Clouds are simple enough, just a collection of ice crystals or water droplets visible to everyone. Yet they are a source of endless wonder. They appear in an infinite number of shapes and forms. Some are beautiful, some awe inspiring, and some, like the whirling funnel cloud, are terrifying. Clouds inspire artists, poets, songwriters. They have reminded astronauts, looking down from space, that Earth, a seemingly abstract orb, is a place of life and...