時(shí)差N小時(shí):時(shí)間之謎 時(shí)間的測(cè)量

If you can read a clock, you can know the time ofday. But no one knows what time itself is. We cannotsee it. We cannot touch it. We cannot hear it. Weknow it only by the way we mark its passing. For allour success in measuring the smallest parts of time,time remains one of the great mysteries of theuniverse.如果你會(huì)看鐘，你就能知道時(shí)間。但沒(méi)人了解時(shí)間本身。它看不見(jiàn)，摸不著，聽(tīng)不到。我們只能通過(guò)標(biāo)記它的流逝來(lái)認(rèn)識(shí)它。我們?cè)跍y(cè)量極短時(shí)間的成就有限，時(shí)間仍舊是宇宙最大的謎之一。

In the real world—the world with time—changes never stop. Some changes happen only once ina while, like an eclipse of the moon. Others happen repeatedly, like the rising and setting ofthe sun. Humans always have noted natural events that repeat themselves. When people beganto count such events, they began to measure time.在現(xiàn)實(shí)世界中——有時(shí)間的世界中，變化從未停止。有些變化只是偶爾發(fā)生一次，比如月蝕。還有其它重復(fù)發(fā)生的變化，比如日出和日落。人類(lèi)一直在記載自然界中重復(fù)發(fā)生的事件。當(dāng)人們開(kāi)始記載這些事件時(shí)，他們就開(kāi)始測(cè)量時(shí)間了。

In early human history, the only changes that seemed to repeat themselves evenly were themovements of objects in the sky. The most easily seen result of these movements was thedifference between light and darkness. The appearance and disappearance of the sun waseven and unfailing. The periods of light and darkness it created were the first accepted periodsof time. We have named each period of light and darkness—one day.在早期的人類(lèi)歷史中，天體運(yùn)行是唯一有規(guī)律的重復(fù)發(fā)生的變化。而天體運(yùn)行引起的最直觀的結(jié)果就是白天和黑夜的出現(xiàn)。太陽(yáng)樂(lè)此不疲地出現(xiàn)和消失，而此產(chǎn)生的黑白交替的時(shí)段是首次被人們認(rèn)可的時(shí)間。我們把每段白天黑夜的組合稱(chēng)為“一天”。