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.
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