Earth’s gold may come from gamma ray bursts

Artist's conception of two neutron stars at the moment of collision All gold in the universe likely came from massive cosmic collisions of the dead cores of stars that previously exploded as supernovas, US astronomers say.
Gold, rare on Earth in part because it's also rare in the universe, cannot be created within a star like carbon or iron, they said. Instead, it must be born in a more cataclysmic event, like one observed last month known as a short gamma-ray burst.
The GRB resulted from the collision of two neutron stars, and a unique glow that persisted for days at the GRB location likely signified the creation of substantial amounts of heavy elements including gold, a release from the Harvard-Smithsonian Centre for Astrophysics said Wednesday.
"We estimate that the amount of gold produced and ejected during the merger of the two neutron stars may be as large as 10 moon masses - quite a lot of bling!" lead author Edo Berger said.
A gamma-ray burst is a flash of high-energy light from an extremely energetic explosion, and while most occur in the distant universe, Berger and his colleagues were able to study GRB 130603B at a distance of 3.9 billion light-years from Earth, one of the nearest bursts seen to date.
After the initial explosion, GRB 130603B displayed a slowly fading glow dominated by infrared light that behaved like it came from exotic radioactive elements, which undergo radioactive decay to become heavy elements including gold.
The astronomers said 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 suggests all the gold in the cosmos might have come from gamma-ray bursts.
"To paraphrase Carl Sagan, we are all star stuff, and our jewellery is colliding-star stuff," Berger said.
Source: UPI