Browse NASA Astronomy Picture of the Day archive by date and media: Archive Discoveries
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NGC 6210: The “Turtle in Space” Planetary Nebula
A Turtle in Space? Planetary nebula NGC 6210 may look like a giant space turtle, but it is actually much more massive and violent. Fortunately, this gas cloud in Hercules lies…
Henrietta Leavitt Calibrates the Stars
Humanity's understanding of the relative brightness and variability of stars was revolutionized by the work of Henrietta Swan Leavitt (1868-1921). Working at Harvard College…
An Ion Drive for Deep Space 1
Space travel entered the age of the ion drive Saturday with the launch of Deep Space 1 , a NASA mission designed primarily to test new technologies. Deep Space 1 is bound for…
The Pleiades Star Cluster
It is the most famous star cluster on the sky. The Pleiades can be seen without binoculars from even the depths of a light-polluted city . Also known as the Seven Sisters and M45…
The Sun Also Rises
Sunrise seen from low Earth orbit by the shuttle astronauts can be very dramatic indeed ( and the authors apologize to Hemingway for using his title!). In this breathtaking view,…
Seyfert Galaxy NGC 7742
This might resemble a fried egg you've had for breakfast , but it's actually much larger. In fact, ringed by blue-tinted star forming regions and faintly visible spiral arms , the…
Jupiter: When Storms Collide
Sometime in February , two of three long-lived Jovian storm systems known as “white ovals” apparently collided and merged -- forming what is now likely the second largest storm in…
The Case of the Missing Aurora
Sometimes, near midnight, auroras suddenly stop . Nobody knows why. This nightside gap in aurora was confirmed recently by D. Chua ( U. Washington ) and colleagues in data from…
Infrared Uranus
The Sun 's third largest planet usually looks quite dull. Uranus typically appears as a featureless small spot in a small telescope or a featureless large orb in a large…
Olympus Mons from Orbit
Olympus Mons on Mars is the largest volcano in the Solar System . Although three times higher than Earth's Mount Everest , Olympus Mons would not be difficult to climb because of…
Saturn's Rings Seen Sideways
Saturn's rings are actually very thin. This picture from the Hubble Space Telescope was taken on August 6, 1995 when the rings lined up sideways as seen from Earth . Saturn 's…
A Giant Globular Cluster in M31
This cluster of stars, known as G1, is the brightest globular cluster in the whole Local Group of galaxies. Also called Mayall II, it orbits the center of the largest nearby…
Io Aurora
Alluring aurora surrounding Io (eye-oh) appear as a ghostly glow while the volcanic moon orbits within Jupiter's dark shadow. Gas giant Jupiter is off to the right of this image,…
A Great Day For SOHO
The last 10 days have been great days for SOHO , the space-based SOlar and Heliospheric Observatory. Contact was completely lost with this international research spacecraft over 3…
The World's Largest Ozone Hole
It's back, and it's bigger than ever. The ozone hole that has been a cause of concern in recent years has again reformed over Earth's South Pole . The seasonal recurrence of the…
In the Center of the Dumbbell Nebula
Here's part of the Dumbbell Nebula that you can't see through binoculars . To see this, we suggest a sophisticated spectrograph attached to a telescope with an 8-meter aperture.…
The Hubble Deep Field in Infrared
Galaxies this faint have never been seen before. In 1996 the Hubble Space Telescope (HST) created one of the most famous pictures of modern astronomy, the Hubble Deep Field (HDF).…
Resolving Mira
Most stars appear only as points of light. Early last year, Betelgeuse became the second star, after our Sun , to have it surface resolved. Later last year, Mira was added to the…
Maria Mitchell Inspires a Generation
“Do not look at stars as bright spots only - try to take in the vastness of the universe.” October 1st was the 151st anniversary of the day Maria Mitchell swept the sky with her…
M27: Not A Comet
While searching the skies above 18th century France for comets, astronomer Charles Messier diligently recorded this object as number 27 on his list of things which are definitely…
Far Side of the Moon
Locked in synchronous rotation, the Moon always presents its well-known near side to Earth. But from lunar orbit, Apollo astronauts also grew to know the Moon's far side. This…
Ocean Planet Pole To Pole
The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument onboard the orbiting SeaStar spacecraft can map subtle differences in Earth's ocean color . These North (left) and…
Comet Williams in 1998
The brightest comet in the sky right now is Comet Williams . Moving slowly though the constellation of Centaurus , Comet Williams, at magnitude 8, is visible to Southern…
A Sunspot Up Close
Sometimes, small regions of the Sun appear unusually dark. Visible above is a close-up picture of a sunspot , a depression on the Sun's face that is slightly cooler and less…
Viewing discoveries from 28 October 1998 through 5 October 1998.