Earth won’t always be fit for occupation. We know that in two billion years or so, an expanding sun will boil away our oceans, leaving our home in the universe uninhabitable—unless, that is, we haven’t already been wiped out by the Andromeda galaxy. Moreover, at least a third of the thousand mile-wide asteroids that hurtle across our orbital path will eventually crash into us, at a rate of about one every 300,000 years.
Indeed, in 1989 a far smaller asteroid, the impact of which would still have been equivalent in force to 1,000 nuclear bombs, crossed our orbit just six hours after Earth had passed.
We have many options. The National Space Society, whose more than 12,000 members are committed to establishing settlements in space, suggests that we’ll probably first go to a planet that has the resources to support life.
The first challenge is simply to escape the pull of Earth’s own gravity. “If you can get your ship into orbit, you’re halfway to anywhere,” the writer Robert Heinlein said. The space shuttle flew at around $450 million a trip, and today sending unmanned payloads into orbit will still set you back about $12,000 a pound, with much of the cost coming from the fuel burned in those first hundred miles.
When I asked Dennis Bushnell, NASA Langley’s chief scientist, about our space prospects, he responded by offering a far more sobering view. He emphasized how little we still know about the effects of cosmic radiation and zero gravity on the human body and mind, how we don’t even have spacesuits that protect against radiation. “What’s affordable is not safe; what’s safe is not affordable,” he repeated as a kind of mantra.
read more: popsci
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