Scientists claim that objects left on the Moon can lie hundreds of years in the same condition like astronaut Charles Duke family photo. Why we don't see remains of asteroids inside or around craters? Are asteroids going destroyed on impact or go under the surface even without any residue? Why do we not see asteroids that hit Moon with a small force and remained on the surface for hundreds of years like astronaut's photo? Can craters form for other reasons? For example, from underground collapse?
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1$\begingroup$ Just a note about the Charles Duke family photo left of the Moon. The photograph is still there, but it is speculated the image on the photo may have been destroyed by solar radiation. After nearly 50 of being on the Moon, the image is now possible totally black. $\endgroup$– FredCommented Jul 3, 2019 at 9:05
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Asteroids hit the surface of the moon at speeds of about 25 km per sec, so they are mostly vaporised on impact. If a geologist inspected a crater on foot and looked hard enough, he probably would find a few relatively small fragments, particularly if the meteorite was of the iron/nickel variety. A few such fragments were recovered from the Barringer Crater in the United States. It is unlikely an impact would leave no residue at all. but the residue might be difficult to identify. When trying to visualise the impact of, say, a 100-ton meteorite, it is helpful to imagine that it turned into 100 tons of high explosive on impact.
Yes, craters can form for other reasons. Most craters on the moon are impact craters, but a small number are volcanic. Underground collapse sometimes occurs in the vicinity of volcanoes; the resulting holes are usually elongated, and are called graben. Lava tubes sometimes collapse too, leaving a long, winding valley like a river bed. These indentations are called rills. Objects left on the moon tend to survive for centuries in good condition, because there is no weather worth talking about, just solar wind (charged particles), cosmic rays and electromagnetic radiation.
