COLLES ANGLAIS

TEXTE 15

For life, not for an afterlife Seeking to make Earth expendable is not a good reason to settle other planets Oct 1st 2016 | THE ECONOMIST MARS has been much possessed by death. In the late 19th century Percival Lowell, an American astronomer, persuaded much of the public that the red planet was dying of desertification. H.G. Wells, in “The War of the Worlds”, imagined Martian invaders bringing death to Earth; in “The Martian Chronicles” Ray Bradbury pictured humans living among Martian ghosts seeing Earth destroyed in a nuclear spasm. Science was not much cheerier than science fiction: space probes revealed that having once been warmer and wetter, Mars is now cold, cratered and all-but-airless. Perhaps that is why the dream of taking new life to Mars is such a stirring one. Elon Musk, an entrepreneur, has built a rocket company, SpaceX, from scratch in order to make this dream come true. On September 27th he outlined new plans for rockets that dwarf the Apollo programme’s Saturn V, and for spaceships with room for around 100 passengers that can be refuelled both in orbit and on Mars. Such infrastructure, he says, would eventually allow thousands of settlers to get there for $200,000 each—roughly the median cost of an American house. To deliver such marvels in a decade or so is an order tall enough to reach halfway to orbit itself (see article). But as a vision, its ambition enthralls. How odd, then, that Mr Musk’s motivation is born in part of a fear as misplaced as it is striking. He portrays a Mars colony as a hedge against Earth-bound extinction. Science-fiction fans have long been familiar with this sort of angst about existential risks—in the 1950s Arthur C. Clarke told them that, confined to Earth “humanity had too many eggs in one rather fragile basket.” Others agree. Stephen Hawking, a noted physicist, is one of those given to such fits of the collywobbles. If humans stick to a single planet, he warns, they will be sitting ducks for a supervirus, a malevolent artificial intelligence or a nuclear war that could finish off the whole lot of them at any time. Claptrap. It is true that, in the long run, Earth will become uninhabitable. But that long run is about a billion years. To concern oneself with such eventualities is to take an aversion to short-termism beyond the salutary. (For comparison, a billion years ago the most complex creature on the planet was a very simple seaweed.) Yes, a natural or maliciously designed pandemic might kill billions. So might a nuclear war; at a pinch climate change might wreak similar havoc. But extinction is more than just unprecedented mass mortality; it requires getting rid of everyone. Neither diseases nor wars do that. Otherworldly concerns An asteroid as big as the one that dispatched the dinosaurs might take out the whole species, but humans have had the foresight to catalogue the asteroids up to the task and none is coming close in the foreseeable future. So the chance of earthly extinction from any known cause in the next few centuries is remarkably low. As for the unknown—an evil AI, or predatory aliens with intellects as “vast and cool and unsympathetic” as those of Wells’s Martians, or the good old-fashioned wrath of God—why would they wipe humans from the face of one planet while leaving those on the rock next door in peace? If worrying about imminent extinction is unrealistic, trying to hide from it is ignoble. At the margins, it is better that the best and brightest share Earth’s risks than have a way to run away from them. Dream of Mars, by all means, but do so in a spirit of hope for new life, not fear of death. From the print edition: Leaders 644 words