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Home Q & A Board Science-Related Homework Help Physics
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Tsync Tsync
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8 years ago
Why does the Cepheid "standard candle" have limited usefulness beyond 20 Mpc?
A) Distant galaxies are so young they do not contain Cepheids.
B) Older distant Cepheids are of Population II, where the period-luminosity relation no longer works.
C) Cepheids are too faint to be seen beyond that distance, even with HST.
D) The light variability of Cepheids diminishes with distance so they do not appear to vary there.
E) Distant galaxies are seen in the past, when Cepheid variables behaved differently than they do today.
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Astronomy Today

Astronomy Today


Edition: 8th
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Minoring in physics
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RatatouilleRatatouille
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Tsync Author
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8 years ago
You answered my question so timely, I really value that, thank you
Minoring in physics
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8 years ago
Slight Smile
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