Lifeboat Foundation

Maybe they’re not alien doppelgangers — mirror images of us.

But extraterrestrial life—should it exist—might look “eerily similar to the life we see on Earth,” says Charles Cockell, professor of astrobiology at the University of Edinburgh in Scotland.

Indeed, Cockell’s new book (The Equations of Life: How Physics Shapes Evolution, Basic Books, 352 pages) suggests a “universal biology.” Alien adaptations, significantly resembling terrestrial life—from humanoids to hummingbirds—may have emerged on billions of worlds.