"In these tight groups of galaxies something special is happening," said Charlton, who chose to study Stephan's Quintet, named after its discoverer in 1877, because of the unusually large amount of activity occurring within it. The researchers have been analyzing the quintet since 1994 and their "work isn't really coming into fruition until now," she said.

At least two of the members of the quintet have been involved in collisions. "It has been 20 million years since the encounter, and yet we're seeing star clusters that were born 2 million years ago," Gallagher said in a press release. A star cluster usually consists of millions of stars as opposed to the Milky Way galaxy that consist of billions. Gallagher has published her findings in the July 2001 issue of the Astronomical Journal.

When two galaxies collide, it is not the stars that crash into each other, but the gases contained in the galaxies, which compress and give birth to new stars. More than 100 star clusters and several dwarf galaxies have been created in Stephan's Quintet from this chaos. The quintet posses the "richest known harvest of dwarf galaxies born in gaseous debris," according to a Penn State press release.

There are several factors that make Stephan's Quintet interesting to astronomers.

Normally when galaxies collide they hit head on, pass through one another and finally merge into a single galaxy, creating new stars in the impact.

What makes Stephan's Quintet special is that these galaxies are traveling too fast to merge with each other. There even is evidence of a galaxy, which is no longer part of the quintet that plowed through the compact group several hundred million years ago.

Resembling a chaotic ballet, their interacting gravity is also pulling gas and stars from each other and tossing them into space. This is known as tidal debris, due to the tidal forces that ripped them into space.

In the images taken from the Hubble telescope, a prominent sweeping tail extends from one of the galaxies — a streamer of stars and gas. There is possibly as many as 15 dwarf galaxies within this tail stretching 100,000 light-years long.

"The idea that stars can form all over the place, not just in galaxies, but between galaxies" is one of the most interesting things gained from this research, Charlton said.

Compared with our galaxy, which creates about one star per year, there is an area north of the stars of the quintet named the "northern starburst region," which is suspected of creating 10 to 1,000 stars a year. This area of gas had an external trigger such as a collision with a galaxy that sets the wheels in motion.

"The importance and perhaps uniqueness of Stephan's Quintet is that it may be a local example of phenomena typical of the early universe when encounters were much more common," Gallagher said in a press release.

The quintet is about 3,000 Milky Way galaxies away or two miles away if the galaxy were equivalent to the size of HUB-Paul Robeson Cultural Center here in University Park, Gallagher said.

The astronomers were able to use the Hubble telescope because a committee within NASA accepted their proposal. Every year proposals are sent regarding the use of the telescope; those accepted also receive funding from NASA.

It is very competitive — people want to use the telescope seven times more than what is available, Gallahger said. "A lot of science you can only do from space, that's why it is oversubscribed."

Because of their research of Stephan's Quintet, the Penn State astronomers now plan to propose a very large program with the Hubble telescope to observe 20 or more similar groups, Charlton said. If successful, they would have more than a month with the telescope to further explore the idea of multiple galaxy collisions.

"Hubble is the only space telescope that can do this kind of work," Gallagher said.

When the researchers obtain their results, they plan to post them on a Web page.