Soon after the formation of Earth, our planet was hit by massive space rocks, and this clash led to the formation of the Moon. However, as the Solar System was still in formation, the planet kept getting hit by other planetary bodies until 3.8 billion years ago. Researchers studied these phenomena, and discovered that such collisions were the one that brought metals like iridium, gold, and platinum on our planet.
Many space rocks crashed into Earth during the formation of the Solar System
NASA, together with the University of Maryland and the Southwest Research Institute, developed some simulations of all these collisions. They observed how the impacts were extremely powerful, so the space rocks could penetrate our planet until they reached its core.
When they didn’t break the surface of the planet, the rocks were projected in the opposite direction. Either way, the clashes were powerful enough so that they could change the aspect and composition of Earth and its surface. This phenomenon is called late accretion.
These collisions introduced gold and platinum on Earth
When the Solar System came into being, some pieces of space rocks weren’t big enough to count as planets. Usually, they were the size of the Moon and, as they were floating around, they crashed into whatever cosmic objects stood in their way. These processes were essential for the formation of planets and of the elements present on them.
“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,” explains Simone Marchi, one of the researchers.
As the collisions took place on Earth, they added about 0.5 percent extra matter to its surface. Many of it didn’t reach the core, and remained on the outer crust. According to the simulations, this was the moment when silicates and metals were introduced on our planet.