Where does this come from, and can I check it?

The slower a Cepheid pulses, the more light it truly gives out. The figure is taken from NASA Science, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

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Yes. It sits on the Space shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

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The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

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Leavitt found a yardstick in Cepheid stars

The slower a Cepheid pulses, the more light it truly gives out Henrietta Swan Leavitt spotted the relation around 1908 while cataloguing variable stars in the Magellanic Clouds, where all the stars lie at similar distance. Because apparent brightness then reflected true brightness, a Cepheid's pulse rate revealed its luminosity. Hubble used the rule to show that Andromeda lies far beyond the Milky Way. It sits in Mondo's space collection, one of 200 facts that each trace back to the reference below.

Where this comes from

NASA Science

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Tags: cepheid, distance, leavitt

Leavitt found a yardstick in Cepheid stars: the short answers

Where does this come from, and can I check it?: The slower a Cepheid pulses, the more light it truly gives out. The figure is taken from NASA Science, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a space fact?: Yes. It sits on the Space shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.