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.
Comanche Outcrop on Mars Indicates Hospitable Past
Could life once have survived on Mars? Today, neither animal nor plant life from Earth could survive for very long on Mars because at least one key ingredient -- liquid water --…
The Local Fluff
The stars are not alone. In the disk of our Milky Way Galaxy about 10 percent of visible matter is in the form of gas, called the interstellar medium (ISM). The ISM is not uniform…
Hole in the Sun
This ominous, dark shape sprawling across the face of the Sun is a coronal hole -- a low density region extending above the surface where the solar magnetic field opens freely…
Brighter Than Mars
Even though you may have just read an email claiming Mars will be incredibly bright tonight, the brightest star on the horizon is not Mars. From central Iran on August 24th, the…
M27: Not a Comet
While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were definitely not comets.…
HD 10180: Richest Yet Planetary System Discovered
Do other rich planetary systems exist? Our Solar System has the most planets of any known star, most probably because it is so hard to detect planets around other stars. Sensitive…
Galaxy Cluster Abell 1689 Magnifies the Dark Universe
What's the matter with this cluster of galaxies? To find out what forms matter takes in the Abell 1689 cluster requires not only deep images from telescopes like the Hubble Space…
A Milky Way Shadow at Loch Ard Gorge
Have you ever seen the Milky Way's glow create shadows? To do so, conditions need to be just right. First and foremost, the sky must be relatively clear of clouds so that the long…
Hoag's Object: A Strange Ring Galaxy
Is this one galaxy or two? This question came to light in 1950 when astronomer Art Hoag chanced upon this unusual extragalactic object . On the outside is a ring dominated by…
Perseid Storm
Storms on the distant horizon and comet dust raining through the heavens above are combined in this alluring nightscape . The scene was recorded in the early hours of August 13…
NGC 1365: Majestic Island Universe
Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the chemical constellation…
Pelican Nebula Close-up
The prominent ridge of emission featured in this vivid skyscape is designated IC 5067 . Part of a larger emission nebula with a distinctive shape, popularly called The Pelican…
Crescent Moon and Planets Over Portugal
Sometimes, it's fun to share the sky. Although it might appear that the two sky enthusiasts on the ridge are sharing only a crescent moon between them, three bright planets also…
NGC 4755: A Jewel Box of Stars
The great variety of star colors in this open cluster underlies its name: The Jewel Box . One of the bright central stars is a red supergiant , in contrast to the many blue stars…
Meteors Over Quebec
Meteors streaked through the sky above many of Earth's cities last week, but nobody was hurt, and no damage has been reported. The assault from space appeared to originate from…
Layered Hills in Arabia Terra on Mars
Why are some hills on Mars so layered? The answer is still under investigation. Clearly, dark windblown sand surrounds outcropping of light sedimentary rock across the floor of…
Night of the Perseids
On the night of August 12, from moonset until dawn was a good time to see meteors. Enthusiasts watched as comet dust rained on planet Earth, streaking through dark skies during…
Arp 286: Trio in Virgo
A remarkable telescopic composition in yellow and blue, this scene features a trio of interacting galaxies almost 90 million light-years away, toward the constellation Virgo . On…
Perseid Prelude
Each August, as planet Earth swings through dust trailing along the orbit of periodic comet Swift-Tuttle , skygazers can enjoy the Perseid Meteor Shower . The shower should build…
Crepuscular Rays Over Lake Michigan
What could cause such rays of dark? Dark sky rays were caught in spectacular fashion earlier last month from Pentwater , Michigan , USA , looking west over Lake Michigan . The…
The Sand Dunes of Titan
Why do some sand dunes on Titan appear backwards? Central Titan , it turns out, is covered by sand , some of which appears strange. Images from the Cassini spacecraft currently…
IRAS 05437+2502: An Enigmatic Star Cloud from Hubble
What's lighting up nebula IRAS 05437+2502? No one is sure. Particularly enigmatic is the bright upside-down V that defines the upper edge of this floating mountain of interstellar…
Two Hours Before Neptune
Two hours before closest approach to Neptune in 1989, the Voyager 2 robot spacecraft snapped this picture . Clearly visible for the first time were long light-colored cirrus -type…
Rainbow at Sunset
Where is the Sun when you see a rainbow? Behind you, of course . But you can see both a rainbow and the Sun (far right) side by side in this graceful panorama recorded on July 28.…
Viewing discoveries from 30 August 2010 through 7 August 2010.