Most of the worlds of our Solar System are pockmarked with impact craters. These bear testament to the violence of the early days of the Sun, when asteroids, comets and entire planets routinely collided with and annihilated each other.
Our own Moon was most likely formed by one of these collisions, and is itself home to the largest impact feature in the Solar System – the South Pole/Aitken Basin, some 2,500km across. Mars’ vast, flat northern deserts may too have formed during a gigantic collision some 4 billion years ago.
