How far is the galaxy from the Earth if it recedes from Earth at a speed v = 0.5 c ? (Use H₀ = 0.022 m/s · lightyear for Hubble's constant.) A) 22.7 lightyears B) 7.2 × 10⁸ lightyears C) 6.8 × 10⁹ lightyears D) 1.3 × 10⁷ lightyears

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Quizplus · Accepted Answer

The distance to the galaxy can be calculated using Hubble's Law: v = H₀ × d. Solving for d gives d = v / H₀. Substituting v = 0.5c (where c is the speed of light, approximately 3 × 10⁸ m/s) and H₀ = 0.022 m/s · lightyear, we find d ≈ 6.8 × 10⁹ lightyears.

How Far Is the Galaxy from the Earth If It