Did Earth’s Gold Come From Outer Space?

Did Earth’s Gold Come From Outer Space?
 (Top 100 Stories of 2011 #53 -DISCOVER)
Money never grows on trees, but precious metals do sometimes fall from the sky.
by Elizabeth Svoboda
DISCOVER Magazine
From the January-February special issue; published online December 27, 2011
(Image left: iStockphoto)


The platinum in your wedding 
ring and the gold in your dental fillings most likely arrived on Earth in a furious meteoric bombardment 200 million years after the planet’s formation, University of Bristol geologist Matthias Willbold reports. According to standard planetary formation models, the gold, platinum, and 
tungsten that were present when Earth was born should have quickly bonded to iron and sunk into the planet’s core. Those precious metals are thousands of times more prevalent on the surface of Earth and in its mantle than the models predict.


Willbold proposes that a colossal meteor shower about 4 billion years ago deposited the additional bling. To test his theory, he measured the isotopic mix of tungsten in rocks from an ancient formation that predates the proposed meteor shower. He then compared the readings with isotopes found in more recent rocks. “If you look at really ancient rocks in Greenland, the tungsten composition is different,” he says.


[Related Fact]
The largest gold deposit ever, may not even be on this planet. Eros, one of the closest asteroids to Earth, is thought to have gold valued in excess of a thousand billion dollars. That`s 200,000 times the amount of gold that has ever been mines on Earth.
Source: Gold Rush Alaska (Aired: 02/13/12)