Recently I was looking at a map of known impact structures and I noticed that they are concentrated between the tropical and arctic latitudes, but there is very little near the equator. I can think of a couple reasons that describe some features of the map, like how the Canadian Shield is ancient, has a lot of water, and lacks dense vegetation, which makes craters easy to spot. Perhaps the crust near the equator is younger and just doesn't hold as long a record, but I am not a geologist so I'm just speculating. It could also be that some physical argument like the conservation of angular momentum (i.e. which might cause a bias in trajectory deflections) and/or the distribution of asteroid orbits and their relative alignment with Earth's equatorial plane would be sufficient to explain this, but I'm curious if anyone knows of a better theory?
1$\begingroup$ this question might have an answer over at astronomy.stackexchange.com $\endgroup$– trond hansenDec 11, 2022 at 9:03
$\begingroup$ I agree, is there a way to cross-link questions across multiple stack exchange sites? $\endgroup$– chrysaor4Dec 15, 2022 at 22:17
$\begingroup$ You might find this interesting: What explains the distribution of new impact craters on Mars?. $\endgroup$– FredDec 25, 2022 at 6:27
One thing to consider is, currently, there is very little above ocean land mass around the equator. The bulk of the land mass lies above the tropic of Cancer in the northern hemisphere.
The other thing to consider is plate tectonics. Apart from Antarctica, most of the land masses have moved over time, spending various amounts of time at various latitudes and the craters that do exist may not have been created where the land masses are currently located, they may been created when the land mass was elsewhere. With plate tectonics there is also the matter of crustal renewal & recycling.
Regarding the Sahara and Namib desserts there may be craters covered by deep sand.
The map you link to in your question is a very interesting map. It would be even more interesting to have a similar series of maps for the different geological ages of Earth with the craters created on each land mass during each of those ages to see where the land masses were when they were hit.
$\begingroup$ The movement of the landmasses is a good point, and a map with the continents backtracked to their rough positions in the past would probably show interesting correlations in the crater positions - maybe it would even help with positioning their ancient locations if mutliple craters were thought to have formed from the same event? $\endgroup$ Dec 15, 2022 at 22:20