Space

Why Mars is first for human colonisation and then beyond

Brian Cox, professor of particle physics at Manchester University and TV presenter, talks about life on Mars, spotting alien lifeforms and how human kind can colonise space. Monday, 26 March

By National Geographic Team

Professor Brian Cox is guest editor of the March 2018 issue, which also includes personal reflections of astronauts and looks back at the success of the Cassini project. Here he reflects on life on Mars, colonising space and whether we have missed spotting alien life forms.

Is SpaceX founder Elon Musk’s proposal to launch humans to Mars by 2024 realistic?

I’ve talked to Musk about this and I think he’s being over-ambitious. Mars’ and Earth’s orbits will bring the two planets closer in the 2030s, so that would be a good launch window. My guess is it’s more likely to be the early 2030s. I’ve been to his factory and, admittedly, he does have the rockets. He has got plans to send people around the Moon in 2018. But he has not even launched an astronaut to the International Space Station yet.

When can we expect to see a Mars colony and humans spreading throughout the solar system?

Regarding a Mars colony, you have to look at it the other way around. You almost establish the colony first. You send the base there; you land it, make sure it’s working. Then you send the astronauts.

Once you've gone to Mars, and you have the rockets, it’s then all about building bigger habitation modules on the spacecraft so you can travel further. I would imagine that, by 2050, humans will have a colony on Mars and the Moon, and be operating on the asteroids.

I think Jupiter’s a bit tricky because the radiation is horrendous. But the moons of the big gas giants – I can imagine people visiting them. Saturn’s moon Enceladus might have life in its subsurface ocean. If it did have life we wouldn’t land on it; we’d have to be very careful with it. But many people talk about visiting Titan, Saturn’s largest moon. As long as we are at Mars by the early 2030s, I could imagine we’d be on places such as Titan at the end of the century. (Related: The Value Of Perspective.)

Are we destined to leave our solar system eventually?

The next ten or 20 years are critical for us. If we make that step to Mars, it would mean we have the rocket capability and technology to start exploring the solar system. Then, I think, a space-faring civilisation is inevitable. Therefore, we might eventually become an inter-stellar civilisation. But that's much more difficult. I think that would require a time scale of several hundred years.

There are obviously fundamental limits to the speed you can travel. It is an order of magnitude much more difficult to travel over four light years to the nearest star than it is to hop around to Jupiter and Saturn. But technology will advance very quickly over the next few hundred years. Remember, we’ve only had a technological civilisation for several hundred years.

If we do explore beyond the solar system, it might not be us; it might be our robot descendants. We tend to be quite bio-centric about these things. If I had to guess, I’d say that after the next century or so we’ll have machines that are explorers on our behalf. Or we may send frozen human embryos. I don't see why you’d need a human crew. We’re not well adapted to space travel. Not yet.

How important are TV scientists like you in engendering public support for expensive space missions?

I think, from now on, space exploration is going to be a public-private partnership, or even a purely private one. The industrialisation of near space and outwards towards the asteroids is inevitable. There’s a business case now that will attract private investments in that. It is ridiculous to farm or stress this planet in our quest for resources when there are huge amounts of it above our heads. Not far away, the amount of resources in the asteroids dwarfs anything we have on Earth.

We are no longer in a position where we have to continually convince tax-payers that technological progress is a good idea. It will happen anyway. The likes of Blue Origin and SpaceX have done what no government has been able to do: produce reusable rockets. We need to find a way of expanding continually our civilisation whilst at the same time not destroying the planet. As scientists in the media, we can talk about our short-term, medium-term and long-term future. Politicians are certainly not the best people to ask or answer those questions.

So far we have never discovered any evidence for extra-terrestrial civilisations. Is it possible we have failed to spot the evidence?

The original way to search was to listen out for radio transmissions. We’ve done a lot of that and we haven’t heard anything. You might explain this by suggesting that civilisations became radio silent long before we started listening. After all, we are to an extent almost radio silent ourselves: we tend to broadcast less now because we have optical fibres all over the place. We don’t have high-power TV transmissions any more; instead we have low-power transmissions which are very focused.

Perhaps we should have spotted alien spacecraft by now. Way back in the 1950s the mathematician John von Neumann suggested that a civilisation might get to the point where it builds self-replicating machines that can travel through space, find raw materials, and create copies of themselves. These machines would continue travelling and self-replicating.

Mathematically you can show that they might spread throughout a typical galaxy within a few hundred thousand years. If you think, there have been billions of years of time in our galaxy so that you would expect to see evidence of at least one civilisation using self-replicating machines to become an inter-planetary species. It is therefore very difficult to understand why we haven’t seen anything.

Granted, you might say that those self-replicating machines are more like nanobots – tiny little machines that we can’t see – than spacecraft. You could argue that they are present in our solar system but they are so incredibly tiny and so energy-efficient that we can’t see their signatures.

As a TV scientist, you are famous for explaining very complex ideas very succinctly to a lay audience. Are there any ideas of physics so complex that you struggle to understand them?

Yes. For example, our search for a quantum theory of gravity is extremely complicated. That's the theory that replaces Einstein’s general theory of relativity. It’s an extremely difficult area of mathematics and physics to understand, unless you’re an absolute specialist and professional in this field. I don’t know anyone who’s not in fields such as string theory who understands it. Modern theoretical physics is very compartmentalised. Very few people understand it all.

Related: Where Next For Voyager?