Browse NASA Astronomy Picture of the Day archive by date and media: Archive Discoveries
Browse the NASA APOD archive without needing the exact date first. Filter by media type and keep moving deeper into older images and videos.
M2-9: Wings of a Butterfly Nebula
Are stars better appreciated for their art after they die? Actually, stars usually create their most artistic displays as they die. In the case of low-mass stars like our Sun and…
Aurora and Orion
Looking toward the south from low Earth orbit, the crew of the Space Shuttle Endeavor made this stunning time exposure of the Aurora Australis or southern lights in April of 1994.…
Mapping Mars
This month, the Mars Global Surveyor (MGS) spacecraft began its primary mission to the red planet. Orbiting about once every two hours at an altitude of over 200 miles,…
Messier Marathon
Gripped by an astronomical spring fever , this week many amateur stargazers embark on a Messier Marathon . The Vernal Equinox occurs Saturday, March 20, marking the first day of…
Ice Fishing for Cosmic Neutrinos
In 1996, scientists melted a hole in the bottom of the world. In fact, several holes have been melted near the South Pole , and they are now being used as astronomical…
Sigmoids Predict Solar Eruptions
On the Sun , S marks the spot. Solar explosions have been discovered to explode preferentially from regions marked with this letter. The surface of the quiet Sun is a maze of hot…
Happy Face Crater on Mars
Even Mars can put on a happy face. The Martian crater Galle has internal markings reminiscent of a smiley face symbol. Such markings were originally discovered in the late 1970s…
The Comet and the Galaxy
The Moon almost ruined this photograph. During late March and early April 1997, Comet Hale-Bopp passed nearly in front of the Andromeda Galaxy . Here the Great Comet of 1997 and…
Phobos Over Mars
Hurtling through space a mere 3,000 miles above the Martian surface , the diminutive moon Phobos (below and left of center) was imaged against the backdrop of a large shield…
Hydrogen, Helium, and the Stars of M10
Stars like the Sun use hydrogen for fuel, “burning” hydrogen into helium at their cores through nuclear fusion . But what happens when that hydrogen runs out? For a while,…
5 Million Miles From Io
Twenty years ago this month, NASA's Voyager 1 spacecraft flew past Jupiter and its moons. This sharp picture of moon Io against a background of gas giant Jupiter's diffuse…
NGC 2997 from VLT
Add another 8-meter telescope to the list of modern optical telescope giants . Kueyen achieved a first-light photograph of a bright star on March 1, ahead of schedule. The above…
The VLT Interferometric Array
The Very Large Telescope (VLT) Interferometric Array will be able to act as individual telescopes or as one huge telescope. Of the four planned VLTs in Chile , two have now…
A Jupiter-Venus Conjunction
Venus and Jupiter appeared unusually close together in the sky last month. The conjunction was easily visible to the unaided eye because Venus appears brighter than any background…
Tycho's Supernova Remnant in X-ray
How often do stars explode? By looking at external galaxies, astronomers can guess that these events, known as a supernovae , should occur about once every 30 years in a typical…
Miranda, Chevron, and Alonso
Miranda is a bizarre world which surely had a tempest uous past. The innermost of the larger Uranian moons, Miranda is almost 300 miles in diameter and was discovered in 1948 by…
M46 And NGC 2438: Young And Old
Galactic or open star clusters are relatively young. These swarms of bright stars are born near the plane of the Milky Way, but their numbers steadily dwindle as cluster members…
Ganymede Mosaic
Ganymede , one of the four Galilean moons of Jupiter, is the largest moon in the Solar System. With a diameter of 5,260 kilometers it is even larger than planets Mercury and Pluto…
Infrared Mars
Was Mars wetter and more Earth-like in its distant past? This false-color composite image of Mars is part of the mounting evidence that liquid water once did play a significant…
The Kleinmann-Low Nebula
The most active part of the Orion Nebular Cloud Complex is an area known as the Kleinmann-Low Nebula . There, a cluster of young and forming stars is embedded in a molecular cloud…
Reflection Nebula NGC 1435
Reflection nebulae reflect light from a nearby star. Many small carbon grains in the nebula reflect the light. The blue color typical of reflection nebula is caused by blue light…
Trapezium: Teardrops in My Skies
Sometimes the unexpected comes in a familiar shape. In this picture , the seemingly familiar teardrop-shaped object just right of center is actually an unusually situated disk of…
Hamlet of Oberon
What's in a name? Since 1919, the International Astronomical Union has been charged with the task of establishing “conventional” nomenclature for planets, satellites, and surface…
Dark Cloud
Ominously foreshadowing events to come, a dark cloud of obscuring dust stands out against a luminous star field in the Milky Way . Cataloged as Feitzinger and Stuwe object “1-457”…
Viewing discoveries from 21 March 1999 through 26 February 1999.