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.
Earth at Night
This is what the Earth looks like at night. Can you find your favorite country or city ? Surprisingly, city lights make this task quite possible. Human-made lights highlight…
Solar Sail
Could solar sailing become a future Olympic sport ? Nearly 400 years ago astronomer Johannes Kepler observed comet tails blown by a solar breeze and suggested that vessels might…
Raining Perseids
Comet dust rained down on planet Earth last week, streaking through dark skies in the annual Perseid meteor shower . So, while enjoying the anticipated space weather, astronomer…
Windblown N44F
A fast and powerful wind from a hot young star has created this stunning bubble-shaped nebula poised on the end of a bright filament of hydrogen gas. Cataloged as N44F , the…
Lightning on Earth
Nobody knows what causes lightning. It is known that charges slowly separate in some clouds causing rapid electrical discharges (lightning), but how electrical charges get…
The Unusual Blueberries at Bylot Rock
Why aren't these Martian rocks round? Small rocks dubbed blueberries have been found by the Opportunity rover all over Meridiani Planum on Mars , but the ones perched on Bylot…
Close-Up of the Lagoon
Stars are battling gas and dust in the Lagoon Nebula but the photographers are winning. Also known as M8, this photogenic nebula is visible even without binoculars towards the…
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…
Messenger Launch
Streaking into the early morning sky on August 3rd, a Delta II rocket launches NASA's Messenger spacecraft on an interplanetary voyage to Mercury . Scheduled to become the first…
Perseid Fireball Over Japan
Enjoying the bright Moon's absence from early morning skies, observers around the world reported lovely displays during this year's Perseid meteor shower . As anticipated, peak…
The Spectrum of a Meteor
Chasing the brief flash of a meteor trail across the sky with a very large telescope is a nearly impossible task. But on May 12, 2002, astronomers got lucky , as a bright meteor…
A Perseid Meteor
The ongoing Perseid Meteor Shower should be at its strongest tonight and tomorrow night. Although meteors should be visible all night long, the best time to watch will be between…
The Double Haze above Titan
Most moons have no haze layer at all - why does Titan have two? Images from the Cassini spacecraft that slipped into orbit around Saturn last month confirm that the Solar System's…
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…
Viewing discoveries from 22 August 2004 through 30 July 2004.