Astronomers have a pretty good
understanding of where the matter in our universe comes from. In the beginning,
there was only hydrogen, helium, and a tiny smattering of lithium. Everything
else, the oxygen we breathe, the carbon that makes up so much of our bodies,
the silicon, magnesium, aluminum, and other elements that make up our planet,
were all formed inside stars and released into the wider universe when stars
explode.
But there is one element that still has astronomers bumfuzzled: gold. There is too much of it. Supernova explosions can’t begin to account for the amount that we see because the gold is trapped in the neutron stars, the remnants of supernovas. Colliding neutron stars release prodigious amounts of gold, as do so-called magneto-rotational supernova. These rare supernovas spin so fast and generate such strong magnetic fields that they literally turn themselves inside out. This releases all of their trapped gold atoms. But while both produce extraordinary quantities of gold, they are extremely rare and cannot begin to account for all the gold we find here on Earth.
Chiaki Kobayashi is an
astrophysicist at the University of Hertfordshire in the United Kingdom. She
led the new study to determine the origin of gold. "There are two stages
to this question," she said. "Number one: neutron star mergers are
not enough. Number two: Even with the second source, magneto-rotational
supernova, we still can't explain the observed amount of gold." Kobayashi
and the other study authors accounted for the formation and relative abundance of
all elements from carbon to uranium. All except for gold. Its abundance remains
a mystery.
So, the next time you put on that
gold ring or necklace, you can marvel that our Earth has as much gold as it
does.
