Science

by Melissa Hellmann

by Michael D. Lemonick

by TIME Photo

by Stephanie Burnett

by TIME Staff

by Michael D. Lemonick

by Sam Frizell

by Jonathan D. Woods

by TIME Staff

by Melissa Hellmann

by Alexandra Sifferlin and Bryan Walsh

by Melissa Hellmann

by Dan Kedmey

by Jonathan D. Woods

by Jeffrey Kluger