Astronomy Picture Of the Day (APOD)Ice Halos by Moonlight
An almost full moon on April 15 brought these luminous apparitions to a northern spring night over Alberta Canada. On that night, bright moonlight refracted and reflected by hexagonal ice crystals in high clouds created a complex of halos and arcs more commonly seen by sunlight in daytime skies.
The Milky Way s Black Hole
There's a black hole at the center of the Milky Way. Stars are observed to orbit a very massive and compact object there known as Sgr A* (say "sadge-ay-star"). But this just released...
Young Stars of NGC 346
The massive stars of NGC 346 are short lived, but very energetic. The star cluster is embedded in the largest star forming region in the Small Magellanic Cloud, some 210,000 light-years distant. Their...
Gravity s Grin
Albert Einstein's general theory of relativity, published over 100 years ago, predicted the phenomenon of gravitational lensing. And that's what gives these distant galaxies such a whimsical appearance, seen through the looking glass of X-ray and optical image data from the Chandra and Hubble space telescopes.
NGC 6334: The Cats Paw Nebula
Nebulas are perhaps as famous for being identified with familiar shapes as perhaps cats are for getting into trouble. Still, no known cat could have created the vast Cat's Paw Nebula visible toward the constellation of the Scorpion (Scorpius.
A Martian Eclipse: Phobos Crosses the Sun
What's that passing in front of the Sun? It looks like a moon, but it can't be Earth's Moon, because it isn't round. It's the Martian moon Phobos. The featured video was taken from the surface of Mars a month ago by the Perseverance rover.
Spiral Galaxy NGC 1512: The Inner Rings
Most galaxies don't have any rings -- why does this galaxy have two? To begin, the bright band near NGC 1512's center is a nuclear ring, a ring that surrounds the galaxy center and glows brightly with recently formed stars.
Firefall by Moonlight
On certain dates in February, an elusive firefall can be spotted at sunset in Yosemite National Park, when water flows, the weather cooperates and the direction to the setting Sun is just right. Often...
NGC 3572 and the Southern Tadpoles
This cosmic skyscape features glowing gas and dark dust clouds along side the young stars of NGC 3572. A beautiful emission nebula and star cluster it sails far southern skies within the nautical constellation Carina.
NGC 3521: Galaxy in a Bubble
Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years away, toward the northern springtime constellation Leo. Relatively bright in planet Earth's sky, NGC 3521 is easily visible in small telescopes but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like M66 and M65.