APOD: 2025 July 30 Б Coronal Loops on the Sun
30.07.2025

Our Sun frequently erupts in loops. Hot solar plasma jumps off the Sun's surface into prominences, with the most common type of prominence being a simple loop. The loop shape originates from the Sun's magnetic field, which is traced by spiraling electrons and protons.

APOD: 2024 November 12 Б NGC 6888: The Crescent Nebula
12.11.2024

How was the Crescent Nebula created? Looking like an emerging space cocoon, the Crescent Nebula, visible in the center of the featured image, was created by the brightest star in its center. A leading progenitor hypothesis has the Crescent Nebula beginning to form about 250,000 years ago.

The Backyard Universe
14.04.1999

How far can you see from your own backyard? Across the Solar System, even across our Galaxy, these sights are not difficult. Recently, however, amateur Paul Boltwood gazed across the universe. His record setting image is shown above in false color.

An Airplane Glory
22.12.2016

Looking out the window of an airplane, you might be lucky enough to see "the glory" in the direction directly opposite the Sun. Before airplanes, the phenomenon, known to some as the heiligenschein or the Specter of the Brocken, was sometimes seen from mountaintops.

Colliding Supernova Remnants
2.10.1997

When a massive star exhausts its nuclear fuel it explodes. This stellar detonation, a supernova, propels vast amounts of starstuff outwards, initially at millions of miles per hour. For another 100,000 years...

Comet Hale-Bopp and the Dumbbell Nebula
20.02.1997

Comet Hale-Bopp is now slowly moving across the morning sky. During its trip to our inner Solar System, the comet passes in front of several notable objects. Here Comet Hale-Bopp was photographed on February 11th superposed nearly in front of the picturesque Dumbbell Nebula, visible on the upper right.

The Heart and Soul Nebulas
14.09.2008

Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible in the above zoomable view on the right, has a shape reminiscent of a classical heart symbol.

A Roll Cloud Over Uruguay
5.01.2010

What kind of cloud is this? A roll cloud. These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a cloud.

Saturns Hyperion: A Moon with Odd Craters
27.02.2011

What lies at the bottom of Hyperion's strange craters? Nobody's sure. To help find out, the robot Cassini spacecraft now orbiting Saturn swooped past the sponge-textured moon in 2005 and 2010 and took images of unprecedented detail.

A Huge Solar Filament Erupts
15.12.2010

Click the arrow and watch an unusually long filament explode out from the Sun. The filament had been seen hovering over the Sun's surface for over a week before it erupted earlier this month.