"Dying stars billions of years ago cooked up most of the lighter elements in the universe, the oxygen in the air and calcium of our bones, and blasted it across the cosmos in their final explosive moments.
We are stardust, as the singer Joni Mitchell put it.
But some of the heaviest atoms, including gold, defied this explanation, requiring an even more exotic origin.
...gold is likely created as an aftereffect of the collision of two "neutron" stars. Neutron stars are themselves the collapsed remains of imploded stars, incredibly dense stellar objects that weigh at least 1.4 times as much as the sun but which are thought to be less than 10 miles wide.
...explosive collisions of two neutron stars happen only about once every 10,000 years. And it appears they spew out gold and other heavy elements in the week after their merger.
...Observation of the cloudy aftereffects of the burst suggest that each merger of two neutron stars produces several moons worth of gold by weight.
...In the collision, sub-atomic particles blasted out of the neutron stars fuse together to form heavy elements, escaping a black hole that forms afterward from the merger. Such are the likely origins for the gold that accumulated in Earth's crust some 4.54 billion years ago, swept up from space at the birth of the solar system..."
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