Why are Cepheid variables important to understanding the formation of the Universe?

A) Because they rotate at known speeds.
B) Because their brightness is a function of distance from Earth.
C) Because their luminosity is a function of their pulsation period.
D) Because they are at known distances from Earth.


Ans:
B) Because their brightness is a function of distance from Earth.

C) Because their luminosity is a function of their pulsation period.

Physics & Space Science

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