Question

What has to happen for water to move from the atmosphere back to the earth?

Answer 1

The water (vapour) has to condensate in order to return back to earth.
This process is called “Condensation”. Condensation occurs when water vapours in the atmosphere combines with one another until they are changed into liquid, which then is returned back to earth through raindrops.

Answer 2

Answer: The water cycle! The water cycle transports water in vapor form into the atmosphere using evaporation, and then back down to the earth using condensation and precipitation.