A MACHO View of Galactic Dark Matter
2.02.1996

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.

Weak Lensing Distorts the Universe
30.03.2008

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.

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.

MACSJ0025: Two Giant Galaxy Clusters Collide
17.09.2008

What happens when two of the largest objects in the universe collide? No one was quite sure, but the answer is giving clues to the nature of mysterious dark matter. In the case of MACSJ0025.

QSO H1821 643 Indicates a Universe Filled with Hydrogen
16.05.2000

A quasar slightly depleted of a specific color of light may indicate that our universe is filled with massive amounts of ionized hydrogen. Light from QSO H1821+643, pictured above, comes to us from about a quarter of the way across the visible universe.

Finding Dark Matter
19.12.2001

Where is dark matter? Galaxies rotate and move in clusters as if a tremendous amount of unseen matter is present. But does dark matter exist in the greater universe too -- and if so, where? The answer can be found by comparing the distribution of galaxies observed with numerical simulations.