Mars is your passion…what one question would you like answered?
I've spent 40 years pursuing the mystery of what Mars's surface is like, and most importantly, what is the history that represented by it. And I've been defeated again and again by Mars, even though there are much more powerful tools, much better spacecraft, more data, better instruments. They provide new insights, but they end up breaking the unifying idea we had before, which is called a paradigm -- like the continental drift was when it was first proposed about 1960 for the earth and revolutionized the fields of geology and geophysics. That continues to revolutionize and it continues to provide a framework to put everything together. We lack that from Mars, and I think, to me, that's the most exciting thing. What is that paradox?
How should we define life?
Best example I know was for the Viking mission to Mars, which arrived there in 1976, whose main purpose was to search for microbial life in the soil of Mars not knowing anything about it, whether it's there, what it would be like. And so they had to decide, well, how do we search for it? And the idea that won favor among the biologists then -- I think it's still the most powerful one -- is that a characteristic of life is that it metabolizes. It interacts with its environment. It grows. So you have to see growth. So I think that's one definition, sort of a laboratory definition, that still makes a lot of sense to me. If we can't culture it, if we can't grow it, it's going to be very hard to prove it's alive, even if it might be in some sense.
Will we ever discover intelligent life?
I think we're going to discover intelligent life, but we will get it remotely through radio signals or laser beams or others. I find it very difficult, for the reasons of how difficult it is to travel between stars, to imagine "Star Trek"-type aliens coming to different stars. I think there are aliens. I don't think there's any question in my mind. I'd be astounded if there are not. But the idea of them shooting around the galaxy or the universe or whatever in ships, I think, is unlikely. So unless there's some new physics, and there might be, I don't see that happening. They will, however, be able to communicate with us and we with them simply with what we already have, with radio telescopes and radar, as well as more powerful kinds of remote communication.
Do you believe in life elsewhere?
Absolutely, I hope we'll find life elsewhere. I hope we'll get dethroned. And I fear for those guys who will see their cozy world disappear. I think that's one of the reasons why I like being in this field because this is the ultimate argument against parochial ideas like religion.
How will it effect us when we find it?
Oh, I think it'll effect us in the most profound way because a large part of our energy right now, and perhaps historically, goes into differentiating ourselves. You open the newspaper, and you look at how much energy is going into various conflicts and military expenditures. And the energy there and the money that society puts into either immediate or perceived conflicts really is not trivial. Part of that comes from a very parochial view that if I dominate locally, then I'm the big boss. But you take this assumption away, and suddenly, the earth is very different. I think this will be the ultimate completion of what people are calling the Copernican revolution. It'll dethrone our sense of importance. And whether you like it or not, I think that is what's going to happen when we find evidence of other life elsewhere.
Why haven't we been visited before?
The simplest answer is that it's very difficult for people to travel, so that's why we haven't seen anyone and they haven't seen us. Even if they're a billion years older than us, the speed of light is the law for everyone. The other reason we haven't been visited is that maybe civilizations don't have long lives, which basically means they'll never get to the point where they can muster whatever sophisticated technology they need to make this happen. Our own history, too, is so young. Perhaps, that is the other answer.
Has the Hubble telescope been useful in finding planets?
In order to search for extra-solar planets, the Hubble Space Telescope has reinstalled this instrument called NICMOS, Near Infrared Camera Multiple Object Spectrograph. And basically, while much of the Hubble's instruments have the same range as our own eye -- that is, they can see what we call visible rays -- the NICMOS can actually see the heat rays from the infrared rays, which is an excellent vehicle for studying how stars are born and for looking for very young planets and so on.