ATLANTA A pair of colliding galaxies is flush with the building blocks for planets and ultimately life, astronomers announced this week.
The galaxies, known as the Antennae for their appearance, are filled with the raw materials that could one day lead to habitable planets and the stars to warm them. The abundance of such enriched materials is 10 times what astronomers see in the interstellar medium.
"The amount of enrichment of elements in the Antennae is phenomenal," said Giusseppina Fabbiano, an astronomer with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, who led the study.
The concentration of metals within the Antennae should eventually coalesce to form a plethora of rocky planets, she said.
The finding was presented here this week at the 203rd meeting of the American Astronomical Society.
The Antennae galaxies sit about 60 million light-years away, so the present observations show them as they existed 60 million years ago. Some change would have occurred since then but is not apparent to earthbound astronomers. The galaxies started colliding between 500 and 700 million years ago.
"They really are the archetype for colliding galaxies," said John Hibbard, an astronomer with the National Radio Astronomy Observatory who develops computer models of the interacting galaxies.
Fabbiano and her colleagues used NASAs Chandra X-ray Observatory to detect rich deposits of heavy elements like iron, magnesium and silicon within the Antennae galaxies. These elements were most likely blown out into space by supernovas, exploding stars triggered by the violence of the galactic collision.
"There are about 30 times as many supernovas exploding in the Antennae than in our own Milky Way," Fabbiano said.
The exploding stars are the end result of huge clouds of gas slamming together as the two galaxies collide. The vastness of interstellar space makes impacts between individual stars rare. But as the clouds hit, they fuel an outbreak of baby stars, the most massive of which become supernovas and enrich the local area with heavy elements that could form planets.
"If life arises on a significant fractions of these planets, then in the future the Antennae will be teeming with [it]," said Francois Schweizer, co-author of the study and a scientist with the Carnegie Observatories in Pasadena, California. "A vast number of Sun-like stars and planetary systems will age in unison for billions of years."
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