Mercury: A Cratered Inferno
12.09.2004

Mercury's surface looks similar to our Moon's. Each is heavily cratered and made of rock. Mercury's diameter is about 4800 km, while the Moon's is slightly less at about 3500 km (compared with about 12,700 km for the Earth). But Mercury is unique in many ways.

Messier 5
9.05.2019

"Beautiful Nebula discovered between the Balance [Libra] & the Serpent [Serpens] ..." begins the description of the 5th entry in 18th century astronomer Charles Messier's famous catalog of nebulae and star clusters. Though it appeared...

APOD: 2023 September 3 Б Comet Schwassmann Wachmann 3 Fragments
3.09.2023

Periodic comet 73P/Schwassmann-Wachmann 3 has broken up at least twice. A cosmic souffle of ice and dust left over from the early solar system, this comet was first seen to split into several large pieces during the close-in part of its orbit in 1995.

The Earth-Moon System
29.01.1998

This evocative mosaic image of the Earth-Moon system was recorded by NASA's Near Earth Asteroid Rendezvous (NEAR) spacecraft earlier this month. The relative sizes shown are appropriate for viewing both the Earth...

Ring Around the Galaxy
23.12.1998

It is difficult to hide one galaxy far behind another. The closer galaxy's gravity will act like a huge lens, pulling images of the background galaxy around both sides. This is just...

APOD: 2006 January 1- The Largest Rock in the Solar System
1.01.2006

There, that faint dot in the center - that's the largest rock known in our Solar System. It is larger than every known asteroid, moon, and comet nucleus. It is larger than any other local rocky planet.

Stardust in Aries
9.12.2017

This composition in stardust covers over 8 degrees on the northern sky. The mosaicked field of view is west of the familiar Pleiades star cluster, toward the zodiacal constellation Aries and the plane of our Milky Way Galaxy.

APOD: 2025 September 8 Б IRAS 04302: Butterfly Disk Planet Formation
8.09.2025

This butterfly can hatch planets. The nebula fanning out from the star IRAS 04302+2247 may look like the wings of a butterfly, while the vertical brown stripe down the center may look like the butterfly's body -- but together they indicate an active planet-forming system.

Centaurus A: The Galaxy Deep Inside
2.02.2002

Deep inside Centaurus A, the closest active galaxy to Earth, lies ... another galaxy! Cen A is a giant elliptical galaxy a mere 10 million light-years distant with a central jumble of stars, dust, and gas that probably hides a massive black hole.

The Cracked Ice Plains of Europa
22.10.1996

What caused the cracks in this giant ice-ball? Jupiter's moon Europa has smoothest surface in the solar system and is composed mostly of cracked water-ice. In the above false-colored picture released last week...