William sent in the link https://www.msn.com/en-us/news/technology/new-research-shows-most-space-rocks-crashing-into-earth-come-from-a-single-source/ar-AA1sy4SM … but see also
https://www.space.com/earth-meteorites-asteroid-families?lrh=176 … some meteorites come from the moon or Mars but the majority, they say, have an origin in a handful of asteroid break-ups – just 3 asteroids families in the Asteroid Belt. The hypothesis is that asteroids, in the past, collided with each other as in worlds in collision. Apparently.