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.
Cassini Images Density Waves in Saturn's Rings
What causes the patterns in Saturn's rings? The Cassini spacecraft just entering orbit around Saturn has started sending back spectacular images of Saturn's immense ring system in…
M57: The Ring Nebula
Except for the rings of Saturn , the Ring Nebula (M57) is probably the most famous celestial band. This planetary nebula's simple, graceful appearance is thought to be due to…
Cassini To Venus
Saturn Orbiter Cassini with Titan Probe Huygens attached rocketed into early morning skies on October 15, 1997. The mighty Titan 4B Centaur rocket is seen here across the water,…
The Encke Gap: A Moon Goes Here
Yesterday, Cassini became the first spacecraft to enter orbit around gas giant Saturn , rocketing through a 25,000 kilometer wide gap in the distant planet's magnificent system of…
NGC 7331: A Galaxy So Inclined
If our own Milky Way galaxy were 50 million light-years away with its disk inclined slightly to our line of sight, it would look a lot like large spiral galaxy NGC 7331 . In fact,…
Phoebe: Comet Moon of Saturn
Was Saturn's moon Phoebe once a comet? Images from the robotic Cassini spacecraft taken two weeks ago when entering the neighborhood of Saturn indicate that Phoebe may have…
In the Center of NGC 6559
Bright gas and dark dust permeate the space between stars in the center of a nebula known as NGC 6559 . The gas, primarily hydrogen , is responsible for the diffuse red glow of…
Spirit Rover Reaches the Columbia Hills on Mars
The Spirit robotic rover on Mars has now reached the Columbia Hills on Mars. Two of the hills are shown on approach near the beginning of June. The above true-color picture shows…
Galaxy Cluster Abell 1689 Warps Space
Two billion light-years away, galaxy cluster Abell 1689 is one of the most massive objects in the Universe. In this view from the Hubble Space Telescope's Advanced Camera for…
Neptune: Still Springtime After All These Years
In the 1960s spring came to the southern hemisphere of Neptune, the Solar System's outermost gas giant planet. Of course, since Neptune orbits the Sun once every 165 earth-years ,…
Planet Earth from SpaceShipOne
On June 21st , pilot Mike Melvill made a historic flight in the winged craft dubbed SpaceShipOne -- the first private manned mission to space. The spaceship reached an altitude of…
The Galaxy Within Centaurus A
Peering deep inside Centaurus A, the closest active galaxy to Earth, the Spitzer Space Telescope's penetrating infrared cameras recorded this startling vista . About 1,000…
A Picturesque Venus Transit
The rare transit of Venus across the face of the Sun earlier this month was one of the better-photographed events in sky history. Both scientific and artistic images have been…
Unusual Spires Found on Comet Wild 2
How did unusual spires form on comet Wild 2 ? Close inspection of images taken of Comet Wild 2 by the passing Stardust spacecraft in January show numerous strange pinnacles as…
Analemma over Ancient Nemea
An analemma is that figure-8 curve that you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. Above, 44 separate exposures (plus…
Solstice Celebration
Season's greetings! Today or tomorrow, depending on your time zone, the Sun reaches its northernmost point in planet Earth's sky marking a season change and the first solstice of…
Ida and Dactyl: Asteroid and Moon
This asteroid has a moon! The robot spacecraft Galileo destined to explore the Jovian system, encountered and photographed two asteroids during its long interplanetary voyage to…
The Trifid Nebula from Hubble
Clouds of glowing gas mingle with lanes of dark dust in the Trifid Nebula , a star forming region toward the constellation of Sagittarius . In the center, the three huge dark dust…
Comet NEAT and the Beehive Cluster
To the unaided eye, they appeared as similar fuzzy patches. But when a bright comet passed in front of a bright star cluster last month, binoculars and cameras were able to show…
Elliptical Galaxy M87
Elliptical galaxy M87 is a type of galaxy that looks much different than our own Milky Way Galaxy . Even for an elliptical galaxy , though, M87 is peculiar. M87 is much bigger…
A Rare Annular Venusian Solar Eclipse
An unusual type of solar eclipse occurred last week. Usually it is the Earth's Moon that eclipses the Sun. Last week, for the first time in over 100 years, the planet Venus took a…
Unusual Layers on Saturn's Moon Phoebe
What caused the unusual light and dark layers on Saturn 's moon Phoebe ? The layers were discovered just Friday during the Cassini spacecraft flyby of the small moon. Such…
Volcano and Aurora in Iceland
Sometimes both heaven and Earth erupt. In Iceland in 1991, the volcano Hekla erupted at the same time that auroras were visible overhead. Hekla , one of the most famous volcanoes…
NGC 4676: When Mice Collide
These two mighty galaxies are pulling each other apart. Known as “ The Mice ” because they have such long tails, each spiral galaxy has likely already passed through the other.…
Viewing discoveries from 5 July 2004 through 12 June 2004.