Aging in Space
Suppose a space traveler is moving at a velocity of 186,200 miles per second.
For every hour that passes for him, 30 hours pass on Earth. If he travels for a year in this fashion (having accelerated instantaneously) and then turns around and comes back at this speed (having turned around instantaneously), he will find that while he has seemed to himself to have traveled two years, the men on Earth would claim he had been absent for 30 years.
Suppose the space traveler had left at the age of 30, leaving behind a twin brother also aged 30. When he returned he would be 32, but his stay at home twin brother would be 60. That is why the “clock paradox”, is sometimes called the “twin paradox”.
Of course it takes quite a long while to accelerate to a high speed, and a long while to make a turn and head back again, so conditions aren’t quite as clear cut as just described.
1. The giant, spherical spaceship mentioned in the passage is ______.
[A]the outer space
[B]a man made spaceship
[C]the planet Earth
[D]the Star Wars mother ship
2. Some persons have traveled into outer space after conquering ______ within the past 25years.
[A]the universe
[B]Earth’s gravity
[C]the earth
[D]outer space
3. We have explored or sent robot spaceships to the following space except ______.
[A]the moon
[B]Venus
[C]Jupiter
[D]Mars
4. Why is the conquest of space more than a great adventure?
[A]Because it is full of challenges for human beings.
[B]Because it may be necessary for human beings to survive.
[C]Because it is the greatest adventure in human history.
[D]Because it is more exciting than any other adventures.
5. The moon and the asteroids are alike with respect to their ______.
[A]size and moving ways
[B]comfortable living conditions
[C]rich and valuable metals
[D]solar energy
6.Why can’t ultraviolet light scorch our skin on Earth as seriously as it does in space places?
[A]Because the Earth’s atmosphere can make ultraviolet light less harmful.
[B]Because ultraviolet can’t reach the Earth at all.
[C]Because the Earth is far away from those planets radiating ultraviolet light.
[D]Because other space places is near from those planets radiating ultraviolet light.
7. In spite of many risks, scientists will finally build ______ in space suitable for humans to live.
[A]an environment without ultraviolet light
[B]a lot of homes
[C]an Earth like environment
[D]an environment with atmosphere
8.The reason some metal alloys can’t be made on Earth is that the heavier metals _______ together with the lighter ones.
9. In space, there is no atmosphere to filter out the sun’s energy. There is plenty of solar energy to be turned into ______, for creating comfortable living conditions.
10. According to the author, ______will be caused to a man in gravity free space.