Science writer John Emsley said, that the gold came from outer space that falls to Earth via meteorite. The Native Americans thought that the precious element is believed to come from another world or extraterrestrial.
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| The idea that gold came from outer space sounds like science fiction, but it has become well-established - it's pretty much received opinion in the field of earth sciences. How did this bizarre theory take hold, and is it here to stay? (Picture from: http://www.bbc.co.uk/) |
"Why do you find the nuggets of gold on the surface of the Earth? The answer was they have arrived here from outer space in the form of meteorites," said John. This theory came last decades that are held by the majority of scientists as a way to explain the abundance of gold on the Earth.
The experts suspect that there are only 1.3 grams of gold per 1,000 tons of other material in the Earth's crust. However, the alleged 1.3 grams is considered more when adjusted for the planet formation model. Scientists explain, after its birth four-and-a-half billion years ago, the surface of the Earth heaved with volcanoes and molten rock. Then, over tens of millions of years, most of the iron sank down through the outer layer, known as the mantle, to the Earth's core. Gold would have mixed with the iron and sunk with it.
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| The formation of Earth. (Picture from: http://www.bbc.co.uk/) |
Matthias Willbold, a geologist at Imperial College London, likens the process to droplets of vinegar collecting at the bottom of a dish of olive oil. "The theory is after the core formed, there is a meteor that hit the Earth. Meteorite contains a number of gold and fill the Earth's mantle and the continental crust with gold," said Willbold as reported by the BBC. He also said that a great meteor shower events have occurred on Earth over 3.8 billion years ago. This meteorite hitting the planet's surface and creating a crater as seen on the Moon's surface today.
This idea of the gold-laden-meteorite "veneer" was first proposed following the Apollo moon landings of the 1970s. Scientists examining rock samples from the moon's mantle found much less iridium and gold than they did in samples from the surface of the moon or from the earth's crust and mantle. It was proposed that the moon and Earth had been battered by iridium-rich meteorites, known as chondrites, from outer space. While the precious fallout from this meteoric shower lay scattered on the surface of the moon, on Earth the planet's internal activity had churned it into the mantle too.
The idea, called the "late veneer hypothesis", has become a fundamental theory in planetary science. It also helps to explain many other anomalies in the Earth's composition - it is thought that the same meteorites delivered the carbon, nitrogen, water and the amino acids that are vital to all life on the planet. *** [EKA | FROM VARIOUS SOURCES | BBC | SEPTI | PIKIRAN RAKYAT 10102013]
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