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The higher up you are, the faster time passes - by bringing relativity back to Earth.
Past experiments have confirmed Albert Einstein's theory of relativity by comparing atomic clocks on the Earth's surface with ones placed in high-altitude jets and rockets.
But ABC Science reported on September 22 that Dr James Chin-Wen Chou and colleagues from the National Institute of Standards and Technology (NIST) in the US, have used the latest generation of atomic clocks to measure changes in time at a more down-to-Earth scale.
The researcher's first experiment involved lifting one clock above the other allowing them to measure the change in the Earth's gravitational pull over distances of less than a meter.
Their results confirmed time moves quicker, and hence a person ages faster, when they stand a couple of steps higher on a staircase.
The difference isn't much, about 25 billionths of a second over a 79 year life time, but it will have more practical applications in areas like global positioning systems and geophysics.
The key to both experiments is the quantum logic atomic clock, which uses the oscillation of a single aluminium ion to maintain precise timing. The atom vibrates between two energy levels allowing the clocks accuracy down to a second in 3.7 billion years.
參考譯文：
如果把相對論應用到地球上來，你站的越高，時間流逝得越快。
以往的試驗論證了艾爾波特•愛因斯坦的相對論，試驗將地面上的原子鐘和高空火箭和噴氣式飛機上的原子鐘進行比較。
美國國家標準與技術研究院物理實驗室的詹姆斯•周欽文（音譯）教授和同事一起，用最新一代的原子鐘在較為接近地面的位置測量時間的流逝。
在第一項試驗中，研究人員將兩個鐘分別放在距離不到一米的地方，在地球引力作用下測量時間的流逝。
結果再次證明，對于站在比地面高幾個階梯的樓梯上的人來說，時間過得越快，他們也要比站在地面的人們衰老更快。
當然，這種衰老速度差異微乎其微。在一個人79年的生命中，可能才只有250億分之一秒的差別。但是卻可以應用于全球定位系統(tǒng)和地球物理學等領域中。
兩個實驗的重點是量子鋁原子鐘，它利用單一鋁離子的震蕩來精準測量時間的流逝。原子在兩個能量等級之間震蕩，鐘的精確度為運行37億年后誤差不超過正負一秒。
