Helios Helium
20.05.1996

Above is an image of the relatively quiet Sun made on May 18 in light emitted by ionized Helium atoms in the Solar chromosphere. Helium was first discovered in the Sun in 1868, its name fittingly derived from from the Greek word Helios, meaning Sun. Credit for the discovery goes to astronomer Joseph Lockyer.

Sher 25: A Pending Supernova?
12.08.1997

No supernova has ever been predicted - yet. These dramatic stellar explosions that destroy stars, that create and disperse the elements that compose people and planets, that light up the night sky, are not so well understood that astronomers can accurately predict when a star will explode - yet. Perhaps Sher 25 will be the first.

Aurora Oklahoma
13.11.2003

Nestled in the central US, the state of Oklahoma is noted for its gorgeous prairie skies and wide-open spaces, but not for frequent visitations of the northern lights. Still, following the intense solar activity...

Cratered Cliffs of Ice on Saturns Tethys
12.10.2005

The surface of Saturn's moon Tethys is riddled with icy cliffs and craters. The most detailed images ever taken of Tethys were captured late last month as the robot Cassini spacecraft swooped past the frozen ice moon.

Pantheon Earth and Moon
20.04.2007

Could this be a picture of the Earth and Moon from space? It certainly looks like it at first glance, with a dark, cratered Moon standing off from planet Earth's lovely blue disk surrounded by a nurturing atmosphere. In fact, this view looks up into the dome of the ancient Pantheon in Rome.

I Zwicky 18: The Case of the Aging Galaxy
17.10.2007

How old is this galaxy? The galaxy on the left, I Zwicky 18, was once thought to be one of the youngest galaxies on record since its bright stars indicated an age of only 500 million years.

The Belt of Venus Over Mercedes Argentina
7.02.2012

Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink or orange.

South Polar Vortex Discovered on Titan
24.07.2012

What's happening over the south pole of Titan? A vortex of haze appears to be forming, although no one is sure why. The above natural-color image shows the light-colored feature. The vortex was found on images taken last month when the robotic Cassini spacecraft flew by the unusual atmosphere-shrouded moon of Saturn.

Milky Way and Exploding Meteor
12.08.2015

Tonight the Perseid Meteor Shower reaches its maximum. Grains of icy rock will streak across the sky as they evaporate during entry into Earth's atmosphere. These grains were shed from Comet Swift-Tuttle.

The Horsehead Nebula
16.12.2015

The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the dark indentation to the red emission nebula in the center of the above photograph. The horse-head feature is dark because it is really an opaque dust cloud that lies in front of the bright red emission nebula.