Saturday science subject: A really old gamma ray burst

— 10:08 PM on October 31, 2009

The neat thing about light and other radio waves is that, even though they travel extremely fast by our standards, they still take billions of years to go from one end of the universe to another. So, the further away we point our telescopes, the further back in time we look—and that means we can sometimes get a glimpse of our universe's infancy

As ScienceNow reports, two teams of researchers at the University of Leicester in the UK and the Italian Institute of Astrophysics in Italy did just that earlier this year. Thanks to NASA's SWIFT satellite, the teams were able to image the most distant (and therefore oldest) object ever: the gamma ray burst from a star turning into a black hole over 13 billion years ago, just 600 million years after the Big Bang. ScienceNow has more:

Every week, astronomers sight two or three gamma ray bursts (GRBs), short flashes of high-energy radiation from collapsing stars. Most turn out to be from the nearby universe. But GRB 090423--named, by convention, after the date it was detected--shatters the previous record for farthest object, a galaxy 12.8 billion light-years away that was discovered in 2006. "It brings us close to that magical point of first light," says Volker Bromm, an astrophysicist at the University of Texas, Austin, who was not involved in the study. "We don't have to get much farther to catch the earliest stars."

Researchers are interested in spotting and studying such far-out objects because they provide a window on the early universe. Theoretical models predict that blobs of gas began collapsing into massive stars within a few hundred million years of the big bang. These stars burned for a while before exploding as supernova. The limited information obtained from GRB 090423's spectra indicates that despite its proximity to the big bang, it does not belong to the first generation of stars, the two teams report.

You can view the image for yourself here.

Perhaps we'll get to see even older objects in the future, too. ScienceNow quotes Nial Tanvir of the University of Leicester as saying the early universe had a high enough star density to allow this record to be broken. "Finding such events is not an unreasonable hope," he claims.

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