Ganymede: Moonquake World
4.09.1995

Ganymede probably undergoes frequent ground shaking events not unlike terrestrial earthquakes. Ganymede, the largest moon of Jupiter and the Solar System, has a thick outer coating of water ice. Passing Voyager spacecraft found...

Aurora Over Wisconsin
16.11.2004

The auroral displays of the past week are being reported as some of the most beautiful in memory. In particular, impressive auroral bands fanned out over much of eastern North America after sunset on November 8.

The Lonely Neutron Star in Supernova E0102 72.3
29.09.2018

Why is this neutron star off-center? Recently a lone neutron star has been found within the debris left over from an old supernova explosion. The "lonely neutron star" in question is the blue dot at the center of the red nebula near the bottom left of E0102-72

Sedimentary Mars
15.08.2003

High-resolution imaging of an area in the Schiaparelli Basin of Mars on June 3 by the MGS Mars Orbiter camera produced this stunning example of layered formations within an old impact crater. On planet...

APOD: 2026 May 21 Б A Collision of Galaxy Clusters
20.05.2026

This big beautiful spiral shines in X-ray light. It is about 20 times larger than our Galaxy. It belongs to Abell 2029, a galaxy cluster one billion light-years away. (To see only the galaxies...

One Hundred Kilometer Terrain on Venus
7.05.2001

Even the hot and cracked surface of Venus has rolling hills. Although never actually photographed from up-close, images of the Venusian surface like that shown above have been constructed in recent years by digitally merging distant photographs with height-sensitive radar. Isolated above is a 100-kilometer wide swath inside a volcanic region known as Yavine Corona.

The Night Side of Saturn
5.07.1995

This image of Saturn was made in November 1980 by the Voyager 1 spacecraft as it flew past the ringed gas giant planet. From a spectacular vantage point, looking back toward the inner solar system, the robot spacecraft recorded this view of the night side of Saturn casting a sharp shadow across the bright rings.

NGC 604: Giant Stellar Nursery
1.11.2002

Scattered within this cavernous nebula, cataloged as NGC 604, are over 200 newly formed hot, massive, stars. At 1,500 light-years across, this expansive cloud of interstellar gas and dust is effectively a giant stellar nursery located some three million light-years distant in the spiral galaxy, M33.

Crescent Europa
24.02.2002

Although the phase of this moon might appear familiar, the moon itself might not. In fact, this crescent shows part of Jupiter's moon Europa. The passing robot spacecraft Voyager 2 captured this image in 1979.

A Tether in Space
28.03.2005

One of the greatest unrequited legends of outer space is the tether. Tethers, long strands of material, hold the promise of stabilizing satellites, generating electricity, and allowing easy transportation. Possibly the most extreme vision of the space tether is the space elevator popularized by Arthur C.