While reading the recent story about the Chinese lunar rover examining a boulder at close range, I thought of an interesting question. How much would lunar boulders move over billions of years and what would be pushing them around? It seems like an appropriate model would be a very warped billiard table covered in a layer of thick sand with the boulders more or less loose on the top. The sand corresponds to lunar regolith which is a thick layer of meteorite-caused dust that covers the entire moon.
Slight vibrations shouldn't move them much because they would be nestled in that regolith. But enough occurrences of large forces say from nearby earthquakes or asteroid impacts could move them a great distance over those long periods , I guess it depends on whether the regolith rapidly absorbs the energy of the boulder or not.
It seems like a random walk computer model that one could run with modest resources once one can characterize how the forces would act on these boulders.
Distribution of boulders and boulder tracks might well inform us of how common and how big such disruptive forces are as well as the locations of any repetitive forces (say from a fault zone).
While I don't think it's likely, even the heat/freeze cycle of lunar day/night might move these things around.
The moon still gets earthquakes. But the entire moon is quiet enough and rigid enough that NASA could detect rather small meteorite impacts with the seismometers brought with the Apollo missions (apparently five were brought over). For example, the Apollo 11 seismometer measured [nasa.gov] 100-200 meteorite impacts over a three week period (including some time out of action due to lunar night).
(Score: 1) by khallow on Wednesday January 12 2022, @02:46PM
The moon still gets earthquakes. But the entire moon is quiet enough and rigid enough that NASA could detect rather small meteorite impacts with the seismometers brought with the Apollo missions (apparently five were brought over). For example, the Apollo 11 seismometer measured [nasa.gov] 100-200 meteorite impacts over a three week period (including some time out of action due to lunar night).