Listen to the radio story with Neil deGrasse Tyson, director of New York City’s Hayden Planetarium here.
“Ever wonder where the gold in your wedding ring came from? This Valentine’s Day, we ask Neil deGrasse Tyson, director of New York City’s Hayden Planetarium, to explain the history of the rare element.
In the Beginning
According to Tyson, author of Death by Black Hole and Other Cosmic Quandries, all gold on Earth started out in the center of a star; he says stars are “in the business of cosmic alchemy.”
When the universe began, there were only two kinds of atoms: hydrogen, which has one proton, and helium, which has two protons.
The problem was that hydrogen and helium couldn’t combine to make a new kind of atom of three, four or five protons. The two atoms resisted each other because they were the same charge.
Unless, of course, it got very, very hot. How much heat would it take to get two protons to sit together?
About 10 million degrees, Tyson says. And that’s where stars come in.
Stars like our sun are so hot that protons collide with such force and have no choice but to combine. It’s called fusion. Inside the sun’s furnace, protons turn into heavier and heavier atoms: Hydrogen atoms combine to become helium, and then those helium atoms combine to become carbon.
“It keeps going,” Tyson says. “Carbon and oxygen and nitrogen and silicon, and [fusion] just plows its way up the periodic table of elements.”
Carbon has six protons, nitrogen seven protons, oxygen eight protons. A hot star can cook all the way up to iron, a 26-proton atom. But that’s where it stops.
“When you reach iron, nobody can do anything… It’s dead matter. You can’t fusion it. You can’t fission i”,” Tyson explains.
Once a star has converted all its atoms into iron, it’s out of fuel.
“That’s a bad day for the star,” Tyson says. “And at that moment, the entire star collapses, and in that collapse, the star reaches stratospheric t
Article By Robert Krulwich