How Will the Human Body Evolve to Live On Other Planets?

Rubbish from the International Space Station about to be unloaded into our Solar System. (Photo via)

Have you ever talked about space exploration at the pub? Words like light-years, interstellar and landing module are banded around, and we all pretend to have a pretty firm grasp on what it would take to get the human race up to Mars, or beyond, before colonising it and turning it into a slightly floatier version of Earth.

Some might have even heard about Space-X, the privately funded space exploration company, or Mars One, a Dutch enterprise that hopes to send a bunch of people to the red planet for the rest of their lives. But what happens when they get there? How will the human body evolve to deal with living on a different rock to the one our species has spent hundreds of thousands of years adapting to?

One person asking these kinds of questions is Lord Martin Rees, Astronomer Royal and a professor of cosmology and astrophysics at the University of Cambridge. So I called him up for a chat.

Lord Martin Rees

VICE: Hi Martin. Can you explain to me what exactly your idea of a post-human – and a post-human future – is?
Lord Martin Rees: One thing we know is that Earth has a billion year future ahead of it where life could persist, which means there's plenty of time for evolution. Moreover, future evolution won’t happen on the slow timescale of Darwinian Natural Selection. Instead, it will happen via the application of technology. Within a couple of centuries we will be capable of altering our descendants via genetic engineering and "cyborg" techniques into almost a different species.

Do you think that would actually happen on a mass scale, though?
It may not happen here on Earth due to human choices and ethical preferences, but a century or two from now, small communities could possibly be living away from Earth in space. And surely we'd wish them the best of luck in adapting to alien environments through these kinds of drastic modification? It’s at this point that our species will diverge as we spread throughout the solar system.

That makes sense – the human body is presumably going to need a bit of work if its to cope in environments that we haven't naturally evolved to live in.
My prediction would be that, here on Earth, some cyborg-like modifications would take place through the process of melding ourselves with computers. The real scope of such changes, however, will occur via space pioneers. The environmental conditions that they will find themselves in will force them to adapt themselves. On Mars, for example, there is less gravity then here on Earth – and, on an asteroid, far less still. As a result, those living away from Earth will modify their physique, adapting towards what’s optimal for a very different environment.

What makes you think that will happen faster than previous natural evolution?
Darwinian Natural Selection has, in many ways, stopped, due to medical advancements and the fact that we can now keep people alive who otherwise would have died. Our knowledge of genetics and cyber techniques could bring about a much faster form of evolution. I’m confident that if we can survive the next century these kinds of changes will occur, but it’s harder to predict the timescale. But it’s not beyond the realms of possibility that such genetic and physical augmentation could occur over the next few hundred years.

What are your thoughts on nuclear power and its role in space exploration? 
Nuclear power will be very important in cutting the journey time between planets and moons. A nuclear rocket may not offer as much thrust as chemical rockets when it comes to launching a spacecraft, but what it does allow is sustained acceleration over a long time span. This helps build up speed and therefore cut journey time. Even with nuclear rockets, however, it will take far longer than the lifespan of a human to travel beyond our solar system to the nearest stars. So any such efforts will be a post-human enterprise. Travelling across the Milky Way for thousands of years may not seem daunting to creatures who are near immortal or can induce states of suspended animation. While the idea of warp drive seems impossible to us currently, we have to be open-minded to the idea that we may be unaware of certain scientific principles.

Do you think private space exploration enterprises – like Space-X, for example – are where those possibilities lie? 
If the Chinese committed themselves to leapfrogging NASA, they could obviously have an Apollo-like programme committed to landing on Mars. If that doesn’t happen, however, I genuinely believe that the first humans to land on Mars will be privately sponsored. The reason for this is that there is no real practical case for manned space flight – that’s because robots are much cheaper and are closing the gap with human capabilities.

Those humans who do land on Mars will therefore most likely be adventurers or thrill-seekers looking to push the limits of human endurance. Hope lies with companies such as Space-X because they look to build craft more cheaply, and also their passengers may accept higher risks than NASA could impose on civilian publicly-funded astronauts – risks that include radiation damage and the potential of sending someone to Mars with a one-way ticket.

An artist's impression of what the first human settlement on Mars might look like.

Given that, through the modifications you're talking about, post-humans could potentially become less organic, is it possible that extra-terrestrials could be completely synthetic?
Absolutely. The human brain carries with it many limits. A silicon-based intelligence could eventually far surpass the human brain in terms of mental capacity, and especially in speed. If extra-terrestrial intelligence is detected it’s quite likely that it will be non-organic, possibly created by a long extinct civilisation. Even though there are probably billions of Earth-like planets in our Galaxy, we don’t know how many are likely to have biospheres.

But if there are any planets similar to Earth which have evolved like the Earth, but for longer, then it’s perfectly possible that they will be populated by non-organic beings – computers that have the ability to simulate life itself. A much more far-out speculation, by the way, is that we could exist inside a simulation being carried out on a vast computer created by a more advanced civilization, akin to The Matrix. I think such an idea is pure science fiction. Having said that, it’s not against the fundamental laws of physics. Galactic scale super-civilisations could build computers on a planetary scale with stupendously massive processing power. So, while wildly futuristic, such civilisations are possible.

Finally, how tied is the survival of the human species to the stars?
The presence of a self-sustaining community of pioneers living away from Earth would be an assurance in the sense that it would mean that the post-human future wouldn’t be foreclosed even if everything was wiped out here on Earth. But even pessimists would rate the prospect of all humans being wiped out here on Earth as unlikely.

Having said that, the rapid advance of technology means that, 20 years from now, it’s likely that individuals or small groups will be able to create bioweapons in the same spirit that some people engage in cyber-terrorism. I worry about the problems of controlling this. If one person can cause a catastrophe then that’s one person too many. I genuinely believe that this prospect is going to present an intractable problem for all governments. We must strive to harness the benefits of ever more powerful technologies – bio, cyber and nano – while reducing the downside risks.

Thanks, Martin.

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