The planetary collisions that occurred during the formation of our Solar System brought massive amounts of metals such as gold, platinum and iridium. After the Moon was excavated on Earth, the planet continued to be bombarded from space rocks until about 3.8 billion years ago.
Researchers from the Southwest Research Institute (SwRI) and the University of Maryland (UM) in collaboration with NASA created high-resolution impact simulations that show how the great celestial bodies crashed on Earth with enough force to reach the core of the planet or bounce on the surface, in any way, changing the physical composition of the entire sphere.
Large bodies that could not become planets ended up floating through space and colliding with the planets in the early years of the Solar System. The planetesimals, which were about the size of the Moon, but not large enough to be classified as planets. Some of these collisions were vital to the way the mantle and crust of the planets formed, NASA reports.
During this period of time called "late accretion", the Earth experienced several collisions with bodies the size of the moon.
An article published by the team in the journal Nature Geoscience details a massive accretion event that occurred just after the moon formed. When it happened, plentiful amounts of metals that chemically bond to iron such as gold, platinum and iridium were planted in the mantle of the Earth, says a report from Space.com.
"According to our simulations, the late accretion mass delivered to Earth may be significantly greater than previously thought, with important consequences for the earliest evolution of our planet," said Simone Marchi of SwRI.
These collisions caused an addition of approximately 0.5 percent of the matter to the total mass of the Earth, and much of it was carried to the Earth's core, notes the report. The material that did not reach the core, possibly was thrown back into space, whether it does not settle on the mantle.
"We modeled massive collisions and how metals and silicates were integrated into the Earth during this late stage of accretion," which lasted hundreds of millions of years after the formation of the Moon, "explains Marchi.
"Based on our simulations, the late accretion mass delivered to Earth may be significantly greater than previously thought, with important consequences for the earliest evolution of our planet," Marchi said.