A galaxy's spectrum has a redshift of 30,000 kilometers per second. If the Hubble constant is 75 kilometers per second per megaparsec, how far away from Earth is the galaxy? A) 10⁶ megaparsecs B) 1,000 megaparsecs C) 20 megaparsecs D) 50 megaparsecs E) 400 megaparsecs

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Quizplus · Accepted Answer

The distance to the galaxy can be calculated using Hubble's Law: velocity = Hubble constant × distance. Rearranging gives distance = velocity / Hubble constant = 30,000 km/s / 75 km/s/Mpc = 400 Mpc.

A Galaxy's Spectrum Has a Redshift of 30,000 Kilometers Per