Philip Ball writes:

Who said this? “I’ve been having to say everywhere I go that there is no planet B, there is no escape hatch, there is no second Earth; this is the only planet we have.” If you’re a science fiction fan the answer might surprise you: it was the writer Kim Stanley Robinson, whose Mars trilogy is an ultimately utopian series of tales that describe the terraforming of Mars – planetary engineering to give it an Earth-like environment – over the course of several centuries after the Earth perishes from overpopulation and ecosystem collapse.

Robinson’s pessimism about planetary settlement seems out of step with the spirit of the times. Unveiling his Blue Moon project two weeks ago – a robotic lunar lander to deliver the infrastructure for a crewed moon base – Amazon’s chief executive, Jeff Bezos, portrayed it as the bold first step towards human colonisation of the solar system.

That vision is endorsed by physicist and science populariser Brian Cox in his forthcoming BBC series The Planets, in which he advocates the human settlement of Mars. “There will be Martians if we are to have a future,” he says. “At some point we will be the Martians, that’s clear to me, because we can’t stay here for ever.”

Cox is in good company. “The Earth is becoming too small for us,” wrote the late Stephen Hawking. “In the long run the human race shouldn’t have all its eggs in one basket, or on one planet.” If we’re to survive, Hawking said, “I am convinced that humans need to leave Earth”.

Why this insistence? For Hawking and Cox, the horribly real threat of environmental breakdown looms large. But there the timescales aren’t on our side. [Continue reading…]