Why does the moon have so many craters when Earth doesn’t have, even though Earth’s gravity is stronger and it should be the one attracting the comets?
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Earth is also covered in craters but due to atmosphere, oxygen, life, plate tectonics, etc., they’re mostly hidden.
The moon does not have an atmosphere with rain and wind, so you can see a perfect record of craters. Rain and wind, over time, erase to signs of craters on earth.
Earth has an atmosphere, and the atmosphere burns away most of the meteorites before they hit the ground, reducing the number that hit the ground. They’re not comets though, comets are not meteorites, they almost never actually strike a planet/satellite.
A, the moon and earth BOTH attract, so while the earth pulls them in faster, the moon redirects and acts as a shield to a larger proportion than its size would indicated.
B. and the big reason, weathering. we get plenty of impacts, but we have an atmosphere and weathering that wear the craters down.
Earth has a thick atmosphere. This causes two things. First, astral debris that falls to earth experiences a ton of friction on the way down that causes most to burn up and splits many others into smaller pieces. Second, the impact craters of the few meteorites that do hit earth get covered up quickly as atmospheric effects like wind and rain cause erosion and sediment deposition.
There’s actually a *massive* crater on the Yucatan peninsula in Mexico, which is thought to be where the meteorite that killed the dinosaurs landed, but you’d never know it just by looking at it. You can only see it by mapping out the rock layers.
Three reasons:
1) The atmosphere. Only the bigger rocks can punch through it to even create a crater
EDIT:1.5) Oceans. They’re 70% of the earth’s surface. If a meteorite manages to make a crater on the ocean’s floor, it goddamn earned it.
2) Erosion. Surface features on earth get worn away. Mountains get turned to sand, depressions filled sediment. A lot of craters are actually still there (like the famous dinosaur killer Chicxulub crater), but invisible to the naked eye. I guess this is also 2.5) vegetation and water.
3) Plate tectonics. A lot of craters don’t exist anymore, because the crust they were punched into doesn’t exist anymore.
The moon lacks all of those. Any feature on it’s surface will stay there.
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The earth is covered with them to they are just hard to notice. Forest grow and lakes form and erosion gets rid of most of the features. The moon doesn’t have any of these working for it so they stay there and visible
To add to other answers, we _do_ find _some_ craters on earth. They’re usually large (see: the chixculub crater, though that’s abnormally large) and overgrown with plants from the surroundings, and only the general cup shape is still present. They’re also young, as one would expect.
The Earth has just as many craters but most have been weathered away over billions of years from Earth’s activity. The Moon isn’t very geologically active and it doesn’t have an atmosphere so there’s no real way for the craters to disappear on the moon. The Earth’s atmosphere also causes meteors to burn up from the friction and causes less impacts to the surface where the moon has no atmosphere.
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