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.
Warped Spiral Galaxy ESO510-13
How did spiral galaxy ESO510-13 get bent out-of-shape? The disks of many spirals are thin and flat , but not solid. Spiral disks are loose conglomerations of billions of stars and…
Molecular Cloud Barnard 68
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…
Polar Ring Galaxy NGC 4650A
NGC 4650A appears to be two galaxies in one. A rare type of galaxy known as a Polar Ring , NGC 4650A is composed of an old central group of stars and a young ring of stars…
Fractal Interstellar Dust Up-Close
Our universe is a very dusty place. Dust usually shows its presence by blocking out light emitted from stars or nebulae behind it, sometimes creating the illusion of a horse's…
Moon Occults Saturn
On September 18, 1997, many stargazers in the U. S. were able to watch a lovely early morning lunar occultation as a bright Moon passed in front of Saturn. Using a 1.2 meter…
Hot Stars in the Southern Milky Way
Hot blue stars, red glowing hydrogen gas, and dark, obscuring dust clouds are strewn through this dramatic region of the Milky Way in the southern constellation of Ara (the Altar)…
Liberty Bell 7
Today, the space capsule Liberty Bell 7 rests about 3 miles below the surface of the Atlantic Ocean. But on July 21, 1961 , astronaut Virgil I. “Gus” Grissom rode this tiny craft…
A Solar System Portrait
As the Voyager 1 spacecraft headed out of our Solar System , it looked back and took a parting family portrait of the Sun and planets. From beyond Pluto , our Solar System looks…
Magnetic Mars
Mapping Mars from orbit, instruments on the Mars Global Surveyor (MGS) spacecraft have recently revealed banded magnetic field patterns - a startling and unanticipated suggestion…
Loop I in the Northern Sky
One of the largest coherent structures on the sky is known simply as Loop I and can best be seen in radio and X-ray maps. Spanning over 100 degrees, part of Loop I appears so…
Stars from Eagle's Eggs
Newborn stars are forming in the Eagle Nebula. This image , taken with the Hubble Space Telescope in 1995, shows evaporating gaseous globules (EGGs) emerging from pillars of…
Lunar Dust and Duct Tape
Why is the Moon dusty ? On Earth, rocks are weathered by wind and water, creating soil and sand. On the Moon, the long history of micrometeorite bombardment has blasted away at…
Solar Shock Wave
On September 24, 1997 a shock wave blasted across the surface of the sun at speeds of 250 to 600 kilometers per second . On planet Earth, observer Barry Reynolds photographed the…
NGC 2266: Old Cluster in the New General Catalog
The New General Catalog of star clusters and nebulae really isn't so new. In fact, it was published in 1888 - an attempt by J. L. E. Dreyer to consolidate the work of astronomers…
A Sundial for Mars
When Mars Surveyor arrives at Mars in 2002, it will carry a sundial. Even though batteries and a solar array will power the Mars Surveyor Lander , the sundial has been included to…
Introducing Comet Lee
Another large snowball is falling toward the Sun. Comet Lee was discovered two weeks ago by Steve Lee ( AAO ) in Australia , and is expected to brighten as it approaches the inner…
USNO-A2.0 Catalog: A Digital Sky
Here lie 526,230,881 of the brightest stars known. The US Naval Observatory has deployed their monster Precision Measuring Machine to digitize photographic plates covering the…
Mimas: Small Moon with a Big Crater
Mimas is one of the smaller moons of Saturn but shows one of the largest impact craters. In fact, if the impact had been much greater, it would have disrupted the entire satellite…
Barsoom
“Yes, I have been to Barsoom again ...” begins John Carter in Edgar Rice Burroughs' 1913 science fiction classic “The Gods of Mars” . In Burroughs' novels describing Carter's…
Io Shadow
Orbiting Jupiter once every 43 hours, the volcanic moon Io cruises 500,000 kilometers above swirling, banded cloud-tops. Orbiting Earth once every 1.5 hours, the Hubble Space…
Where is Upsilon Andromedae?
Astronomers recently announced the detection of three large planets orbiting the star Upsilon Andromedae - the first planetary system known to orbit a normal star other than our…
The Nearest Stars
Which stars are closest to the Sun? The closest is Proxima Centauri , one of three stars that orbit each other about 4 light-years away in the Alpha-Centauri system. Alpha…
Candidates for a Hypernova
What created these huge explosion remnants? Speculation has been building recently that outbursts even more powerful than well-known supernovae might occur. Dubbed hypernovae ,…
The Full Moon
Earth has one moon. A symbol in famous love songs , movies , poems , and folklore , many myths about the Moon date back to ancient history. In fact, the name Monday originates…
Viewing discoveries from 12 May 1999 through 19 April 1999.