## Imagine that you have obtained spectra for several galaxies and have measured the redshift of each galaxy to determine its speed away from u

Question

Imagine that you have obtained spectra for several galaxies and have measured the redshift of each galaxy to determine its speed away from us. Here are your results: Galaxy 1: Speed away from us is 15000 km/s. Galaxy 2: Speed away from us is 20000 km/s. Galaxy 3: Speed away from us is 25000 km/s. Estimate the distance to each galaxy from Hubble’s law. Assume that H0=22km/(sMly).

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1 week 2021-07-22T16:14:04+00:00 1 Answers 2 views 0

Distance of galaxy 1  = 681.82 Million light years.

Distance of galaxy 2  = 909.09 Million light years

Distance of galaxy 3  = 1136.36 Million light years.

Explanation:

Given that Hubble constant is 22km/s/Mly

Galaxy 1 is speed away from us is 15000km/s

Galaxy 2 is speed away from us is 20000km/s

Galaxy 3 is speed away from us is 25000km/s

We have to find distance to each galaxy from Hubbles law.

According to Hubbles law , when galaxies move away from each other the velocity with which they recede ie the red shift in spectra of distant galaxies  is proportional to the distance.

Distance=Velocity/Hubble constant

Distance of galaxy 1 = =   681.82 Million light years.

Distance of galaxy 2 = = 909.09 Million light years.

Distance of galaxy 3 = = 1136.36 Million light years.