An astronomer at Harvard College, Henrietta Leavitt, had discovered that these periods of brightness could be used to measure the star's distance from Earth.

VOA: special.2009.04.29

So what we do is we pick an origin, call it zero, we put some markers there to measure distance, and we say this guy is sitting at 1,2,3,4,5.

我们现在选择一个原点,称其为零点,我们做一些标记来测量距离,这个点在五个单位长度的地方

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But if we could statistically control for every other variable, all I'd need to do is measure the distance from your door to everybody else's door on campus and I could chart out who's going to fall in love with whom on the Yale campus.

如果我们能精确地控制其他可变因素，那么只需要测测距离,你宿舍门到其他宿舍门的距离,我就能够计算出,校园里谁爱上了谁。

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