Two dead stars smashing into each other and releasing massive amounts of energy may have created all of the heavy elements such as gold found on Earth.
That's the main conclusion of Harvard-Smithsonian Center for Astrophysics (CfA) researchers who estimated such a collision and subsequent blast of energy known as a gamma-ray burst produced and ejected as much as 10 moon masses worth of heavy elements - including gold. "Quite a lot of bling!" said lead author of a paper outlining the discovery, Edo Berger of the Harvard-Smithsonian Center for Astrophysics.
The team calculates that by combining the estimated gold produced by a single short GRB with the number of such explosions that have occurred over the age of the universe, all the gold in the cosmos might have come from gamma-ray bursts, the researchers stated. Gold is rare on Earth in part because it's also rare in the universe and unlike elements like carbon or iron, it cannot be created within a star. Instead, it must be born in a more cataclysmic event.
According to Berger, a gamma-ray burst is a flash of high-energy light (gamma rays) from an extremely energetic explosion. Most are found in the distant universe. The researchers studied on particular burst, known as GRB 130603B, which, at a distance of 3.9 billion light-years from Earth, is one of the nearest bursts seen to date. Gamma-ray bursts come in two varieties - long and short - depending on how long the flash of gamma rays lasts. GRB 130603B, detected by NASA's Swift satellite on June 3rd, lasted for less than two-tenths of a second.
Although the gamma rays disappeared quickly, GRB 130603B also displayed a slowly fading glow dominated by infrared light. "Its brightness and behavior didn't match a typical "afterglow," which is created when a high-speed jet of particles slams into the surrounding environment. Instead, the glow behaved like it came from exotic radioactive elements. The neutron-rich material ejected by colliding neutron stars can generate such elements, which then undergo radioactive decay, emitting a glow that's dominated by infrared light," the researchers stated.
"We've been looking for a 'smoking gun' to link a short gamma-ray burst with a neutron star collision. The radioactive glow from GRB 130603B may be that smoking gun," said Wen-fai Fong, a graduate student at the CfA and a co-author of the paper.
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