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Comment by mykowebhn | Hacker News Reader

Why do some areas have relatively few craters? I'm assuming it can't be due to erosion.

if you have 2000 small craters in an area from 100000 years ago, and then one big crater obliterates all that 1000 years ago - do you have relatively few craters?

Your explanation makes sense to me for some of the relatively smooth areas, especially the ones that are generally circular.

I don't think it adequately explains those smooth areas that are not so circular, especially if you claim that these smooth areas are due to craters formed quite recently.

ok I went and investigated https://www.iop.org/explore-physics/moon/surface-features-mo... evidently the areas that appear to be smooth to us from far away were covered by lava relatively late in moon's evolution and also have lots of craters as well, we just don't see them as well as we see the other areas that were not covered and took maybe more damage.

Oh man, thanks for this! (Something I should've done myself!)

Really interesting. Yeah, the crater patterns that I saw seemed a little too complex to be explained simply.

Also, my naive self would've assumed that the spatial distribution of meteor impacts would be uniform, but apparently this doesn't appear to be the case.

in statistics true random distribution is a smell anyway.

Actually, the cartoon infographic from that article offers a short and to the point explanation: "Giant impacts created oceans of molten rock that formed the dark maria" ("Maria" being the plural of sea in Latin) - so the craters that were there before were actually molten, and any craters that can be seen were formed later and are therefore fewer than in older regions.

Why are most of the craters relatively the same depth? Wouldn't we expect at least some to have done massive damage?

Perhaps because the same part of the moon always faces the earth which 'shields' the moon somewhat?

Just a guess

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