dijous, 5 d’agost del 2010

Kingdom of life is the universe

Europa is one of the moons of Jupiter, where we see a very level ice surface which looks as if it's floating on top of an ocean. So we believe that on Europa there is in fact a deep ocean. And that makes it extraordinarily interesting as a place to explore. Ocean -- probably the most likely place for life to originate, just as it originated on the earth. So we would love to explore Europa, to go down through the ice, find out who is swimming around in the ocean whether there are fish or seaweed or sea monsters.

Imagine that life originated on Europa, and it was sitting in the ocean for billions of years. It's quite likely that it would move out of the ocean onto the surface, just as it did on the earth. Staying in the ocean and evolving in the ocean for 2 billion years, finally came out onto the land. And then of course it had great, much greater freedom, and a much greater variety of creatures developed on the land than had ever been possible in the ocean. And the step from the ocean to the land was not easy, but it happened.

Now, if life had originated on Europa in the ocean, it could also have moved out onto the surface. There wouldn't have been any air there, it's a vacuum. It is out in the cold, but it still could have come. You can imagine that the plants growing up like kelp through cracks in the ice, growing on the surface. What would they need in order to grow on the surface?
They'd need, first of all, to have a thick skin to protect themselves from losing water through the skin. So they would have to have something like a reptilian skin. But better, what is more important is, that they would have to concentrate sunlight.

The sunlight in Jupiter, on the satellites of Jupiter, is 25 times fainter than it is here, since Jupiter is five times as far from the sun. So they would have to have these creatures, which I call sunflowers, which I imagine living on the surface of Europa, would have to have either lenses or mirrors to concentrate sunlight, so they could keep themselves warm on the surface. Otherwise they would be at a temperature of minus 150, which is certainly not favorable for developing life, at least of the kind we know. But if they just simply could grow like leaves, little lenses and mirrors, to concentrate sunlight, then they could keep warm on the surface, they could enjoy all the benefits of the sunlight and have roots going down into the ocean, life then could flourish much more. So, why not look -- of course it's not very likely that there's life on the surface of Europa. None of these things is likely, but my philosophy is look for what's detectable, not for what's probable. There's a long history in astronomy of unlikely things turning out to be there.

If these creatures who are living on cold surfaces, either on Europa, or further out, anywhere where you can live on a cold surface, those creatures must be provided with reflectors. In order to concentrate sunlight, they have to have lenses and mirrors in order to keep themselves warm. And then when you shine sunlight at them, the sunlight will be reflected back just as it is in the eyes of an animal. So these creatures will be bright against the cold surroundings. And the further out you go in this, away from the Sun,more powerful this reflection will be. So actually, this method of hunting for life gets stronger and stronger as you go further away, because the optical reflectors have to be more powerful so the reflected light shines out even more in contrast against the dark background. So as you go further away from the Sun, this becomes more and more powerful. So in fact, you can look for these creatures with telescopes from the Earth.

Why aren't we doing it? Simply because nobody thought of it yet. But I hope that we shall look, and with any, we probably won't find anything, none of these speculations may have any basis in fact but still, it's a good chance. And of course if it happens it will transform our view of life altogether. Because it means that the way life can live out there, it has enormous advantages as compared with living on a planet.
It's extremely hard to move from one planet to another. We're having great difficulties at the moment and any creatures that live on a planet are pretty well stuck.

I call these creatures sunflowers. They look like, maybe like sunflowers. They have to be all the time pointing toward the sun, and they will be able to spread out in space, because gravity on these objects is weak. So they can collect sunlight from a big area. So they will, in fact, be quite easy for us to detect. So, I hope in the next 10 years, we'll find these creatures, and then of course our whole view of life in the universe will change.

If we don't find them, then we can create them ourselves. That's another wonderful opportunity that's opening. We can, as soon as we have a little bit more understanding of genetic engineering, one of the things you can do with your take it home, do-it-yourself, genetic engineering kit is to design a creature that can live on a cold satellite, a place like Europa, so we could colonize Europa with our own creatures. That would be a fun thing to do.

In the long run, of course, it would also make it possible for us to move out there. What's going to happen in the end, it's not going to be just humans colonizing space, it's going to be life moving out from the Earth, moving it into its kingdom. And the kingdom of life, of course, is going to be the universe.

Freeman Dyson, let's look for life in the outer solar system.