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.

ESO202-G23: Merging Galaxies
1.01.1999

ESO202-G

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.

NGC 1316: After Galaxies Collide
2.09.2008

Astronomers turn detectives when trying to figure out the cause of startling sights like NGC 1316. Their investigation indicates that NGC 1316 is an enormous elliptical galaxy that started, about 100 million years ago, to devour a smaller spiral galaxy neighbor, NGC 1317, just above it.

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.

NGC 4676: When Mice Collide
6.05.2002

These two galaxies are pulling each other apart. Known as "The Mice" because they have such long tails, each spiral galaxy has likely already passed through the other and will probably collide again and again until they coalesce.

The Colliding Galaxies of NGC 520
12.09.2005

Is this one galaxy or two? The jumble of stars, gas, and dust that is NGC 520 is now thought to incorporate the remains of two separate galaxies. A combination of observations and simulations indicate the NGC 520 is actually the collision of two disk galaxies.

Disorder in Stephan's Quintet
10.01.1998

What are five closely grouped galaxies doing in this image? The grouping is commonly known as Stephan's Quintet. Four of the galaxies show essentially the same redshift suggesting that they are at the same distance from us.