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.
The Shadow Of Phobos
Hurtling through space above the Red Planet , potato-shaped Phobos completes an orbit of Mars in less than eight hours. In fact, since its orbital period is shorter than the…
Gamma-Ray Bursting
Using graphics and data from NASA's Compton Gamma Ray Observatory , this animation illustrates one of the most exciting mysteries of modern astrophysics, gamma-ray bursts .…
M32: Blue Stars in an Elliptical Galaxy
Elliptical galaxies are known for their old, red stars. But is this old elliptical up to new tricks? In recent years, the centers of elliptical galaxies have been found to emit…
Aurora Through a Moonlit Sky
A night sky can glow in fascinating ways. Through a clearing in the woods, the pictured sky above Alaska shines by reflected light from a nearby city, by the brightness of the…
The Rotten Egg Planetary Nebula
Not all evolving stars eject gas clouds that look like people. OH231.8+4.2 was a star much like our Sun that ran out of nuclear fuel to fuse in its core. It has therefore entered…
The Cat's Eye Nebula
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…
Mars Rocks, Sojourner Rolls
This sharp color image featuring Mars rock Yogi and the rolling Sojourner robot shows off Yogi's two-toned surface. Yogi appears to be leaning into the prevailing winds causing…
The USNO Millennium Time Ball
In the nineteenth century , dropping a time ball from a prominent location was a practical way of communicating the time to the surrounding country side and ships at sea .…
X-Ray Jet From Centaurus A
Spanning over 25,000 light-years, comparable to the distance from the Sun to the center of our own Milky Way galaxy, a cosmic jet seen in X-rays blasts from the center of…
In the Heart of the Tarantula Nebula
In the heart of monstrous Tarantula Nebula lies one of the most unusual star clusters. Known as NGC 2070 or R136 , it is home to a great number of hot young stars. The energetic…
30 Doradus: The Tarantula Nebula
30 Doradus is an immense star forming region in a nearby galaxy known as the Large Magellanic Cloud . Its spidery appearance is responsible for its popular name, the Tarantula…
Neptune in Infrared
Neptune has never looked so clear in infrared light. Neptune is the eighth most distant planet from the Sun, thirty times the Earth-Sun distance. Neptune is the fourth largest…
The Magnetic Carpet Of The Sun
The Sun has a magnetic carpet . Its visible surface appears to be carpeted with tens of thousands of magnetic north and south poles joined by looping field lines which extend…
M27: Not A Comet
While searching the skies above 18th century France for comets, astronomer Charles Messier diligently recorded this object as number 27 on his list of things which are definitely…
Iridium 52: Not A Meteor
While hunting for meteors in the night sky above the White Mountains near Bishop, California, astrophotographer James Young instead captured this brilliant celestial apparition .…
Follow The Spots
The Sun rotates on its axis about once every 27 days. How can you tell? Just follow the sunspots . This composite picture was constructed from solar images recorded daily by the…
NGC 2261: Hubble's Variable Nebula
What causes Hubble's Variable Nebula to vary? The unusual nebula pictured above changes its appearance noticeably in just a few weeks. Discovered over 200 years ago and…
Earth's North Magnetic Pole
A magnetic compass does not point toward the true North Pole of the Earth. Rather, it more closely points toward the North Magnetic Pole of the Earth. The North Magnetic Pole is…
NGC 3603: An Active Star Cluster
NGC 3603 is home to a massive star cluster, thick dust pillars, and a star about to explode . The central open cluster contains about 2000 bright stars, each of which is much…
Black Holes in Galactic Centers
Do all galaxies have black holes at their centers? Although not even a single galaxy has yet been proven to have a central black hole , the list of candidates continues to…
Maria Mitchell Inspires a Generation
“Do not look at stars as bright spots only - try to take in the vastness of the universe.” On October 1, 1847 Maria Mitchell swept the sky with her telescope and discovered a…
Moon Crashers
On July 31, 1964, Ranger 7 crashed into the Moon. Seventeen minutes before impact it snapped this picture - the first image of the Moon ever taken by a U.S. spacecraft. Of course…
Moon Over Eugenia
Eugenia is an asteroid with a moon ! This animation was constructed from infrared discovery images of the Eugenia-moon system taken in November 1998 using the Canada-France-Hawaii…
Ozone Hole Reduced
Although a new ozone hole has formed again this year over the South Pole , this time it is a little bit smaller than the year before . Ozone is important because it shields us…
Viewing discoveries from 5 November 1999 through 13 October 1999.