Scientists: Cataclysmic Collisions Brought Gold to Earth

About 4.5 billion years ago, cataclysmic collisions involving Earth, the moon and Mars left gold, platinum and other elements on these newly-forming worlds, a according to a new study.

The researchers argued that impactors, or objects remaining from the solar system's planet-formation phase, likely slammed into the Earth, Mars and the Moon at around the same time.

"These impactors probably represent the largest objects to hit Earth since the giant impact that formed our moon," according to William Bottke, principal investigator from the Southwest Research Institute in Boulder, Colo. "They also may be responsible for the accessible abundance of gold, platinum, palladium, and other important metals used by our society today in items ranging from jewelry to our cars' catalytic convertors."

If the report is correct, the final stages of planetary formation were chockablock with galactic fireworks. The scenario features a planetary body as colossal as Pluto colliding with the Earth after the planet had been hit by a Mars-sized object that may have moved Earth off its axis by 10 degrees. Meanwhile, Mars and the moon also suffered major, albeit smaller cosmic collisions. In the process, however, the report suggest that these collisions resulted in bringing precious elements like gold to the earth and moon, which also may have been the recipient of water.

Pretty wild, but as you might expect, not every scientist is buying the argument. planetary scientist Jay Melosh of Purdue University told National Geographic that the theory was "really speculative, and I think some of the links in this chain of speculation are quite weak."

"The problem, then, is how the impactors' cores gave up their gold and re-implanted it into the mantles of the Earth and Mars," he said. "The only way this can happen is if the metallic iron of the impactor core is oxidized"--but that would require an abundant source of oxygen, which most models of early Earth don't include.

"So what they need to provide is some mechanism for getting those elements out of the [asteroids'] cores and into the mantle of the Earth," he said. "A mechanism for that is not at all easy and very hard to understand."

To be continued. In the meantime, take a gander at some of the major craters scientists have uncovered here on Earth and its neighboring planets.