在线词典,在线翻译

光速与洲际高速

所属:听力板块 来源:普特英语听力 阅读:2231 次 评论:0 条 [我要评论]  [+我要收藏]

小编摘要:世界上跑得最快的是什么?答案是光速。它每秒能跑186,280英里。因为即使在太空中,光速也大致相同,所以光年也就用于描述不同星球之间的距离。

光速与洲际高速

 

 世界上跑得最快的是什么?答案是光速。它每秒能跑186,280英里。因为即使在太空中,光速也大致相同,所以光年也就用于描述不同星球之间的距离。记住了哦,光年是距离单位,不是时间单位。同时光这么快的速度又对我们有什么意义呢?一起听听吧。

If you’re driving on an interstate highway, the only thing keeping you from going faster than the speed limit is your sense of civic duty, or perhaps that police car up ahead.

There’s one speed limit, however, that most scientists agree nothing will ever break. That’s the speed of light:186,280 miles per second.


As it travels through deep space, light moves at exactly this speed, no more and no less.The speed of light is so reliable, we even use it to measure distances between the stars.

If it takes starlight fifty years to reach us, we say that this star is fifty light years away.

You might be surprised to learn, however, that light itself does not always travel at the speed of light.Our interstate highways generally have a higher speed limit, but once you enter a city or residential street, the speed limit lowers.

Likewise, light travels at its maximum speed through a vacuum the interstellar highway but it slows down when it enters air, water, or some other medium.

Through air, light moves a hint slower: forty miles per second less than its maximum speed.Through glass, light moves almost eighty thousand miles per second slower.

Light moves more than a hundred thousand miles per second slower through a diamond less than half its speed in a vacuum.

Light moves so quickly anyway, do we ever notice this change in speed? Actually, we do.When light slows down it also bends slightly.This is know as refraction.

Lenses use the lower speed limit of light in glass to bend and focus the light.If light always moved at it’s maximum speed, none of our telescopes, eyeglasses or even our eyes themselves would ever work.

标签:听力文摘
1
2011-11-01 21:51 编辑:pliny
分享到:
关注海词微博:
发表评论:
表达一些您的想法吧!已有0条评论>>
登录,再发表评论
文明上网,理性发言!
您可能还感兴趣的文章:
  • [听力板块]身体,你怎么啦?

    每次生病了,家里人最多说的一句话就是“不吃药怎么行?”。可是,有的时候吃药不一定就对身体有好处,反而有可能会帮助病原体“攻击”我们的身体。今天我们来了解了解一种新的理论“达尔文医学
  • [听力板块]利刃特别在何处

    大家都知道锋利的刀刃的切割性能胜过钝刀,但您知道确切原因吗?刀刃的作用就是把人们用在刀把上的力集中起来。
>>精华推荐阅读
热门评论文章