A team of international researchers has discovered that the vast majority of the asteroids that collide with Earth come from just three families of asteroids, which can all be traced back to a cataclysmic event approximately 40 million years ago.

A new paper that has been published in the scientific journal Astronomy and Astrophysics, along with two other papers recently published in Nature, outlines that 70% of all known meteorites, asteroids that make it to the surface of Earth, come from the following asteroid families: Karin, Koronos, and Massalia. These families were formed approximately at different times, such as Karin five million years ago, Koronos at seven million, and Massalia at forty million. Notably, Massalia was the source for 37% of all known meteorites.
These asteroid families formed in our solar system's main asteroid belt, which is located some 700 million miles from Earth. As for the meteorites discovered on Earth, cataclysmic events caused by collisions with other asteroids within the asteroid belt resulted in fragments of asteroids being scattered into the solar system. Researchers used simulations to rewind the clock on some of the discovered meteorites and found the source of their origin.
Up until now, only 6% of known meteorites have had their origin discovered, and according to the researchers behind the study, the origin of all known meteorites is now at 90%.