Scientists say gold and platinum may have come from meteorites

Earth's abundant supply of precious metals, including gold and platinum, is the result of meteorites bombarding the planet long after Earth was formed, according to researchers in the U.K.

The researches from the University of Bristol detailed their findings in an article appearing in the journal Nature.

They explained that when the Earth was formed molten iron sank to its center to make the core. During this occurrence, they said, most of the planet's precious metals were taken with it.

The Earth has enough precious metals in the core today to cover the entire surface with a 13-foot-thick layer, according to the study.

However, the metals we find along the surface of the Earth today are the result of the meteorites, they said.

"It has previously been argued that this serendipitous, over-abundance results from a cataclysmic meteorite shower that hit the Earth after the core formed. The full load of meteorite gold was thus added to the mantle alone and not lost to the deep interior," according to a news release from the university.

The researchers conducted their study by performing ultra-high precision analyses of some of the oldest rock samples on Earth, which were in Greenland. reported that the Earth's core is comprised of iron, to which metals such as gold, nickel, platinum and iridium are attracted. If the Earth first formed as a molten mass, then the outer layers of the Earth should have been stripped of its precious metals as they migrated to the core.

This study supports a theory by geologists that suggests that Earth was bombarded with meteorites between 3.8 and 4 billion years ago. This, they think, may have resulted in the shiny metals, which over time became part of the portion of the Earth between the crust and the core.

The theory is also supported by craters on the moon, which some geologists believe were also struck by meteorites around the same time as the earth, reported .

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