1、The reversal takes a relatively short amount of time, geologically speaking, only a few thousand years.
3、Within about 50 million years--no time at all, geologically speaking--one of the four kings of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale.
2、Apollo astronauts used seismometers during their visits to the Moon and discovered that the gray orb isn't a totally dead place, geologically speaking.