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 Dark River to Antares
Connecting the Pipe Nebula to the bright star Antares is a flowing dark cloud nicknamed the Dark River . The murkiness of the Dark River is caused by absorption of background…
Contemplating the Sky
Have you contemplated your sky recently? This week will be a good one for midnight meditators at many northerly locations as meteors from the Perseid meteor shower will frequently…
Giant Cluster Bends, Breaks Images
What are those strange blue objects? Many are images of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster…
The Giant and the Glory
On a flight from Vienna to Brussels, astronomer Franz Kerschbaum looked out the window and photographed this beautiful atmospheric phenomenon, the glory , shining in the direction…
Emission Nebula IC 1396
Sprawling across hundreds of light-years, emission nebula IC 1396 mixes glowing cosmic gas and dark dust clouds . Stars are forming in this area, only about 3,000 light-years from…
Solar Arcs and Halos
Have you ever seen a bright halo around the Sun? Unusual halos and arcs were so bright one recent afternoon in Trier , Germany that even casual people on the street noticed them.…
Shadow of a Martian Robot
What if you saw your shadow on Mars and it wasn't human ? Then you might be the Opportunity rover currently exploring Mars. Opportunity and sister robot Spirit have been probing…
Spicules: Jets on the Sun
Imagine a pipe as wide as a state and as long as half the Earth. Now imagine that this pipe is filled with hot gas moving 50,000 kilometers per hour. Further imagine that this…
A Force from Empty Space: The Casimir Effect
This tiny ball provides evidence that the universe will expand forever. Measuring slightly over one tenth of a millimeter, the ball moves toward a smooth plate in response to…
Tonight: A Blue Moon
How often does a full moon occur twice in a single month? Exactly once in a Blue Moon . In fact, the modern usage of the term “Blue Moon” refers to the second Full Moon in a…
Northern Lights
While enjoying the spaceweather on a gorgeous summer evening in mid-July, astronomer Philippe Moussette captured this colorful fish-eye lens view looking north from the…
Melas Chasma
Steep cliffs drop into the rugged terrain of Melas Chasma in this stunning view from the Mars Express spacecraft orbiting the Red Planet. At a scale of 16 meters per pixel, the…
A Cygnus Starfield
In the constellation of the swan near the nebula of the pelican lies the gas cloud of the butterfly surrounding a star known as the hen . That star, given the proper name Sadr ,…
Razorbacks in Endurance Crater
Over one year after its launch, robot geologist Opportunity has been spending recent sols on Mars inching its way down the slopes of Endurance crater . Littered with martian…
A Large Active Region Crosses the Sun
An unexpectedly large sunspot region is now crossing the Sun. The active region is home to rivers of hot plasma , explosive flares , strong magnetic fields , a powerful Coronal…
A Solar Filament Lifts Off
Hot gas frequently erupts from the Sun. One such eruption produced the glowing filament pictured above , which was captured in 2000 July by the Earth-orbiting TRACE satellite .…
A String Of Pearls
Comet Shoemaker-Levy 9 , named after its co-discoverers , was often referred to as the “string of pearls” comet. It is famous for its suggestive appearance as well as its…
Saturn's Rings in Natural Color
What colors are Saturn's rings? Recent images from the Cassini spacecraft now orbiting Saturn confirm that different rings have slightly different colors. The above image shows…
Aura Launch
In this alluring time exposure, star trails arc across the night sky above Monterey Bay and the lights of Santa Cruz, California, USA. But since the exposure began around 3:01am…
A Shadow on the Rings of Saturn
This picture of Saturn could not have been taken from Earth. No Earth based picture could possibly view the night side of Saturn and the corresponding shadow cast across Saturn's…
Space Station, Venus, Sun
On June 8, Venus was not the only celestial object to pass in front of the Sun. A few well-situated photographers caught the International Space Station also crossing the Sun…
Attacking Mars
The Spirit rover attacked Mars again late last month. What might look, above, like a military attack, though, was once again just a scientific one - Spirit was instructed to…
M31: The Andromeda Galaxy
Andromeda is the nearest major galaxy to our own Milky Way Galaxy . Our Galaxy is thought to look much like Andromeda . Together these two galaxies dominate the Local Group of…
Transit of Venus Stereogram
Venus glides in front of an enormous solar disk in these two frames from the TRACE satellite imaging of the inner planet's 2004 transit . Arranged in a “right/left” stereogram,…
Viewing discoveries from 9 August 2004 through 17 July 2004.