Cosmic pile-up spied in space
Artist's image of four-galaxy merger
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Tuesday, 07, Aug 2007 04:48
A colossal cosmic pile-up between four galaxies has been captured by Nasa's Spitzer telescope.
Astronomers predict the galaxies will eventually merge into one vast galaxy about ten times the size of our own Milky Way.
Writing in Astrophysical Journal Letters, scientists say this sighting will provide unprecedented information about how the most massive galaxies in the universe form.
The new quadruple merger is occurring in a distant cluster of galaxies known as CL0958+4702 nearly five billion light years away.
Three of the galaxies are about the size of the Milky Way while the fourth one is much larger.
As they merge they are flinging billions of older stars, half of which will later fall back into the galaxies.
The plume of light created by these stars was what first drew the attention of Nasa's Spitzer telescope and the WIYN telescope.
"Most of the galaxy mergers we already knew about are like compact cars crashing together," said Kenneth Rines of the Harvard-Smithsonian Center for Astrophysics.
"What we have here is like four sand trucks smashing together, flinging sand everywhere."
Galaxy mergers are common in the universe; our Milky Way will merge with the Andromeda galaxy in five billion years.