你可能会这么想：既然电子邮件是“电子的”而且电子信息是以光速传播，那么电子邮件应该会在发出的几秒后到达目的地。
You would think that since E-mail is electronic and electronic information is suppose to move at the speed of light, your E-mail message would arrive seconds after you send it.
尽管先前的研究已经证实，光的“群速度”可以超越光速c，而“信号传播速度”——光携带的信息的传播速度——不能超越光速。
Although previous studies have found that the "group velocity" of light can travel faster than c, the "signal velocity" - the speed at which information travels - cannot.
尽管先前的研究已经证实，光的“群速度”可以超越光速c，而“信号传播速度”——光携带的信息的传播速度——不能超越光速。
Although previous studies have found that the "group velocity" of light can travel faster than c, the "signal velocity" -the speed at which information travels -cannot.
无线电波传播速度同光速一样，假设这种信使接收到我们于本世纪20年代的初次广播，则送往其母行星的信息现在仅走过一半路程。
Radio waves also travel at the speed of light, and assuming such an automatic messenger picked up our first broadcasts of the 1920's, the message to its home planet is barely halfway there.
无线电波传播速度同光速一样，假设这种信使接收到我们于本世纪20年代的初次广播，则送往其母行星的信息现在仅走过一半路程。
Radio waves also travel at the speed of light, and assuming such an automatic messenger picked up our first broadcasts of the 1920's, the message to its home planet is barely halfway there.
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