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BBC Space New Worlds

where the sun is brilliant, powerful, giver of life We'll need to seek out new homes in amazing new places. And change other worlds to recreate the Earth we left behind. In the far future, our sun will become bad. Our sun will die and we'll go with it. It's time to think about the future. For five billion years, the sun has nourished the Earth. It is the sun that provides energy for plants to grow. It is the sun that makes life on Earth possible. But that will change. Slowly, unstoppably, our sun is getting hotter and hotter. Once it gave life to us all. But what it gave it can also take away. If human beings are to have a long-term future, we must leave our planet behind and search for new places to live. One day, our homes will be out there somewhere in space. In the distant future, this could be our home. Out here in space, we'll have to seek refuge on new worlds where we could settle and live. And the reason is we have to escape from our sun. Some new worlds may be difficult to adapt to. Others may be very like our own. But what is it that makes our planet so special? And why is it so dependent on the sun? Here is the sun as it is today, in the centre of our solar system. The Earth goes round it about there. And there are the other planets. The reason our planet is the one with life on it is that it's the right distance from the sun. Closer in and we'd boil, further out and we'd freeze. We live in a kind of safe zone that's perfect for life. Trouble is that zone is moving. The sun is getting hotter and the region where life can exist is shifting further out. Ultimately, the safe zone will leave Earth behind. When it does, we'll be in serious trouble. Our planet will die. This is how it will happen. As the sun burns up its nuclear energy it'll become ever hotter. By the time it's 5% hotter, plant life everywhere will be dying. Will begin to die. will evaporate, creating huge cloud banks, trapping more and more heat. And there's nothing we can do about it. What will happen to us then? Astronautical engineer Robert Zubrin believes he has the answer. He wants to find us a new place to live. The only real choice that we have is to grow, expand, become a space-faring civilization, or become extinct. Not only would WE become extinct, but unless we bring Earth life out with us into the universe, all life on Earth will become extinct. Robert Zubrin's goal is to make us a home on Mars. Today, Mars is cold and lifeless. Temperatures regularly drop to 100 below freezing. Its atmosphere is 200 times thinner than ours. A person standing unprotected on the surface would die in seconds. Yet some scientists believe we could learn to call this home. Mars is the only other planet in our solar system that has all the resources needed to support life. It has water, albeit frozen as ice and permafrost. It's got carbon dioxide and nitrogen in the atmosphere. If humans go to Mars and develop the craft of using these resources, then we can make Mars a place where we can sustain ourselves. A world for our posterity. No species can expect to last long if it stays in one place. In a sense, humans aren't native to the Earth. We're not native to America or Europe. We're native to Kenya - long arms, no fur. But humans were able to leave there and colonize the Earth by becoming creative. That's how we coped with Ice Age Europe and it's how we'll cope with Mars. Living in a space pod did prove difficult, but they coped. Zubrin is optimistic. We're ready to take this on. When we think about going into space, we focus on humans. In fact, it's easier for plants and micro organisms to go to Mars firs they’ll be the first Martians. The machines' job is to suck up a mixture of dust and atmosphere and process it into new chemicals. It belches out these greenhouse gases to warm the planet and dark soot to soak up heat from the sun. If we send enough machines, over time, Mars will warm enough to allow these algae to survive. The algae will begin to give Mars an oxygen atmosphere.


 
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As the sun becomes hotter, new worlds will form into life
As the sun becomes hotter, new worlds will form into life
  Arizona Desert completely sealed off from the planet
Arizona Desert completely sealed off from the planet
  Researchers have already been preparing for life on Mars
Researchers have already been preparing for life on Mars
  There will come a time when we must leave our Earth behind and our home will be in space
There will come a time when we must leave our Earth behind and our home will be in space
 
But for speed, we'd need more efficient oxygen makers. And the best that we know are plants and trees. The real goal is to get trees growing there. Those trees will be the ones that make a habitable world. Then things will really start happening as the oxygen level rose, insects then larger animals could survive. We could change Mars. With Mars dead, where next? Once again, human beings will be looking for a new home. And, once again, we'll have to move further from our brightening sun. But the planets further out are impossibly hostile worlds. Gas giants like Jupiter and Saturn are not places we could ever hope to transform. If we're going to survive on these alien worlds, it won't be the planets we'll have to change we may have to change ourselves. David Brin is a science fiction writer. He imagines future worlds for a living. It's a big universe and the Earth is a very specialized environment. We won't find many Earths out there. If we want to spread out, then we're going to have to adapt to the universe. It's not easy for humans to get accustomed to that idea because we're used to making the universe adapt to us. Five, four, three, two, one! This is Europa, one of Jupiter's huge moons. We know it today as a frozen planet - airless, with a crust of iron-hard ice. But in the future, it will be something else entirely. The ice will have melted. Europa will become an ocean world. After Mars, perhaps we'll come here and make this our new home. We could live in cities at the bottom of an alien sea. But David Brin thinks that, in the end, a life behind glass may not be the solution. Now we're thinking of going to other planets. At first, we'll arrive in spacesuits, live in domes, and bring environments with us. But we'll want to get out of those domes, so we'll have to change ourselves to fit into new environments. Our ancestors evolved for life on Earth. But Brin thinks our descendants may redesign themselves for a future on other worlds. Human beings have been wonderfully inventive in the last 20 million years. Seven billion years from now, the Earth will be gone.     For us today, one question remains. Is the future of our planet also OUR future? Can we really survive the death of Planet Earth? Look at how far we have come. Compared to the world of 100 years ago, we're living in a science fiction universe with skyscrapers 100 story tall! Who can believe, seeing that, that looking forward 100 years, there will not be a new civilization on Mars? And look back 1,000 years - the world lit only by fire. Who can say that 1,000 years from now, there will not be hundreds of new branches of human civilization filling worlds, orbiting hundreds of stars and listening to the galaxy? Some people think that we are living at the end of history, but I think we're living at the beginning of time. We're present at the creation. It's a glorious time to live. We might be the only life form in the universe. If that's true, that really deepens the importance of spreading life beyond the Earth. If we're the only spark of life, we certainly don't want that spark to go out. Our scientists today are already imagining strange, far-off tomorrows for our kind. And, if we do survive, perhaps we will be there to witness the moment when our sun's transformations finally end. It was first the giver of life, then the destroyer of worlds and now, it, too, is doomed. This is the sun at the end of its life. Layer after layer, it is blowing itself apart. Huge clouds of star stuff drift into space. It's a slow process that takes millions of years. What follows is inevitable - the death of our sun. It casts off one final layer, and its spark is extinguished forever. So, the sun will one day go out. Will it be significant to our descendants in billions of years? I don't think so. They will have observed similar phenomena on innumerable other stars before then. But, if they did think about it, they'd note with gratitude that their ancestors did not stay on that one little world and await their doom, but spread into the universe and made their life possible. No one can know our future, but our sun's future is certain.