The term "descended" means the act of falling, coming down from a higher place to a lower place. It is the act of coming down from a higher grown to a lower grown.
In H. G. Wells's "The War of the Worlds", the narrator/ speaker uses the term <em>"fall/ fallen" </em>multiple times in the given excerpt. The speaker describes the fallen mass <em>"from outer space"</em> which people thought must be another meteorite. And that was also why people did not go looking for it, for no one thought or expected it to be an alien ship.
