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.
Comet Garradd Passes Ten Thousand Stars
Comet Garradd continues to brighten as it drifts across the northern sky. Last week the comet, visible with binoculars and discernible by its green coma , passed nearly in front…
Herschel Views the Milky Way
With a 3.5 meter diameter mirror, larger than the Hubble Space Telescope, ESA's Herschel Space Observatory explores the Universe at infrared wavelengths. Herschel is named for…
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.…
Roll Cloud Over Wisconsin
What kind of cloud is this? A type of arcus cloud called a roll cloud . These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing…
The Coldest Brown Dwarf
This cosmic snapshot composed with image data from NASA's Wide-field Infrared Survey Explorer ( WISE ) satellite captures a multitude of faint stars and distant galaxies toward…
Hickson 44 in Leo
Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies , now appropriately called Hickson Compact Groups .…
A Jet from Galaxy M87
What's causing a huge jet to emanate from the center of galaxy M87 ? Although the unusual jet was first noticed early in the twentieth century , the exact cause is still debated.…
Hurricane Irene Forms
How does a hurricane form? Although a complete picture is still being researched, insight into this process might be gleaned by watching the above time lapse movie of the…
A Young Supernova in the Nearby Pinwheel Galaxy
A nearby star has exploded and telescopes all over the world are turning to monitor it. The supernova, dubbed PTF 11kly, was discovered by computer only two days ago as part of…
Portrait of NGC 281
Look through the cosmic cloud cataloged as NGC 281 and it's almost easy to miss stars of open cluster IC 1590 . But, formed within the nebula , that cluster's young, massive stars…
A Pileus Iridescent Cloud Over Ethiopia
Yes, but how many dark clouds have a multicolored lining? Pictured, behind this darker cloud, is a pileus iridescent cloud , a group of water droplets that have a uniformly…
Aurora Over Greenland
This aurora arched from horizon to horizon. During the current Shelios expedition to observe and learn about the northern lights, the sky last weekend did not disappoint. After…
TrES-2b: Dark Planet
Why is this planet so dark? Planet TrES-2b reflects back less than one percent of the light it receives, making it darker than any known planet or moon, darker even than coal .…
The Fairy of Eagle Nebula
The dust sculptures of the Eagle Nebula are evaporating. As powerful starlight whittles away these cool cosmic mountains , the statuesque pillars that remain might be imagined as…
Stereo Vesta
Get out your red/blue glasses and float next to 4 Vesta. A 500 kilometer diameter world, Vesta lies in the main asteroid belt between the orbits of Mars and Jupiter. This stereo…
Herschel's Cocoon
In this remarkable infrared skyscape of interstellar clouds adrift in the high flying constellation Cygnus, the eye is drawn to the Cocoon Nebula . Also known as IC5146, the dusty…
A Sun Pillar Over Ontario
What is that on the horizon? No, it's not an alien starship battling distant Earthlings, but rather a sun pillar. When driving across Ontario , Canada in early June, the…
Perseid Below
Denizens of planet Earth watched this year's Perseid meteor shower by looking up into the moonlit night sky . But this remarkable view captured by astronaut Ron Garan looks down…
Shapley 1: An Annular Planetary Nebula
What happens when a star runs out of nuclear fuel ? For stars about the mass of our Sun, the center condenses into a white dwarf while the outer atmospheric layers are expelled…
Rover Arrives at Endeavour Crater on Mars
What can the present-day terrain in and around large Endeavour crater tell us about ancient Mars? Starting three years ago, NASA sent a coffee-table sized robot named Opportunity…
Tornado and Rainbow Over Kansas
The scene might have been considered serene if it weren't for the tornado . During 2004 in Kansas , storm chaser Eric Nguyen photographed this budding twister in a different light…
Castle and Meteor by Moonlight
Each August, as planet Earth swings through dust trailing along the orbit of periodic comet Swift-Tuttle , skygazers enjoy the Perseid Meteor Shower . As Earth moves through the…
NGC 7331 and Beyond
Big, beautiful spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way . About 50 million light-years distant in the northern constellation Pegasus , NGC 7331 was…
The Snows of Paranal
Recorded last week, this dawn portrait of snowy mountain and starry sky captures a very rare scenario. The view does feature a pristine sky above the 2,600 meter high mountain…
Viewing discoveries from 3 September 2011 through 11 August 2011.