Why does the moon have so many craters, but earth doesn’t? Here is a puzzle for you…
An asteroid or meteor is more likely to fall toward Earth than the Moon because our planet's stronger gravity attracts more space debris (waste material is space). But we can see many thousands of craters (holes) on the Moon and we only know of about 180 on Earth!
Where did all the Earth craters go?
The main difference between the two is that Earth has processes (systems) that can erase (remove) almost all evidence of past impacts. The Moon does not. Almost all tiny dent (damage; hole) made on the Moon’s surface is going to stay there.
Three processes help Earth keep its surface crater free (without crater). The first is called erosion. Earth has weather, water, and plants. These act together to break apart (break into pieces) and wear down (break down) the ground. Eventually, erosion can break a crater down to virtually (almost) nothing. The Moon has almost no erosion, because it has no atmosphere. That means it has no wind, it has no weather, and it certainly has no plants. Almost nothing can remove marks on its surface once they are made.
The second thing is something called tectonics. Tectonics are processes that cause our planet’s surface to form new rocks, get rid of old rocks over millions of years. Because of tectonics, the surface of Earth is recycled (is used again) many times throughout its long history. As a result, very few rocks on Earth are as old as the rocks on the Moon. The Moon has not had tectonics for billions of years. That’s a lot more time for craters to form and stay put (stay where they are).
The third thing is volcanism. Volcanic flows can cover up impacts craters. This is a major way impact craters get covered up elsewhere in our solar system, but it is less important than the recycling of crust (hard outer layer) here on Earth. The Moon once (in the past) had large volcanic flows way in the past (a long time ago) that did cover up many of the bigger earlier impacts, but it has been without volcanism for around three billion years.
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