Stephen Hawking is making apocalyptic predictions again. The respected theoretical physicist warns that humanity needs to become a multi-planetary specieswithin the next century if we don’t want to go extinct. Last year, he prophesied that we had maybe 1,000 years left on Earth, and the inspiration for this newly-urgent timeline is unclear—except for the fact that Hawking’s new documentary about colonizing Mars is coming out soon.

To be sure, Earth is facing some big problems, including climate change, overpopulation, epidemics, and asteroid strikes. But before we flee this planet like an action hero jumping out of an explosion, let’s think about this for a second. Sure, it’d be great to have a backup civilization somewhere in…