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Question: Who invented space travel?
That's a very interesting question. The answer depends on how you look at it!
In 1961, the Soviet Union first successfully sent an astronaut, Yuri Gagarin, into what we usually call "space". Under President Kennedy, the US competed with the Soviets and eventually took the lead. We were the first and only country to send someone to the moon. The first moon landing took place in 1969, the last in 1972. All other human voyages into space have been to the region between the earth and the moon.
But is this space travel? What about exploring the rest of the solar system? Or would true space travel mean going to distant stars, and their planets? When Neal Armstrong took the first step onto the moon's surface in 1969, he exclaimed, "a small step for man, a giant step for mankind." He meant that it was only the beginning, that soon we would have colonies on the moon and Mars, and would continue to explore ever outward from our home planet. Most Americans agreed with him. We thought exploring space would be similar to the European exploration of the "New World" after 1492. America has always been a frontier country, restlessly seeking new regions to explore, settle, and use, so Armstrong's picture of the future of space travel made sense to us.
But we were wrong. Although we have sent out unmanned satellites to ever greater distances, human beings still have not ventured beyond the moon. And while President Bush wants to send astronauts to Mars, we do not know if we can. For one thing, when humans are "weightless" (in space, far from the pull of gravity) they lose calcium from their bones. A trip to Mars and back might remove so much calcium that the astronaut would become completely disabled. Will we be able to overcome such challenges and travel to other planets?
The final step in inventing space travel would be to go beyond our solar system and explore the stars, and their solar systems. Perhaps out there are planets with life on them. According to Einstein, the greatest speed that any object can attain is the speed of light, 186,000 miles per second. Even if we could somehow invent a spaceship that traveled that fast, we would not want to because of some very unpleasant side effects. So, to travel even to the closest star would take many, many years (the closest star is very far away). Will we ever be able to do so? Not according to scientists' current understanding of physics and the nature of the universe. (But stay tuned, since our understanding of such matters may change).
In the years leading up to the moon landing, many of the astronauts who looked back at their home planet from space were struck by just how bound to Earth we are. They surmised that our planet is our "Spaceship Earth" - our only home, and in a sense our only true spaceship, in the vast inhospitable emptiness of space. If this perspective is correct, taking care of our environment here at home is crucial, since there is no chance of leaving and going somewhere else if we bollix things up.
So which view is correct? Will we eventually overcome the obstacles to space travel and colonization, and send our children, and theirs, out across first the solar system and then the galaxy; or must we remain always within the earth-moon system, entirely dependent for our sustenance on the resources that it provides? Kristin, you may learn the answer during your lifetime.
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