Behind the headlines about billionaire jaunts into space, there's a deeper motivation – the belief that spreading into the cosmos will save humanity's future. How did this idea emerge?

In the mid-1970s, the physicist Gerard O'Neill was reflecting on humanity's deep future in space – and concluded that his peers were thinking about it wrong. Lots of people talked about settling other planets, but he realised that there wasn't actually that much suitable real estate within the Solar System. Much of the planetary surface for building settlements exists within harsh, punishing atmospheres, and since rocky worlds and moons have gravity, going back and forth would be fuel-intensive.

Instead, O'Neill imagined enormous floating settlements, not too far away from Earth, shaped like cylinders. People would live on the inside, within green, forested towns, lakes and fields. It was a far-fetched idea, but thanks to the awe-inspiring visualisations that accompanied it – like the one below – O'Neill's dreams would influence a generation. And one of those people made international headlines this week.

In the 1980s, there was a student in O'Neill's seminars at Princeton University, who took careful note of his professor's ideas. He aspired to be a "space entrepreneur", and saw settlements beyond Earth as a way to ensure humanity's long-term future. "The Earth is finite," he had told his high-school newspaper, "and if the world economy and population is to keep expanding, space is the only way to go." He would go on to amass an enormous fortune, which one day he'd start spending to kickstart that ambition.

The student's name? Jeffrey Preston Bezos.

To understand why billionaires like Bezos want to go to space, you have to understand their influences. To casual observers, the efforts of Blue Origin and its competitors may seem to be no more than the vanity projects of a few extremely rich men, with extremely expensive rockets. And for many others, the timing of these jaunts could not be more tone-deaf, amid climate change, a pandemic, widening inequality and many other severe global problems.

But underpinning these efforts is a broader motivation that deserves deeper scrutiny: the idea of long-term salvation through space. Bezos is not the first person to propose that spreading out into the cosmos is the only way to guarantee humanity's future. People have dreamed of creating a civilisation beyond the atmosphere of Earth for well over a century, and future generations will likely continue to do so long after Bezos and his ilk have gone. So, what can these galactic goals tell us about this latest chapter?

The belief that galactic colonisation could help ensure humanity's future can be traced back a couple of hundred years. It's hard to imagine today, but people didn't always believe the Universe was unpopulated, and open to potential settlement.

Until the late 1800s and early 20th Century, scholars "felt the Universe was full of value and humanoids", says Thomas Moynihan, who studies intellectual history at the University of Oxford. As he wrote recently, if people imagined other worlds, they pictured other civilisations living there, rather than barren planets within a bleak, empty vacuum. "There was no motivation to imagine us going elsewhere and settling otherwise uninhabited spaces," he says. "There are stories of trips to the Moon and other planets, and even mention of conflicts, but these are just that: trips. And they are trips to go see the curious, but ultimately all-too-human occupants."

The idea that the cosmos is almost certainly predominantly empty – a vast region that we could expand into – is therefore a relatively recent realisation in human history, says Moynihan. What prompted scholars to think more seriously about settling the Solar System and beyond was also the dawning awareness that our species could one day go extinct, via the Sun's death or some other fate.

For a while, imagining the end of everything was coupled with a glum pessimism, but in the early 1900s, the discovery that the atom held huge amounts of power sparked a new wave of optimism that galactic colonisation could be the long-term solution, says Moynihan.

One of the most colourful proposals came from the Russian rocketeer Konstantin Tsiolkovsky, who imagined settling on asteroids with nuclear-powered spacecraft. "The best part of humanity, in all likelihood, will never die, but will migrate from sun to sun as they go out", Tsiolkovsky wrote in 1911.

This Russian "cosmism" of Tsiolkovsky and his peers had a religiosity to it, framing the settling of the Universe as a grand narrative of human destiny, calling for our species to spread life to the barren cosmos. But as Moynihan points out, this was definitely not a capitalist vision. In 1902, Tsiolkovsky's mentor, Nikolai Fedorov had worried that "'millionaires' might 'infect' other planets with their extractive exploitation", he says.

Over in the West, though, secular visions of galactic salvation began to emerge too. Another influential figure was the American engineer Robert Goddard, who created the first liquid-fuelled rocket. In 1918, he wrote a little-known short essay called the "Final Migration: A Note for Optimists" that he circulated among friends. "There he says if we can unlock the atom, we can send humans beyond the Solar System," says Moynihan. Goddard envisaged expeditions carrying all humanity's knowledge so that, in his words, a "new civilisation could begin where the old ended". And if that wasn't possible, he proposed the radical idea of launching "protoplasm" instead, which would seed new human beings on distant worlds eventually.

All this led to the idea that if humanity could settle the Milky Way, it might survive for tens of trillions of years, says Moynihan. And in many ways, these beliefs have underpinned visions of galactic settlement ever since – including those of Bezos, and another of the space billionaires, Elon Musk.

As a teenager, Bezos framed his ambitions as a path to infinite energy and resources that would be impossible if we stayed on Earth. And little has changed: he sees the idea of space settlements as a route to saving our species from its insatiable thirst for growth and resources. If it was up to him, humanity would move all polluting, heavy industry off-planet, and in the longer-term, spread out into O'Neill cylinders. He acknowledges that he won't create that future, but sees himself as a "road-builder", providing the infrastructure for future generations to do so.

The "go to space, save humanity" argument isn't as strong as the billionaires present it
Musk is more direct about extinction risk, arguing that if we become multi-planetary – settling on Mars, in particular – then a catastrophe on Earth needn't wipe out our entire species. The SpaceX billionaire is influenced by the idea of transcending the "Great Filter", the proposal that all civilisations in the cosmos face a cut-off point in their evolution that kills them off. Musk hopes that we could be the first in the galaxy to pass that filter point.

Moynihan, however, points out that the "go to space, save humanity" argument isn't as strong as the billionaires present it, especially at this particular moment in time. This century, we face myriad existential threats that are not localised and could easily spread, from bioengineered pandemics to misaligned artificial intelligence. It's possible such threats could reach beyond Earth. "Rushing to become multi-planetary might not provide a failsafe against every worst-case risk, says Moynihan. "In the immediate term, sparking a worldwide conversation on the issue of extreme risks may be more cost-effective than sprinting to Mars."

And as for climate change? While it is unlikely to be an existential risk, it promises to cause a huge amount of suffering to billions of people in the near-term – and there's not much that space tourism nor a galactic settlement project in the far future will do to help avoid that today.

Amid floods, wildfires and heatwaves, there have been plenty of critics of the billionaire era of space travel. Based on the severity of the problems we face, there are some today who might rather abandon visions of galactic settlement altogether – at least in the near-term.

That sentiment was captured in a recent essay by the science fiction writer Sim Kern, who pointed out that space may offer the alluring ideal of salvation and starting afresh, but in truth, "there's no leaving our messiness behind, no matter how many light-years away we travel".

And in any case, Kern writes, we have a pretty nice orbiting settlement already:

"It is enormous, big enough to bring all our friends and family along. It has excellent gravity and radiation shielding in the form of a breathable atmosphere. It comes with a nearly-unlimited renewable energy source – the Sun – which should last us another billion years before it gets too hot and burns us up.

"Our spaceship is peopled with more than eight million different alien life forms for us to study, whose behaviours and languages and intelligences we’re only beginning to understand. These other-species friends provide us with air, food, medicines, water filtration – some even sing for us, perfume our air, and make our ship breathtakingly beautiful."

If our descendants in the future were to agree, this is known as the "The Bullerby scenario", named after the idyllic rural life of Sweden in children’s books by Astrid Lindgren. It imagines that humanity eventually decides to ignore space, and instead focus on Earth, building a steady-state society with green energy, sustainable agriculture and so on. If intelligent extra-terrestrial civilisations have made this choice too, this could explain why we haven't seen any yet: perhaps they're living the life of Bullerby instead.

What about the really long-term though? If we're talking hundreds of thousands of years, then spreading across the Solar System and Milky Way can be taken more seriously as an argument for ensuring the future of humanity. Even those who disagree with starting the project now would be hard-pressed to justify delaying it until the moment before humanity collapses – that would be a disaster of unimaginable scale.

The average mammalian species has a 1-million-year lifespan, which suggests that at some point our time will come if we do nothing to prevent it. Catastrophes that could wipe us out are inevitable in deep time. But unlike other animals, we have advanced intelligence, so many researchers believe that taking the "astronomical" path beyond Earth promises a much longer future for our species. If we have settlements all over the galaxy, humanity becomes far more robust.

"I'm very fond of not having all the eggs in the same relatively fragile baskets," says Anders Sandberg, also at the University of Oxford. "Space colonies are way more fragile than planets, and vulnerable, but you can build more of them," he says. "Once you're actually able to build some big ones, you're going to be able to build a lot of small ones too. And at this point, that looks like you can reduce risks."

I'm very fond of not having all the eggs in the same relatively fragile baskets
Moynihan agrees. "It remains true that for humanity to fulfil its longest-term potential, it must eventually reach beyond," he writes. "Earth will ultimately become uninhabitable as our Sun ages. But the wider Universe will remain capable of supporting life – and the richness of consciousness – for aeons beyond this."

The trouble is, even in the deep future, there will always be reasons not to start the project. There will always be urgent problems we need to fix, back on Earth. "Becoming multi-planetary is a great vision and a good thing in the long run, but it might never really be a rational thing to do," says Sandberg. "I think there might even be a weird kind of selection for the slightly exuberant and the irrational." He cites the dictum that "all progress depends on the unreasonable man". "It might be that it's actually unreasonable what Bezos or Musk are doing, but it might still be a good thing." (In the long-run, at least.)

Whatever you think of the current generation of billionaires – their priorities, personalities, wealth, attitudes towards inequality or climate change, or treatment of their employees – there's no denying that they have made significant progress in space travel in a short space of time. Could it have been left to future generations instead of them? Maybe. But that doesn't make their contributions worthless.

Sandberg recalls a conversation with Musk, many years before SpaceX had sent rockets to space and back, when the entrepreneur visited him and colleagues at Oxford University's Future of Humanity Institute. "[He] was literally doing drawings on a napkin at the Grand Cafe here in Oxford to explain to me how he felt he could totally make something way cheaper than what Nasa was doing," recalls Sandberg. "I was nodding and saying 'I hope you're right'. Well, he proved himself."

However, Sandberg points out that if humanity does go on to build a galactic civilisation that saves its long-term future, it needn't be built according to the whims and desires of one or two billionaires in the early 21st Century. "If we don't want space to be set by a few particular people's visions, then the rest of us should also make our wishes known," he says.

Those who criticise the billionaire generation worry that their visions fail to take account of many present-day concerns, such as social justice and inequality. However, there might be opportunities to integrate some of these issues within space exploration plans. For example, the linguist Sheri Wells-Jensen has long been making the case for integrating astronauts with disabilities within space programmes. This year, the European Space Agency apparently took her advice, putting out a recruitment call for "parastronauts".

And while many might wish to focus their energies on climate change and other problems in the near-term, the future generations who are helped by their efforts may well decide to rejoin the space project in the deeper future. After all, it wasn't always the case that the priorities of space explorers and environmentalists were misaligned. The images of the Earth as a "pale blue dot" helped to show what was worth preserving about our planet, and Sandberg points out that without satellites we'd have a much weaker scientific understanding of climate change.

In the long-run, expanding into space could be a humanity-wide project, rather than one decided by a handful of people in Silicon Valley. A galactic civilisation may well lie in our future, eventually. Perhaps Bezos's dreams of an O'Neill cylinder will become reality. Perhaps it could help to save our species. But wherever we end up, that future will be shaped by citizens of the Milky Way with their own priorities and desires – and who are living long after the 21st Century's richest men have gone.

BBC

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