1 "Time is an illusion. Lunchtime doubly so," joked Douglas Adams in The Hitchhiker's Guide to the Galaxy. Scientists aren't laughing, though. Some speculative new physics theories suggest that time emerges from a more fundamental-and timeless-reality.

    2 Try explaining that when you get to work late. The average U.S. city commuter loses 38 hours a year to traffic delays.

    3 Wonder why you have to set your clock ahead in March? Daylight Saving Time began as a joke by Benjamin Franklin, who proposed waking people earlier on bright summer mornings so they might work more during the day and thus save candles. It was introduced in the U.K. in 1917 and then spread

    4 Green days. The Department of Energy estimates that electricity demand drops by 0.5 percent during Daylight Saving Time, saving the equivalent of nearly 3 million barrels of oil.

    5 By observing how quickly bank tellers made change, pedestrians walked, and postal clerks spoke, psychologists determined that the three fastest-paced U.S. cities are Boston, Buffalo, and New York.

    6 The three slowest? Shreveport, Sacramento, and L.A.

    7 One second used to be defined as 1/86,400 the length of a day. However, Earth's rotation isn't perfectly reliable. Tidal friction from the sun and moon slows our planet and increases the length of a day by 3 milli-seconds per century.

    8 This means that in the time of the dinosaurs, the day was just 23 hours long.

    9 Weather also changes the day. During El Ni?o events, strong winds can slow Earth's rotation by a fraction of a milli-second every 24 hours.

    10 Modern technology can do better. In 1972 a network of atomic clocks in more than 50 countries was made the final authority on time, so accurate that it takes 31.7 million years to lose about one second.

    11 To keep this time in sync with Earth's slowing rotation, a "leap second" must be added every few years, most recently this past New Year's Eve.

    12 The world's most accurate clock, at the National Institute of Standards and Technology in Colorado, measures vibrations of a single atom of mercury. In a billion years it will not lose one second.

    13 Until the 1800s, every village lived in its own little time zone, with clocks synchronized to the local solar noon.

    14 This caused havoc with the advent of trains and timetables. For a while watches were made that could tell both local time and "railway time."

    15 On November 18, 1883, American railway companies forced the national adoption of standardized time zones.

    16 Thinking about how railway time required clocks in different places to be synchronized may have inspired Einstein to develop his theory of relativity, which unifies space and time.

    17 Einstein showed that gravity makes time run more slowly. Thus airplane passengers, flying where Earth's pull is weaker, age a few extra nano-seconds each flight.

    18 According to quantum theory, the shortest moment of time that can exist is known as Planck time, or 0.0000000000000000000000000000000000000000001 second.

    19 Time has not been around forever. Most scientists believe it was created along with the rest of the universe in the Big Bang, 13.7 billion years ago.

    20 There may be an end of time. Three Spanish scientists posit that the observed acceleration of the expanding cosmos is an illusion caused by the slowing of time. According to their math, time may eventually stop, at which point everything will come to a standstill.

    1、時(shí)間是什么？--英國(guó)著名科幻小說家道格拉斯·亞當(dāng)斯在他的小說《銀河系漫游指南》中開玩笑地說："時(shí)間就是一種幻覺，午餐時(shí)間就更不用說了。"可是，科學(xué)家卻笑不出來。最新的一些物理學(xué)理論猜想認(rèn)為，時(shí)間起源于某種更根本、同時(shí)也就不存在時(shí)間的一種實(shí)體。

    2、上班遲到的時(shí)候，怎么給自己找借口？--美國(guó)人平均每年因交通問題而延誤的時(shí)間大約為38小時(shí)。

    3、為什么每年都要從三月份開始實(shí)行夏時(shí)制？--300年前，美國(guó)天才政治家、科學(xué)家本杰明·富蘭克林（Benjamin Franklin）的一個(gè)玩笑開大了：他說，夏日時(shí)期，天一早就大亮了，應(yīng)該早點(diǎn)兒把人們叫醒，讓他們?cè)琰c(diǎn)出去干活，這樣不但可多干活，還能節(jié)約幾根蠟燭。沒想到英國(guó)人從1917年開始就把他的玩笑變成現(xiàn)實(shí)，并在全世界迅速推廣開來。

    4、為什么實(shí)行夏時(shí)制的日子被稱為"綠色日子"?--美國(guó)能源部統(tǒng)計(jì)，實(shí)行夏時(shí)制期間，美國(guó)能源需求量下降0.5%,相當(dāng)于節(jié)省了300萬桶石油。

    5、美國(guó)哪三座城市人們的動(dòng)作最快？--心理學(xué)家通過觀察銀行出納員找零錢的動(dòng)作、行人的步伐速度和郵電行業(yè)工作人員的說話速度，判定人們動(dòng)作最快的三座城市是：波斯頓、水牛城和紐約。

    6、那動(dòng)作最慢的又是哪些城市？--什里夫波特（美國(guó)路易斯安那州西北部城市）、薩克拉門托（加州首府）和洛杉磯。

    7、一天的86400分之一就是一秒嗎？--不一定！因?yàn)榈厍虻淖赞D(zhuǎn)并不是你想象的那么靠譜。由于太陽和月亮的牽引會(huì)產(chǎn)生潮汐現(xiàn)象，而潮汐會(huì)產(chǎn)生一定的摩擦力，使地球的自轉(zhuǎn)速度逐漸降低，大約每過一百年，一天時(shí)間就會(huì)慢3毫秒。

    8、恐龍時(shí)代一天有幾個(gè)小時(shí)？--根據(jù)上述算法，那個(gè)年代，一天只有23個(gè)小時(shí)。

    9、天氣現(xiàn)象會(huì)影響時(shí)間嗎？--天氣也會(huì)對(duì)時(shí)間造成一定影響。在厄爾尼諾現(xiàn)象期間，暴風(fēng)會(huì)使地球的自轉(zhuǎn)速度慢下來，大約是每24小時(shí)減慢一個(gè)毫秒的幾分之一。

    10、原子鐘的準(zhǔn)確程度有多高？--現(xiàn)代技術(shù)取得了長(zhǎng)足進(jìn)展。1972年，全世界共有50多個(gè)國(guó)家共建起一個(gè)原子計(jì)時(shí)網(wǎng)絡(luò)，該網(wǎng)絡(luò)就成為全世界最大的時(shí)間權(quán)威，其準(zhǔn)確度達(dá)到每3170萬年相差一秒左右。

    11、什么是閏秒？--為了使時(shí)間與地球自轉(zhuǎn)速度的減慢相一致，每隔幾年就要給某一天的時(shí)間延長(zhǎng)1秒鐘，這就是閏秒。最近一次調(diào)整是去年除夕（即2008年12月31日24:00）,那一天要比平時(shí)多出一秒鐘。

    12、世界上什么東西的時(shí)間最精確？--美國(guó)設(shè)在科羅拉多州的國(guó)家標(biāo)準(zhǔn)與技術(shù)研究所，用世界上最準(zhǔn)確的時(shí)鐘測(cè)算出單個(gè)汞原子的震動(dòng)頻率最為精確，每十億年才差別一秒鐘，因此汞原子的震動(dòng)時(shí)間最準(zhǔn)確。

    13、美國(guó)什么時(shí)候才開始劃分時(shí)區(qū)？--應(yīng)該是在19世紀(jì)初的時(shí)候。因?yàn)榇饲懊绹?guó)的每個(gè)村落都是以當(dāng)?shù)厝债?dāng)正午的時(shí)候來確定時(shí)間的，所以那時(shí)候一個(gè)村子就有自己的一個(gè)微小時(shí)區(qū)，而不是現(xiàn)在的全國(guó)幾個(gè)時(shí)區(qū)。

    14、在還沒有劃分時(shí)區(qū)的時(shí)候，美國(guó)鐵路運(yùn)輸有什么問題？--那時(shí)候簡(jiǎn)直亂套了，火車進(jìn)出站時(shí)間亂套了，時(shí)刻表簡(jiǎn)直成了擺設(shè)，后來只好沿途設(shè)立時(shí)間告示牌，以區(qū)分出發(fā)地時(shí)間、目的地時(shí)間和"鐵路時(shí)間"的不同。

    15、1883年11月18日，美國(guó)各大鐵路公司成功迫使政府采用時(shí)區(qū)制。

    16、也許正是由于人們總在思考怎樣用一個(gè)統(tǒng)一時(shí)間把不同地方的時(shí)間同步化的問題，才激發(fā)了愛因斯坦的靈感，產(chǎn)生了相對(duì)論，徹底統(tǒng)一了時(shí)空問題。

    17、愛因斯坦通過計(jì)算，表明引力的存在會(huì)使時(shí)間過得慢一些，因此，乘坐飛機(jī)的旅客，由于在空中的地心引力要弱一些，結(jié)果每一次飛行，旅客就年輕幾個(gè)微秒（原文說老了幾個(gè)微妙，應(yīng)該是作者自己沒有倒過來的緣故--譯者注）.

    18、根據(jù)量子理論，能夠存在的最小時(shí)間單位叫做普朗克時(shí)間，長(zhǎng)度為0.0000000000000000000000000000000000000000001秒（一千億億億億億分之一秒）.

    19、時(shí)間并非一直都存在。大多數(shù)科學(xué)家相信時(shí)間就是誕生宇宙的大爆炸那一刻才開始有的，即137億年前才有時(shí)間的存在。

    20、時(shí)間也還有可能結(jié)束。西班牙有三名科學(xué)家提出假說認(rèn)為，現(xiàn)在人們所觀察到的宇宙膨脹現(xiàn)象，實(shí)質(zhì)上是因?yàn)闀r(shí)間變慢而產(chǎn)生的假象。按照他們提供的數(shù)學(xué)模型計(jì)算，時(shí)間終歸是會(huì)停止的，在那一時(shí)刻，一切就都停止了（同時(shí)宇宙也將不復(fù)存在，一切幻化為零--譯者注。）