2018专八阅读理解练习题：太阳系内速度限制

2018专八阅读理解练习题：太阳系内速度限制

　　The marvelous telephone and television networkthat has now enmeshed the whole world, making allmen neighbours, cannot be extended into space. Itwill never be possible to converse with anyone onanother planet. Even with today's radio equipment, the messages will take minutes—sometimes hours—on their journey, because radio and light waves travel at the same limitedspeed of 186, 000 miles a second.

　　Twenty years from now you will be able to listen to a friend on Mars, but the words you hear willhave left his mouth at least three minutes earlier, and your reply will take a correspondingtime to reach him. In such circumstances, an exchange of verbal messages is possible—butnot a conversation.

　　To a culture which has come to take instantaneous communication for granted, as part of thevery structure of civilized life, this “time barrier” may have a profound psychologicalimpact. It will be a perpetual reminder of universal laws and limitations against which notall our technology can ever prevail. For it seems as certain as anything can be that no signal—still less any material object—can ever travel faster than light.

　　The velocity of light is the ultimate speed limit, being part of the very structure of space andtime. Within the narrow confines of the solar system, it will not handicap us too severely. At theworst, these will amount to twenty hours—the time it takes a radio signal to span the orbit ofPluto, the outer-most planet.

　　It is when we move out beyond the confines of the solar system that we come face to face withan altogether new order of cosmic reality. Even today, many otherwise educated men—likethose savages who can count to three but lump together all numbers beyond four—cannotgrasp the profound distinction between solar and stellar space. The first is the spaceenclosing our neighbouring worlds, the planets; the second is that which embraces those distantsuns, the stars, and it is literally millions of times greater. There is no such abrupt change ofscale in the terrestrial affairs.

　　Many conservative scientists, appalled by these cosmic gulfs, have denied that they can everbe crossed. Some people never learn; those who sixty years ago scoffed at the possibility offlight, and ten years ago laughed at the idea of travel to the planets, are now quite sure thatthe stars will always be beyond our reach. And again they are wrong, for they have failed tograsp the great lesson of our age—that if something is possible in theory, and no fundamentalscientific laws oppose its realization, then sooner or later it will be achieved.

　　One day we shall discover a really efficient means of propelling our space vehicles. Everytechnical device is always developed to its limit and the ultimate speed for spaceships is thevelocity of light. They will never reach that goal, but they will get very near it. And then thenearest star will be less than five years voyaging from the earth.[514 words]

　　11.For light to travel across the solar system, it will take_______.

　　[A] a year [B] nearly a day [C] two months [D] thirty minutes

　　12.The fact that it will never be possible to converse with someone on another planet showsthat________

　　[A] radio messages do not travel fast enough

　　[B] no object can ever travel faster than light

　　[C] western culture has a special idea of communication

　　[D] certain universal laws cannot be prevailed against

　　13.Confronted with the new order of cosmic reality, many educated men________.

　　[A] become ignorant savage again [B] find the “time barrier” unbearable

　　[C] will not combine solar and stellar space[D] cannot adapt to the abrupt change ofscale

　　14.Conservative scientists who deny that cosmic gulfs can ever be crossed will________

　　[A] laugh at the very idea of flight [B] learn a lesson as they did ten years ago

　　[C] find space travel beyond their reach[D] oppose the fundamental scientific laws

　　15.The author of the passage intends to show__________.

　　[A] the limitations of our technology [B] the vastness of the cosmic reality

　　[C] the prospect of planetary travel [D] the psychological impact of time and space

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