Does the moon attract meteorites that otherwise would have hit the earth?
There are surely many objects that strike the moon which would otherwise have struck the Earth. There are other objects whose trajectory is changed enough by the gravity of the moon that they miss Earth. There are also many objects whose trajectory is influenced by the gravity of the moon so that they do hit Earth (or burn up in its atmosphere). It would be difficult to prove that any benefit to the Earth comes because the moon “attracts” incoming objects rather than because the moon “intercepts” them (i.e. gets in the way). I can imagine different mechanisms, but calculating the overall net effect of the mechanics might take a while. My instinctive inclination is that the net effect of the moon “attracting” things is close to neutral – the gravity of the moon causing just as many hits as misses. [Technically, the moon “attracts” everything that gets close to Earth – that is how gravity works…
The most famous impact event that affected Earth is perhaps the Chicxulub impact event, which has been linked to the extinction of the dinosaurs 65 million years ago. It is, however, only one of many impact events that have affected our planet and not even one of the largest. The record of these processes is very poor on Earth, because our planet has a lot of geologic processes that destroy or mask evidence of impact events. Mountain building processes crumple impact craters, plate subduction consumes impact craters, erosion dissects impact craters, and lava flows and sediments often bury any remaining impact craters. While scientists continue to discover a handful of impact craters each year, the number of known craters is quite small (currently ~160; see Map for a current listing of impact craters). A much better record of the impact cratering history of the Earth is preserved on our neighboring Moon. Because water does not flow across its surface, lava no longer erupts from its volc
The moon doesn’t “attract” the meteorites. The gravity of the earth beats that of the moon so the earth will pull the meteorites more towards itself than the moon can pull them away. It might however pull them slightly off course, but this won’t be by any large amount. The real defence of the moon is it’s large size in comparison to the object is orbits (this is the smallest planet/moon ratio in the solar system). This makes it like a big shield so more likely to be in the path of the meteorite that is heading for us. You can see this is obviously the case by the huge scars on the moon that have never healed (been eroded by the atmosphere as they are on earth). This is quite a good point to bring up as by using crater densities you can tell the age of the moon since it was volanic. This is because the dark maria’s (seas) have a lower crater density than the whiter material. By comparing the two, you can get an estimate of when this occured (the cooling of these seas) in the moons life.
