The Einstein Cross Gravitational Lens
7.02.2010

Most galaxies have a single nucleus -- does this galaxy have four? The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image. The central cloverleaf is rather light emitted from a background quasar.

Dark Matter Map
14.08.2003

The total mass within giant galaxy cluster CL0025+1654, about 4.5 billion light-years away, produces a cosmic gravitational lens -- bending light as predicted by Einstein's theory of gravity and forming detectable images of even more distant background galaxies.

A Big Black Hole Floats By
19.01.2000

A black hole glides silently through space. Is there any way to know it's there? Until last week, all objects that might be black holes in our Galaxy were part of binary star systems.

Giant Cluster Bends, Breaks Images
23.04.2000

What are those strange blue objects? Many are images of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster galaxies here appear yellow and -- together with the cluster's dark matter -- act as a gravitational lens.

Abell 2218: A Galaxy Cluster Lens
1.02.2000

Gravity can bend light. Almost all of the bright objects in this recently released Hubble Space Telescope image are galaxies in the cluster known as Abell 2218. The cluster is so massive and so compact that its gravity bends and focuses the light from galaxies that lie behind it.

Weak Lensing Distorts the Universe
15.03.2000

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.

Simulated Galaxy Cluster View
6.03.2002

Stunningly detailed, this picture is a computer simulated view of a cluster of galaxies in the distant cosmos. A large, elliptical galaxy dominates this hypothetical cluster's central region surrounded by a swarm of member galaxies.

Abell 2218: A Galaxy Cluster Lens
7.10.2001

Gravity can bend light, allowing huge clusters of galaxies to act as telescopes. Almost all of the bright objects in this released Hubble Space Telescope image are galaxies in the cluster known as Abell 2218.

Too Close to a Black Hole
10.12.2000

What would you see if you went right up to a black hole? Above are two computer generated images highlighting how strange things would look. On the left is a normal star field containing the constellation Orion. Notice the three stars of nearly equal brightness that make up Orion's Belt.

A Bulls Eye Einstein Ring
30.03.1998

Can one galaxy hide behind another? Not in the case of B1938+666. Here the foreground galaxy acts like a huge gravitational lens, pulling the light from the background object around it, keeping it visible.