The Debunker: Would You Really Explode In Space?

by Ken Jennings


As NASA’s Curiosity rover continues to inch across the red planet’s dusty Gale Crater, America’s interest in space exploration inches upward as well. Jeopardy!’s Ken Jennings is a bit of space nerd himself, and this month he’ll be navigating us through an asteroid belt of misconceptions about the exploration of the cosmos. Even if you’re not one of the 6 percent of Americans who believes that the moon landing was a hoax, you might have been fleeced by one or more of these fallacies about the final frontier.

Space Myth #4: People Exposed to the Vacuum of Space Would Explode.

It’s not something most of us will probably ever have to face, but still we wonder: what would happen to an unprotected person in the vacuum of space? Knowing what happens to deep-sea divers in similar situations, you’d be forgiven for believing the sci-fi version of this scenario: the unfortunate space traveler swells up in agony like Arnold Schwarzenegger in Total Recall and eventually blows up like that poor guy in Outland.

Well, worry no longer. NASA says that primate experiments—and one accidental human trial in 1965 involving a vacuum test chamber and a leaky spacesuit!—confirm its scientists’ predictions on this point. You won’t explode. Your skin is sturdy enough to keep you together despite the pressure differential. Your ears might suffer a bit, you could sunburn, and your sweat and saliva will boil away, but you’ll probably avoid any permanent effects for thirty seconds or so…as long as you (counter-intuitively) remember not to hold your breath, which will mess up your lungs.

You’ll probably pass out from oxygen deprivation in about fifteen seconds, which means you’ll miss the nastier long-term effects (frostbite, swelling, asphyxiation). But NASA’s guess is that it would take a minute or two for space to kill you. In other words, the Total Recall/Outland model is incorrect and the 2001/Hitchhiker’s Guide version is closer to the truth: you’ll have 30 seconds or so to get back inside the spaceship the next time you’re menaced by HAL 9000 or a Vogon constructor fleet. I hope that helps you sleep easier tonight.

Quick Quiz: What space-phobic physician grumbled incorrectly in a 2009 film, “One tiny crack in the hull and our blood boils in thirteen seconds”?

Ken Jennings is the author of Because I Said So!, Brainiac, Ken Jennings's Trivia Almanac, and Maphead. He's also the proud owner of an underwhelming Bag o' Crap. Follow him at or on Twitter as @KenJennings.