orbiting Command Module piloted by Michael Collins. The smooth, dark mare area on the surface below is Mare Smithii located just below the equator on the extreme eastern edge of the lunar nearside. The Earth is visible hanging above the moon's western horizon.
Utopia on Mars (1996-07-22)
The Viking 2 spacecraft was launched on the Road to Utopia in September of 1975 (30 years after Bing, Dotty, and Bob). In August of 1976, after making the second successful Martian landing, Viking 2's lander began recording data used to produce this exquisitely detailed image of the Martian surface in the area of Utopia Planitia (the Plain of Utopia). Visible at the lower right are the protective shroud that covered the lander's soil collector head, ejected after the descent, along with one of the lander's dust covered footpads. Seen near the center are shallow trenches dug by the sampler arm. Mars looks red because its surface is covered with reddish iron oxide dust (rust). This dust, suspended in the thin carbon dioxide atmosphere, also filters the sunlight causing surface views to take on a reddish tinge. The Vikings made the first successful landings on Mars 20 years ago. What does Mars look like today?