something strange happens to civilizations, strange in a bad way...,

aeon |  ‘I think there is a strong humanitarian argument for making life multi-planetary,’ he told me, ‘in order to safeguard the existence of humanity in the event that something catastrophic were to happen, in which case being poor or having a disease would be irrelevant, because humanity would be extinct. It would be like, “Good news, the problems of poverty and disease have been solved, but the bad news is there aren’t any humans left.”’

Musk has been pushing this line – Mars colonisation as extinction insurance – for more than a decade now, but not without pushback. ‘It’s funny,’ he told me. ‘Not everyone loves humanity. Either explicitly or implicitly, some people seem to think that humans are a blight on the Earth’s surface. They say things like, “Nature is so wonderful; things are always better in the countryside where there are no people around.” They imply that humanity and civilisation are less good than their absence. But I’m not in that school,’ he said. ‘I think we have a duty to maintain the light of consciousness, to make sure it continues into the future.’

Musk told me he often thinks about the mysterious absence of intelligent life in the observable Universe. Humans have yet to undertake an exhaustive, or even vigorous, search for extraterrestrial intelligence, of course. But we have gone a great deal further than a casual glance skyward. For more than 50 years, we have trained radio telescopes on nearby stars, hoping to detect an electromagnetic signal, a beacon beamed across the abyss. We have searched for sentry probes in our solar system, and we have examined local stars for evidence of alien engineering. Soon, we will begin looking for synthetic pollutants in the atmospheres of distant planets, and asteroid belts with missing metals, which might suggest mining activity.

The failure of these searches is mysterious, because human intelligence should not be special. Ever since the age of Copernicus, we have been told that we occupy a uniform Universe, a weblike structure stretching for tens of billions of light years, its every strand studded with starry discs, rich with planets and moons made from the same material as us. If nature obeys identical laws everywhere, then surely these vast reaches contain many cauldrons where energy is stirred into water and rock, until the three mix magically into life. And surely some of these places nurture those first fragile cells, until they evolve into intelligent creatures that band together to form civilisations, with the foresight and staying power to build starships.

‘At our current rate of technological growth, humanity is on a path to be godlike in its capabilities,’ Musk told me. ‘You could bicycle to Alpha Centauri in a few hundred thousand years, and that’s nothing on an evolutionary scale. If an advanced civilisation existed at any place in this galaxy, at any point in the past 13.8 billion years, why isn’t it everywhere? Even if it moved slowly, it would only need something like .01 per cent of the Universe’s lifespan to be everywhere. So why isn’t it?’

Musk has a more sinister theory. ‘The absence of any noticeable life may be an argument in favour of us being in a simulation,’ he told me. ‘Like when you’re playing an adventure game, and you can see the stars in the background, but you can’t ever get there. If it’s not a simulation, then maybe we’re in a lab and there’s some advanced alien civilisation that’s just watching how we develop, out of curiosity, like mould in a petri dish.’ Musk flipped through a few more possibilities, each packing a deeper existential chill than the last, until finally he came around to the import of it all. ‘If you look at our current technology level, something strange has to happen to civilisations, and I mean strange in a bad way,’ he said. ‘And it could be that there are a whole lot of dead, one-planet civilisations.’