IN 1933 Bergeron1 postulated that rain falls only from clouds which contain both water drops and ice crystals. Natural cumulus clouds at temperatures above -13° C. often contain only supercooled ...

but it’s still not clear what happens far below the cloud tops. So researchers designed an experiment to compress hydrogen and helium, reaching pressures nearly 2 million times Earth’s ...

Cloud seeding is a "weather modification concept that attempts to draw more rain or snow out of a cloud ... where you can do a truly controlled experiment." Instead, experts attribute the rainfall ...