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Golden Mergers

December 23, 2013

If Santa’s especially generous this year, you might find something shiny in your Christmas stocking: gold. As you admire it, think about this: that bit of soft, beautiful metal just might have been created during the birth of a black hole.

Almost all of the chemical elements are created by stars, either during their long lifetimes, or in supernovae — the explosive deaths of heavy stars. But some recent research says that some of the heaviest elements may require multiple stellar deaths.

Six months ago, an orbiting satellite detected a brief but powerful explosion known as a gamma-ray burst. It most likely was the result of the merger of two neutron stars — the corpses of once-mighty stars that had already exploded.

The collision formed a black hole. But the violent outburst that accompanied the merger blasted away some material before it could fall into the black hole. Astronomers studied the afterglow of this hot cloud.

The afterglow showed that the ejected material included some of the heaviest elements, which are difficult if not impossible to make in normal supernova outbursts. That includes a lot of gold — enough to make 10 Moons.

These kinds of mergers are rare — there’s probably only one every hundred thousand years in our own galaxy. But the researchers say that over cosmic time, they could account for all of the gold in the universe — a bounty of beauty from the birth of black holes.


Script by Damond Benningfield, Copyright 2013

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