The Future Of Space Exploration

Do you think the future of space exploration will be driven by the private sector?

Absolutely, new systems that are getting to orbit such as smaller space craft, space craft that act like airplanes that take off, land, refuel and off you go again. Probably even the return to the moon, I suspect, will be driven by the fact that people will pay a fortune. If someone offered you a chance to be the first man in 40 years to go to the moon; that's quite a holiday destination. And I am sure that will drive new technology and new ways of getting up there.

What are currently the most exiting areas of space research?

There are two. Let's start with the one relatively close to home, which is that we're beginning to see planets around other stars. The first was discovered in 1995. The latest count that we know of is about 300 planets around the stars, other than the sun. We're beginning to get a sense of whether our solar system is unusual or not. For the last 2000 years of astronomical history, we've only been able to look at our solar system. If you think about it, we've got the sun, and then there are rocky planets like Earth and Mars, and big gas things like Jupiter and Saturn. We thought that was normal. We came up very cleverly with a whole series of theories that explain why you have rocky planets close to the sun and big gaseous things further out. The only problem is that none of the other solar systems that we've seen look like this. You have large Jupiter-like planets closer to their stars than Mercury is to the sun. We have several large planets in the same solar system, and all of them close. We have planets on elliptical orbits, ones that are almost circular. We're beginning to see the whole range of planets, and we're nearly at the point where we can see Earth-like planets. At the moment, our techniques are not quite sensitive enough. In maybe the next year, or maybe the next 10 years, we'll be able to see if there are Earths out there and see how special this blue rock that we're standing on actually is. That's one thing. The other one that we've touched on is dark matter. Roughly ten years ago, for the first time in a long while, lots of different measurements about the universe came together to produce a theory of cosmology, a large-scale history of the universe that actually made sense. We know how old the universe is. In fact, we know how old the universe is more accurately than we know the age of the earth. We know that the universe began in a hot dense state that we call the Big Bang 13.7 billion years ago, plus or minus one hundred million years. We know that it expanded, we know what it's made of, although we don't know what dark matter is. We can predict what's going to happen in the future. It's great to have ticked off all of these boxes, but the best bit is that this picture makes no sense at all. We don't know what most of the matter is. There's also a mysterious force which is causing the universe to accelerate, and this goes by the name of dark energy. Trying to understand what that is and what on earth beyond Earth is going on is the challenge for the next 50 years.

Why is there so much discussion about Europa?

Europa's an amazing place. It's one of the large moons of Jupiter that Galileo discovered way back in the seventeenth century. And it's a strange world. It's got an icy surface, and we've known for a long while that that surface is predominantly winterized. And it has these grooves or cracks in it. And actually they look rather similar to the kind of thing you see in ice flows in Antarctica. If you look at a satellite photo of Antarctica, they look the same. So between that clue and essentially radar measurements at the center of the moon we've discovered that the middle of this thing is liquid. Now it's cold out there in the outer solar system, so it's not heated by the sun. It's actually the energy from Jupiter's gravity as the moon goes around Jupiter. Jupiter's so strong that it keeps the center of the moon liquid. Now why is this exciting? Well it might be a water ocean, warm, very similar to the kind of place that life first appeared on Earth. So, if we're looking for life in the solar system, maybe with Mars is the wrong place to look. That's where people have been focusing. Maybe what we need to do next is go to Europa; and both NASA and the European Space Agency a plot in missions where we go to Europa, land on the surface, and then just drill down through the ice. It might be a couple of meters thick, it might be tens of kilometers thick; but drill down, get into the ocean, and who knows, maybe the first photo they'll send back will be of something large with teeth.

Do you think mankind will ever colonise other planets?

I really hope so. I'd go to Mars for starters, and I've said this before, I'd go to Mars even if they weren't going to bring me back. The condition is that they'd have to keep me alive on the surface, but otherwise, how cool would it be to explore a new planet? Whether it would happen, well, it's difficult. Mars is a long way away. It takes probably, perhaps 18 months to get there. So if you're going to go, why not stay? It seems a waste to spend 18 months getting there, then turn around and come back. Whether it will happen in the near future, that's a more difficult question. I hope so, but a lot will depend on what happens in the next 20 years with the launch of private space companies. NASA have announced they're going back to the Moon and Mars, but all their budget, almost all their budget is going into manned programs. The Chinese are funding manned space programs, and how all these things interact, I'm not sure. Let's hope we're on Mars soon.

What area of astronomy do you specialize in?

I'm an astrochemist. Because we can get information about the universe not just from physics, but there is actually a surprisingly complicated chemistry up there as well. We have seen maybe one hundred and fifty different molecules up there. And they're everything from carbon dioxide, is quite common. And molecules that you might be interested in, for example, alcohol has been found in the star forming regions, and the Orion nebula I was talking about earlier, there's about a pint of alcohol. So, if only we could gather it, then that'd be useful. But there's a serious point here, because knowing that tells us about the conditions in those clouds. It gives us a huge amount of information. And one of the things we have found out is that chemistry goes a surprisingly long way. We form large organic molecules. Now, organic doesn't mean life bearing, it means large trains involving carbon, nitrogen, oxygen, and so on. And those are the building blocks of life. And if our theories are right, we've gotten as far as producing amino acids, the basic building blocks of proteins, in the star forming regions. If that's true, they're already there, when planets form. Which means life already has a head start, if they end up on a surface like the earth. We've got a long way towards producing life, even before the planet has formed. So I think, trying to understand that sequence of events is key. We need to do the whole thing. If you want to understand why there is life on earth, or even why there is intelligent life on earth, you need to understand how the universe began, you need to understand how galaxies formed, how stars formed within that, how planets form around those stars, how rocky planets form, and then what happened on the surface. My chemical models, and those of all the other astrochemists can cover almost that whole span, and give us a whole wealth of information about each stage in that process.

What's the future for the Sun?

Okay, well, the sun is a middle-aged star. It's been around in its current state for about four billion years, and we've got about four billion years left to go. Eventually, though, it's fueled by hydrogen, and eventually it will run out of hydrogen at its core. It will then swell up to the size of the earth's orbit -- what we call a red giant star -- and it will be burning helium in the center, to produce heavier elements. The Earth probably will just be saved. That's the good news. Because the sun loses mass, we're very slowly spiraling outwards. So where we're sitting now will probably be about the surface of the sun, and what's left of the Earth -- burnt to a crisp long ago -- will be a bit further out. So the planet will just survive. The red giant phase lasts maybe a billion years or so, if we're lucky, and then that's it for the sun. It can't produce any heavier elements in its core. It will run out of fuel. The outer layers will puff out in what's called a planetary nebula. That's absolutely beautiful. They last about ten thousand years. And all you're left with is essentially the core of the sun cooling down. That's what we see as a white dwarf, a dense ball of material which is just emitting radiation and gradually cooling down to the background temperature of space.

What's the future for the Universe?

Well let me tell you the bad news first, the Universe is past its peak; there are more stars dying than are being born so the galaxies are gradually fading. As they do, more black holes are being formed. Those that exist gradually consume more materials, and eventually, we'll end up with a universe of black holes and faint remnants of stars like the sun called "white walls," which are just cold balls of material that are gradually cooling down and that's it. That takes about a billion billion years and then that's it for a really really long time. Steven Hawking becomes important because his greatest contribution to science is the prediction of what's known as Hawking radiation; and this says that black holes gradually dissolve, very very slowly. I won't go into the details but black holes gradually give out light and that uses up energy. The energy has to come from somewhere so the black hole gradually shrinks. So for the next 10 to the 80 years (that's 1 followed by 80 zeroes), the black holes will gradually radiate and disappear into nothing. Now all this time, the universe is expanding; its being accelerated by a mysterious force called dark energy; so these black holes get further and further away from each other; and while they are giving out their light, if you were sitting on one, gradually you will see the universe appear to shrink, because although its expanding, everything else disappears over our horizon, so we're left with just one little black hole that we're sitting on and then gradually the black holes evaporate, and we're left with a sea of radiation that expands forever and ever. The end.