The Night Sky, Explainedby Dmitry Shteynbuk
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How stars workDefinedTerm

Cepheid variable

A pulsating giant star whose period reveals its true luminosity.

Henrietta Leavitt discovered the period–luminosity relation in 1912. It underpins the extragalactic distance scale.

Used in these guides

  • How Far Is Far: The Cosmic Distance LadderBeyond the Sun
  • Hubble, Leavitt, and the Night the Universe Got BiggerHow we learned where we are
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