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.
Hubble Resolves Expiration Date For Green Cheese Moon
Using the new camera on the Hubble Space Telescope , astronomers have been able to confirm that the Moon is made of green cheese . The telling clue was the resolution of a marked…
Solar Eclipse and SOHO
Neither rain, nor snow, nor dark of night can keep the space-based SOlar Heliospheric Observatory (SOHO) from watching the Sun . In fact, from its vantage point 1.5 million…
When Diamonds Aren't Forever
The track of totality for the first solar eclipse of 2006 began early yesterday on the east coast of Brazil and ended half a world away at sunset in western Mongolia . In between,…
Green and Black Aurora Over Norway
What causes gaps between aurora curtains? These unusual gaps can make auroral displays appear more detailed and intricate. Research using data from four Cluster spacecraft…
Animation of Asteroids Passing Near Earth
How often does an asteroid whiz by the Earth? The above time-lapse animation follows the orbit of the Earth around the Sun for two months in 2002 as numerous asteroids , also…
Moonquakes Surprisingly Common
Why are there so many moonquakes? A recent reanalysis of seismometers left on the moon by the Apollo moon landings has revealed a surprising number of moonquakes occurring within…
Doomed Star Eta Carinae
Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae 's mass - about 100 times greater than our Sun…
Northern Spring on Mars
Astronomical spring came to planet Earth's northern hemisphere this week (and autumn to the south) with the equinox on March 20th. But on Mars , northern spring began on January…
When Roses Aren't Red
Not all roses are red of course, but they can still be very pretty. Likewise, the beautiful Rosette Nebula and other star forming regions are often shown in astronomical images…
Inflating the Universe
The Universe is expanding gradually now. But its initial expansion was almost impossibly rapid as it likely grew from quantum scale fluctuations in a trillionth of a second . In…
Enceladus Near Saturn
Some images of Saturn appear surreal. Earlier this year, the robot spacecraft Cassini now orbiting Saturn took this surreal image of the gas giant Saturn , its majestic rings ,…
The Coma Cluster of Galaxies
Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies .…
Super-Earths May Circle Other Stars
Are “super-Earths” common around other star systems? Quite possibly. Unexpected evidence for this came to light recently when a planet orbiting a distant star gravitationally…
Our Busy Solar System
Our Solar System is a busy place. Although the major planets get the most press, a swarm of rocks, comets, and asteroids also exist. The above plot shows the placement of known…
Red Spot Jr.
Jupiter's Great Red Spot is a swirling storm seen for over 300 years, since the beginning of telescopic observations of the Solar System's ruling gas giant . But over the last…
The Big Dipper Cluster
A well-known asterism in northern skies, The Big Dipper is easy to recognize even when viewed upside down. Part of the larger constellation of Ursa Major , the bright dipper stars…
Eta and Keyhole in the Carina Nebula
South is toward the top in this colorful close-up view of the Great Carina Nebula (NGC 3372), famous star-forming region of the southern sky. Covering an area surrounding the…
McCool Hill on Mars
You can make it. Winter is rapidly advancing on the southern hemisphere on Mars , and the lack of sunlight could be dangerous unless you find a good place to hibernate . There it…
CG4: A Ruptured Cometary Globule
Can a gas cloud eat a galaxy? It's not even close. The odd looking “creature” in the center of the above photo is a gas cloud known as a cometary globule . This globule, however,…
Z Machine Sets Unexpected Earth Temperature Record
Why is this plasma so hot? Physicists aren't sure. What is known for sure is that the Z Machine running at Sandia National Laboratories created a plasma that was unexpectedly hot.…
Globular Cluster M3 from WIYN
This huge ball of stars predates our Sun. Long before humankind evolved, before dinosaurs roamed , and even before our Earth existed, ancient globs of stars condensed and orbited…
Colors of Comet Pojmanski
Comet Pojmanski flew by planet Earth last weekend on a surprise trip through the inner solar system. Then an easy binocular target for morning skygazers , Pojmanski ultimately…
Enceladus and the Search for Water
Based on data from Cassini spacecraft instruments, researchers are now arguing that liquid water reservoirs exist only tens of meters below the surface of Saturn's small (500…
Trio Leo
This popular group is famous as the Leo Triplet - a gathering of three magnificent galaxies in one field of view. Crowd pleasers when imaged with even modest telescopes, these…
Viewing discoveries from 1 April 2006 through 9 March 2006.