How humans could populate the universe in the next billion years

I’m old enough to have seen the grainy television footage of the first Apollo 11 moon landings in 1969. I can never look at the moon without remembering Neil Armstrong’s “One Small Step for a Man”; a giant leap for humanity. It seems even more heroic in retrospect, considering how dependent they were on primitive computing and untested equipment.

Once the race for the Moon was won, there was no motivation to continue the space race and the gargantuan costs involved. No human since 1972 has traveled more than a few hundred miles from Earth. Hundreds have ventured into space, but they have only circled the Earth in low orbit. In the mid-1960s, NASA absorbed 4% of the US federal budget; today it is 0.6%. If this momentum had been maintained, there would surely be footprints on Mars by now.

Nevertheless, space technology has experienced a boom over the past four decades. We regularly depend on thousands of satellites in orbit for communication, navigation, environmental monitoring, weather monitoring and forecasting. Space telescopes orbiting high above Earth’s atmosphere have returned images of the outermost cosmos. They probed the sky in infrared, UV, X-ray and gamma-ray bands that do not penetrate the atmosphere and therefore cannot be observed from the ground. They revealed evidence of black holes and probed the “afterglow of creation” – space-pervading microwaves, the properties of which hold clues to the very beginning, when the entire observable cosmos was reduced to microscopic size.

Of more immediate public interest are the discoveries of spacecraft that have traveled to every planet in the solar system. NASA’s New Horizons has sent back amazing images of Pluto, 12,000 times farther than the Moon. Rosetta of the European Space Agency has landed a robot on a comet. It took five years to design and build these spacecraft, and then almost ten years to reach their distant targets. The Cassini probe spent 13 years studying Saturn and its moons and was even more venerable: more than 20 years passed between its launch and its final plunge into Saturn in late 2017. These missions used technology from the 1990s; it’s not too hard to imagine how much more sophisticated today’s follow-ups could be – just think how dramatically smartphones have evolved over those decades.

During this century, the entire solar system – planets, moons and asteroids – will be explored and mapped by fleets of tiny automated probes, interacting with each other like a flock of birds. Manufacturers of giant robots will be able to build solar energy collectors and other giant lightweight structures in space. Just this week we saw the first images from the James Webb Telescope, which was launched in December – a big step up from the Hubble Telescope to deepen our view of the cosmos. It can probe 98% of cosmic history, the “genesis” of galaxies, and may find evidence of life on planets orbiting nearby stars. The telescope’s successors, with oversized mirrors assembled in zero gravity, will further expand our view of exoplanets, stars, galaxies and the wider universe. Future (and even larger) generations of instruments will be assembled by robots, which can also be used for space mining.

If there was a revival of the “Apollo spirit” and a renewed urge to build on its legacy, a permanent moon base would be a credible next step. It could be built entirely by robots, bringing supplies from Earth and mining from the Moon. A particularly suitable site for human habitation is the Shackleton crater at the lunar south pole, 21 km in diameter and with a rim 4 km high. Due to the location of the crater, its rim is always exposed to the sun and thus escapes the extreme monthly temperature contrasts experienced on the rest of the Moon’s surface. Additionally, there can be a lot of ice in the perpetually dark interior of the crater – crucial for maintaining a “settlement”.

Hopefully people who are alive today will walk on the Moon, and even on Mars. The future of manned spaceflight does not belong to governments, but to privately funded adventurers who will be willing to participate in a discounted program far riskier than Western nations. SpaceX, led by Elon Musk, or rival effort Blue Origin, funded by Jeff Bezos, will soon offer orbital flights to paying customers.

These companies – bringing a Silicon Valley culture to a field long dominated by NASA and a few aerospace conglomerates – have shown that it is possible to salvage and reuse the launch rocket’s first stage, presaging real cost savings. They innovated and improved rockets much faster than NASA or ESA. The future role of national agencies will be more like that of an airport than an airline.

More importantly, private companies can be less skittish than NASA and find volunteers willing to tolerate greater dangers that a Western government might impose on publicly funded civilian astronauts. So it’s these discount companies – with private sponsorship – that should be at the forefront of human space travel.

Later in the century, brave thrill-seekers – in the mold of (say) Sir Ranulph Fiennes, or early polar explorers – might well establish “bases” independent of Earth. Elon Musk himself (now 51) says he wants to “die on Mars but not on impact”.

But what is the longer-term scenario? Musk and my late colleague Stephen Hawking predicted that the first “settlers” on Mars would be followed by millions of others seeking to escape Earth’s troubles. But this is a dangerous illusion. Dealing with climate change is child’s play compared to terraforming Mars. Nowhere in our solar system offers such a clement environment as Antarctica, the summit of Everest or the bottom of the oceans.

Because humans will be ill-adapted to Martian conditions, they will have a more compelling incentive than those of us on Earth to rethink – and it may not remain science fiction. Indeed, it is surely on the cards that human beings – their mentality and their physique – can become malleable through the deployment of genetic modification.

For this, two advances are necessary: ​​first, an in-depth analysis of the human genome to determine which combination of genes optimizes the specific desired qualities; and second, the ability to synthesize a genome with these properties.

Optimists suspect that by the end of the century, “designer babies” will become conceivable (in both senses of that word). It is hoped that these techniques will be limited, because they are risky: the genome is so complicated that attempts to modify it can have unforeseen disadvantages that outweigh the advantages.

Another futuristic concept, more familiar from science fiction, is that our descendants could become ‘cyborgs’, their mental abilities being enhanced by linking the brain (or ‘plugging’ it in) to electronic attachments. It is the space adventurers, not those of us who are comfortably adapted to life on Earth, who will lead the post-human era – evolving within centuries into a new species. This evolution, best described as “age-old intelligent design,” could unfold on the time scale of technological progress, potentially thousands of times faster than Darwinian selection.

Moreover, there may be limits to the capacity of organic brains; perhaps humans are already close to that limit. If our descendants pass from flesh and blood to entirely inorganic intelligences, they will not need an atmosphere. And they may prefer weightlessness, especially for building massive artifacts. So it’s in deep space – not on Earth, not even on Mars – that non-biological “brains” can develop powers that humans can’t even imagine.

Billions of years await us. The Sun was formed 4.5 billion years ago: it took most of this immense time for life to evolve from its still mysterious beginnings into the immensely complex biosphere of which we are a part. Humans are not the highest point – the top of the tree. We may actually be closer to the beginning than the end of a cosmic process.

The Sun is still less than halfway through its life: it will survive another six billion years before its fuel runs out. And the expanding universe will continue much longer – perhaps forever. Thus, even if intelligent life had originated only on Earth, it would not necessarily remain a trivial feature of the cosmos: it could initiate a diaspora through which ever more complex intelligence would spread throughout the galaxy. Interstellar travel would have no terror for quasi-immortal electronic entities. There is plenty of time ahead of us.

Even though we are not the terminal branch of an evolutionary tree, humans could claim true cosmic significance for initiating the transition to electronic entities, extending their influence far beyond Earth.

This raises another question: will our distant offspring be the first intelligence to spread across the galaxy? Or will they encounter “aliens” already there, who originated from a planet around an older star where evolution was way ahead of us?

Perhaps the galaxy is already teeming with advanced life, and our descendants will “plug in” to a galactic community as “junior members”. On the other hand, Earth’s complex biosphere may be unique and searches for extraterrestrials may fail. Our little planet – that pale blue dot floating in space – could be the most important place in the entire cosmos.

Either way, our cosmic habitat seems “tuned” to be an abode for life. Even if we are alone in the universe, we may be far from the final destination of this “drive” towards complexity and consciousness.

“They don’t talk to me like Boris did.”

About Lucille Thompson

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