Cluster Crash Illuminates Dark Matter Conundrum
20.08.2007

Huge clusters of galaxies are surely colliding in Abell 520 but astrophysicists aren't sure why the dark matter is becoming separated from the normal matter. The dark matter in the above multi-wavelength image is shown in false blue, determined by carefully detailing how the cluster distorts light emitted by more distant galaxies.

A MACHO View of Galactic Dark Matter
1.02.1996

What is our Galaxy made of? Stellar motions indicate there is much more mass than just stars and gas. Photographs like the two shown above may be yielding a clue about the dark matter, however.

Infrared Uranus
20.10.1998

The Sun's third largest planet usually looks quite dull. Uranus typically appears as a featureless small spot in a small telescope or a featureless large orb in a large telescope. Last August, however...

Prometheus, Pandora and Saturn's F Ring
22.12.1995

The third and fourth innermost moons of Saturn were unexpectedly discovered to be gravitational "shepards." The inner moon Prometheus and the outer moon Pandora use their gravitational attraction to define Saturn's outermost ring.

Weak Lensing Distorts the Universe
29.03.2008

Is the distant universe really what it appears to be? Astronomers hope not. Intervening dark matter, which is normally invisible, might show its presence by distorting images originating in the distant universe, much the way an old window distorts images originating on the other side.

Saturns Rings Seen Sideways
18.10.1998

Saturn's rings are actually very thin. This picture from the Hubble Space Telescope was taken on August 6, 1995 when the rings lined up sideways as seen from Earth. Saturn's largest moon Titan is seen on the left, and Titan's shadow can be seen on Saturn's cloud tops!

The Galactic Ring of NGC 6782
20.11.2001

Do spiral galaxies look the same in every color? NGC 6782 demonstrates colorfully that they do not. In visible light, NGC 6782 appears to be a normal spiral galaxy with a bright bar across its center.

Hot Gas and Dark Matter
4.04.1999

Is the gravity of the galaxies seen in this image high enough to contain the glowing hot gas? Superposed on an optical picture of a group of galaxies is an image taken in X-ray light.

The Sudbury Neutrino Detector
23.06.1999

Two thousand meters below the ground, a giant sphere has begun to detect nearly invisible particles. These particles, neutrinos, are extremely abundant in the universe but usually go right through just about everything.

HR 4796A: Not Saturn
4.02.1999

These are not false-color renderings of the latest observations of Saturn's magnificent rings. Instead, the panels show a strikingly similar system on a much larger scale - a ring around the young, Vega-like star, HR 4796A, located about 200 light-years from Earth.