HI4PI: The Hydrogen Sky
24.10.2016

Where are the Milky Way's gas clouds and where are they going? To help answer this question, a new highest-resolution map of the sky in the universe's most abundant gas -- hydrogen -- has been completed and recently released, along with its underlying data.

The Magellanic Stream
15.08.2013

In an astronomical version of the search for the source of the Nile, astronomers now have strong evidence for the origin of the Magellanic Stream. This composite image shows the long ribbon...

Star Trails Over Oregon
9.09.2009

As the Earth spins on its axis, the sky seems to rotate around us. This motion, called diurnal motion, produces the beautiful concentric trails traced by stars during time exposures. Partial-circle star trails are pictured above over Grants Pass, Oregon, USA last month.

APOD: 2025 February 4 Б Anticrepuscular Rays: A Rainbow Fan over Spain
4.02.2025

Yes, but can your rainbow do this? Late in the day, the Sun set as usual toward the west. However, on this day, the more interesting display was 180 degrees around -- toward the east. There, not only was a rainbow visible, but an impressive display of anticrepuscular rays from the rainbow's center.

Hale-Bopp: The Great Comet of 1997
8.04.2022

Only twenty-five years ago, Comet Hale-Bopp rounded the Sun and offered a dazzling spectacle in planet Earth's night skies. Digitized from the original astrophoto on 35mm color slide film, this classic image of the Great Comet of 1997 was recorded a few days after its perihelion passage on April 1, 1997.

The Milky Way's Gamma-Ray Halo
5.11.1997

Our Milky Way galaxy appears to be surrounded by a halo of gamma rays. Gamma rays are the most energetic form of electromagnetic radiation, with more than a hundred thousand times the energy of visible light, but known gamma-ray sources don't account for the diffuse distribution of this high-energy glow.

APOD: 2026 July 6 Б Dueling Bands over the Atacama Desert
6.07.2026

What are these two bands in the sky? The more commonly seen band is on the left and is the central band of our Milky Way galaxy. Our Sun orbits in the disk of this spiral galaxy so that from inside, it appears as a band of comparable brightness all the way around the sky.

The Magellanic Stream
25.01.2010

Spanning the sky toward the majestic Clouds of Magellan is an unusual stream of gas: the Magellanic Stream. The origin of this gas remains unknown but likely hold a clue to origin and fate of our Milky Way's most famous satellite galaxies: the LMC and the SMC.

A Mystery in Gamma Rays
11.08.2001

Gamma rays are the most energetic form of light, packing a million or more times the energy of visible light photons. If you could see gamma rays, the familiar skyscape of steady stars would be replaced by some of the most bizarre objects known to modern astrophysics -- and some which are unknown.

A Dark Sky Over Sequoia National Park
27.08.2009

Scroll right to take in the view from the highest summit in the contiguous USA. The above 360-degree digitally stitched panorama, taken in mid-July, shows the view from 4,400-meter high Mt. Whitney in Sequoia National Park, California. In the foreground, angular boulders populate Mt.