George's Cosmic Treasure Hunt Read Online Free PDF Page A

into a nearby pile of books and finally—triumphantly—came up with a bright yellow volume that he waved in the air at George. On the front in big letters it said: The User’s Guide to the Universe .
    â€œDo you remember,” he asked George, “when I asked all my science friends at the party to write a page for me, answering some of the questions you posed? Well, I made their answers into a book—one for you and one for Annie. Here it is! When you read it, remember that I wanted you to understand something about being a scientist. I wanted to show you that me and my friends love to read one another’s work and talk about it. We exchange our theories and our ideas, and that’s one of the really important—and fun—parts of being a scientist: having colleagues who help, inspire, and challenge you. That’s what this book is all about. I thought maybe you’d like to look at the first few pages with me. I wrote them myself,” he added modestly.
    Eric started to read.

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    THE USER’S GUIDE TO THE UNIVERSE
    WHY DO WE GO INTO SPACE?
    Why do we go into space? Why go to all that effort and spend all that money just for a few lumps of Moon rock? Aren’t there better things we could be doing here on Earth?
    Well, it’s a bit like Europe before 1492. Back then, people thought it was a big waste of money to send Christopher Columbus off on a wild-goose chase. But then he discovered America, and that made a huge difference. Just think—if he hadn’t, we wouldn’t have the Big Mac. And lots of other things, of course.

    Spreading out into space will have an even greater effect. It will completely change the future of the human race; it could decide whether we have a future at all.
    It won’t solve any of our immediate problems on planet Earth, but it will help us look at them in a different way. The time has come when we need to look outward across the Universe rather than inward at ourselves on an increasingly overcrowded planet.
    Moving the human race out into space won’t happen quickly. By that I mean it could take hundreds, or even thousands, of years. We could have a base on the Moon within thirty years, reach Mars in fifty years, and explore the moons of the outer planets in two hundred years. By reach , I mean with manned—or should I say personed ?—flight. We have already driven rovers on Mars andlanded a probe on Titan, a moon of Saturn, but when we’re dealing with the future of the human race, we have to go there ourselves and not just send robots.
    But go where? Now that astronauts have lived for months on the International Space Station, we know that human beings can survive away from planet Earth. But we also know that living in zero gravity on the Space Station doesn’t just make it difficult to have a cup of tea! It’s not very good for people to live in zero gravity for a long time, so if we’re to have a base in space, we need it to be on a planet or moon.
    So which one shall we choose? The most obvious is the Moon. It is close and quite easy to get to. We’ve already landed on the Moon, and driven across it in a buggy. On the other hand, the Moon is small and without an atmosphere or a magnetic field to deflect the solar wind particles, like on Earth. There is no liquid water, but there may be ice in the craters at the north and south poles. A colony on the Moon could use this as a source of oxygen, with power provided by nuclear energy or solar panels. The Moon could be a base for travel to the rest of the Solar System.
    What about Mars? That’s our next obvious target. Mars is farther from the Sun than planet Earth is, so it gets less warmth from the sunlight, making temperatures much colder. Once, Mars had a magnetic field, but that decayed four billion years ago: It was stripped of most of its atmosphere,leaving it with only 1% of the pressure of the Earth’s atmosphere.
    In the past, the