A Supercell Thunderstorm Cloud Over Montana
29.11.2010

Is that a spaceship or a cloud? Although it may seem like an alien mothership, it's actually a impressive thunderstorm cloud called a supercell. Such colossal storm systems center on mesocyclones -- rotating updrafts that can span several kilometers and deliver torrential rain and high winds including tornadoes.

Rhea: Saturn's Second Largest Moon
8.06.2003

Rhea is the second largest moon of Saturn, behind Titan, and the largest without an atmosphere. It is composed mostly of water ice, but has a small rocky core. Rhea's rotation and orbit are locked together (just like Earth's Moon) so that one side always faces Saturn.

Rhea: Saturn's Second Largest Moon
13.10.1995

Rhea is the second largest moon of Saturn, behind Titan, and the largest without an atmosphere. It is composed mostly of water ice, but has a small rocky core. Rhea's rotation and orbit are locked together (just like Earth's Moon) so that one side always faces Saturn.

NGC 1365: A Nearby Barred Spiral Galaxy
13.04.2003

Many spiral galaxies have bars across their centers. Even our own Milky Way Galaxy is thought to have a bar, but perhaps not so prominent as the one in NGC 1365, shown above. The persistence and motion of the bar imply relatively massive spiral arms.

Venus Through Water Drops
26.01.2017

Now the brilliant "star" in planet Earth's evening skies, Venus is captured in this creative astrophotograph. Taken with a close-focusing lens on January 18 from Milton Keynes, UK, it shows multiple images of the sky above the western horizon shortly after sunset.

Jupiter's Auroras
18.10.1996

Auroras are especially large on Jupiter. In pictures released yesterday, the Hubble Space Telescope imaged these unusual light displays in more detail than ever before. Jupiter's auroras are linked to its volcanic moon Io.

A Setting Sun Trail
29.07.2002

The Sun appears to move on the sky because the Earth rotates. The extreme brightness of the Sun, however, makes it difficult to capture a sun-trail -- the path the Sun traces on the sky.

Teide Sky Trails
11.02.2010

The snow capped Teide volcano is reflected in a pool of water in this nearly symmetric night sky view from the Canary Island Tenerife. Bright north star Polaris stands above the peak in an exposure that also captures the brilliant trail of a polar orbiting Iridium satellite.

NGC 1365: A Nearby Barred Spiral Galaxy
24.06.1999

Many spiral galaxies have bars across their centers. Even our own Milky Way Galaxy is thought to have a bar, but perhaps not so prominent as the one in NGC 1365, shown above. The persistence and motion of the bar imply relatively massive spiral arms.

Starburst Galaxy M94
20.11.2002

What could cause the center of M94 to be so bright? Spiral galaxy M94 has a ring of newly formed stars surrounding its nucleus, giving it not only an unusual appearance but also a strong interior glow.