Why do some clouds look like cotton balls while others look like flying saucers? The shapes of clouds reveal different things ...

The air around and above us always has some water vapor and some particles in it. The particles could be dust or salt or even ...

Astronomers have struggled to explain why a long and thin cloud forms above Mars’s Arsia Mons volcano each year, until now ...

Jack Knudson is an assistant editor for Discover Magazine who writes articles on space, ancient humans, animals, and sustainability, and manages the Planet Earth column of the print issue. View Full ...