APOD: 2025 September 1 Б Callisto: Dirty Battered Iceball
1.09.2025

Its surface is the most densely cratered in the Solar System -- but what's inside? Jupiter's moon Callisto is a battered ball of dirty ice that is larger than the planet Mercury.

NGC 4631: The Whale Galaxy
29.03.2002

NGC 4631 is a big beautiful spiral galaxy seen edge-on only 25 million light-years away towards the small northern constellation Canes Venatici. This galaxy's slightly distorted wedge shape suggests to some a cosmic herring and to others the popular moniker of The Whale Galaxy.

Antennae Galaxies in Near Infrared
11.04.2002

What happens when galaxies collide? One of the best studied examples of the jumble of star clusters, gas, and dust clouds produced by such a cosmic train wreck is the interacting galaxy pair NGC 4038 / NGC 4039, the Antennae Galaxies, only sixty million light-years away.

Halo of the Cat's Eye
4.09.2002

The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this stunning false-color picture, processed...

Neutron Mars
4.09.2004

Looking for water on Mars, researchers using detectors on board the orbiting Mars Odyssey spacecraft have created this false-color global map of energetic neutrons from the otherwise Red Planet. What do neutrons have to do with water?

X Ray Stars in the Orion Nebula
19.05.2005

When our middle-aged Sun was just a few million years old it was thousands of times brighter in x-rays. In fact, it was likely similar to some of the stars found in this false-color x-ray composite of the Orion Nebula region from the Chandra Observatory.

The Giant Radio Lobes of Fornax A
28.06.2005

Together, the radio lobes span over one million light years -- what caused them? In the center is a large but peculiar elliptical galaxy dubbed NGC 1316. Detailed inspection of the NGC 1316 system indicates that it began absorbing a small neighboring galaxy about 100 million years ago.

Sandy Gas Jets Hypothesized on Mars
23.08.2006

What's causing seasonal dark spots on Mars? Every spring, strange dark spots appear near the Martian poles, and then vanish a few months later. These spots typically span 50 meters across and appear fan shaped. Recent observations made with THEMIS instrument onboard NASA's Mars Odyssey, currently orbiting Marscarbon dioxide (CO2) ice beneath them.

The Elephant s Trunk in IC 1396
26.12.2008

(xxxedit and linkxxx) Like an illustration in a galactic Just So Story, the Elephant's Trunk Nebula winds through the emission nebula and young star cluster complex IC 1396, in the high and far off constellation of Cepheus. Of course, this cosmic elephant's trunk is over 20 light-years long.

Messier 106
19.03.2011

Close to the Great Bear (Ursa Major) and surrounded by the stars of the Hunting Dogs (Canes Venatici), this celestial wonder was discovered in 1781 by the metric French astronomer Pierre Mechain. Later, it was added to the catalog of his friend and colleague Charles Messier as M106.