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.
Oklo: Ancient African Nuclear Reactors
The remnants of nuclear reactors nearly two billion years old were found in the 1970s in Africa. These reactors are thought to have occurred naturally. No natural reactors exist…
Star Streams and the Sunflower Galaxy
A bright spiral galaxy of the northern sky, Messier 63 is about 25 million light-years distant in the loyal constellation Canes Venatici . Also cataloged as NGC 5055, the majestic…
Vela Supernova Remnant
The plane of our Milky Way Galaxy runs through this complex and beautiful skyscape . At the northwestern edge of the constellation Vela (the Sails) the four frame mosaic is over…
Cepheus: Trunk to Bubble
Star clusters, glowing nebulae and dark dust clouds abound in Cepheus , royal constellation of the northern hemisphere. You can follow them in amazing detail across this broad…
NGC 4911: Spiral Diving into a Dense Cluster
Why are there faint rings around this spiral galaxy? Possibly because the galaxy, NGC 4911 , is being pulled at by its neighbors as it falls into the enormous Coma Cluster of…
Space Shuttle Tribute Poster: Endeavour
They are some of the most complex machines ever built. From a standing start they can launch a school - bus sized object up so high and moving so fast that it won't fall back…
A Laser Strike at the Galactic Center
Why are these people shooting a powerful laser into the center of our Galaxy? Fortunately, this is not meant to be the first step in a Galactic war . Rather, astronomers at the…
GRO J1655-40: Evidence for a Spinning Black Hole
In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole . Studies of the bright light emitted by the swirling gas…
Young Suns of NGC 7129
Young suns still lie within dusty NGC 7129 , some 3,000 light-years away toward the royal constellation Cepheus . While these stars are at a relatively tender age, only a few…
The Small Cloud of Magellan
Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two celestial…
The Bubble Nebula
Blown by the wind from a massive star, this interstellar apparition has a surprisingly familiar shape . Cataloged as NGC 7635, it is also known simply as The Bubble Nebula .…
Earth and Moon from MESSENGER
What does Earth look like from the planet Mercury? The robotic spacecraft MESSENGER found out as it looked toward the Earth during its closest approach to the Sun about three…
The Annotated Galactic Center
The sky toward the center of our Galaxy is filled with a wide variety of celestial wonders , many of which are visible from a dark location with common binoculars . Constellations…
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…
Viewing discoveries from 12 September 2010 through 20 August 2010.