Recall That Hubble's Law Is Written V = H₀d, Where $\left[20 \frac{\mathrm{km} / \mathrm{s}}{\mathrm{Mly}}\right]$

question 44

Essay

Recall that Hubble's law is written v = H₀d, where v is the recession velocity of a galaxy located a distance d away from us, and H₀ is Hubble's constant. Suppose H₀ = 20 km/s/Mly. How fast would a galaxy located 1375 Mly distant be receding from us? Show all work clearly, and state your final answer with a complete sentence. Give the speed both in units of kilometers per second and as a percentage of the speed of light.
v = H₀d = (1375 Mly)
$\left[20 \frac{\mathrm{km} / \mathrm{s}}{\mathrm{Mly}}\right]$
= 27,500
$\frac{\mathrm{km}}{\mathrm{s}}$
= 0.09c

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