Galaxies are not distributed evenly through the universe. Instead, they exist in clusters and chains, and these areas with relatively high numbers of galaxies surround comparatively empty caverns in space. Scientists think gravity has caused the dense areas to become more dense over the billions of years since the Big Bang.

While the Universe at large is thought to be expanding in all directions, subtle exceptions indicate the presence of unseen concentrations of "dark matter" that contributes to all this localized intergalactic bunching.

In 1986, astronomer Alan Dressler and six other researchers found that the Milky Way and a host of neighboring galaxies are all streaming at hundreds of miles per second toward a spot in the constellation Centaurus, some 150 million light-years away. Dressler and his colleagues named this point in space the Great Attractor, and it appears to be chock full of extra galaxies and lots of dark matter.

The ESO images, released last week, show galaxies at what may be the heart of the Great Attractor, scientists said.

The enormous galaxy cluster, called ACO 3627, shows the violent forces at work when galaxies get together. Twisted shapes and remnants of previous collisions show a continual process of galactic cannibalization, researchers say.