[Mountain_Skies]

If that were the case, perhaps someday we will find evidence on the Moon or elsewhere in the Solar System that an earlier civilization achieved space flight before they were erased from Earth and unable to establish a permanent foothold elsewhere in our corner of the cosmos. The Moon and other celestial bodies in the Solar System of course have their own processes that erase the surface over time, but at least with the Moon, it does appear to be a far slower process.