Moon-sized bodies brought gold to Earth: NASA-funded study

A NASA-funded study has found that precious metals like gold and platinum were delivered to Earth by collisions with Moon-sized planetary bodies. The simulations showed the planetesimals penetrating into the Earth's core with some particles going back into space. Scientists estimated, the collisions, which occurred before 3.8 billion years ago, contributed around 1-2.5% of Earth's present mass.