2. 外语
  3. Scientists are searching for ways to destroy nuclear weapons in space—to make nuclear weapons powerless and no longer useful. Th

Scientists are searching for ways to destroy nuclear weapons in space—to make nuclear weapons powerless and no longer useful. Th

admin2013-03-27  59
问题     Scientists are searching for ways to destroy nuclear weapons in space—to make nuclear weapons powerless and no longer useful. This has become known as "Star Wars".(1)Supporters of the Star Wars defense system hope that this would not only protect a nation against an actual nuclear attack, but would be enough of a threat to keep a nuclear war from ever happening.
     (2)Opponents of Star Wars are worried that a system might introduce nuclear weapons into outer space and might not completely protect the nation against attack. Some missiles might "leak through" the Star Wars defenses. Or the computers that run the system might not work properly. Such a defense system, they say, might also be used to attack others. And it might not stop the buildup of ground-based nuclear weapons.
    Hopefully, a nuclear war will never begin. But, in such an event, could people really protect themselves? Supporters of Star Wars believe that laser weapons are the key to defense.(3)But can laser beams be developed in such a way to destroy attacking missiles in space? Lasers are not new. They have been around for over 25 years. They involve the following process;(4)Atoms of certain substances are stimulated, or excited, by a burst of energy from outside. The excited atoms then produce waves of light. These light waves travel up and down a laser rod and excite, or stimulate, other atoms. When a particular energy level is reached, the laser rod produces a strong, narrow beam of radiation. Most lasers give off visible light, but they can be built to produce heat radiation or even X-ray radiation.
    Because of the intensity and narrowness of their beams, lasers can be put to thousands of uses. Laser beams have been bounced off the moon. They can cut through diamond or steel. They are used by doctors for delicate surgery—such as repairing damaged eyes. And lasers are also used as weapons.(5)They can give artillery an accuracy as sharp as the point of a pin. They can also "blind" electronic systems in planes, tanks and ships. This means that those electronic systems can no longer effectively find and destroy their targets.
(4)
选项
答案某些物质的原子受到外界突然爆发的能量的刺激或激发，于是，这些受激原子产生光波。
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