For 100 years astronomers have paid particular attention to a class of variable star known as the Cepheids.

过去100年来，天文学家特别注意一类称作“仙王座变光星”的恒星。

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And, since individual Cepheids are bright enough to be seen in other galaxies, they were the first tool used to estimate the distances to such galaxies.

且由于在另一个星系中的单颗“造父变星”的亮度就足于使其被观测到，所以它们是测算类似星系距离的首选工具。

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Cepheids are a special type of star that pulsates in a predictable way, and like the type 1a supernova, they are assumed to be the same, no matter where they are located.

造父是种特殊的恒星，它能以可以预测的方式周期脉动，就像I型超新星，他们被当做是一样的，不管他们在那里。

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Certain rare stars, known as Cepheids, grow brighter and fainter at a regular rate.

ECONOMIST: Twirls and swirls from outer space

In addition, Miss Leavitt discovered around 2, 400 Cepheids, about half of those known in her day.

ECONOMIST: Twirls and swirls from outer space

Shapley saw evidence for Cepheids in Andromeda long before Hubble did, but refused to believe they could be Cepheids out of a stubborn attachment to his own theories.

ECONOMIST: Twirls and swirls from outer space