Artist’s concept of the lunar-forming giant impact. Image: NASA
The final stages in the growth of the planets of the inner solar system, including Earth, involved cataclysmic collisions with other large bodies. Our own Moon is thought to have formed as a result of such a “giant impact” between the proto-Earth and a Mars-sized proto-planet. While there remains significant levels of uncertainty about the size and relative velocity of the colliding bodies, it seems certain that the birth of our own planet was a less than tranquil affair!