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Gravitational Redshift (General Relativity)

Compact Object

Redshift Calculation

Schwarzschild r_s
r_s / R (compactness)
z (gravitational)
Δλ/λ₀
Freq ratio f_obs/f_emit
Time dilation factor

Schwarzschild Metric

ds² = −(1−r_s/r)c²dt²
+ (1−r_s/r)⁻¹dr²
+ r²dΩ²

r_s = 2GM/c² (Schwarzschild radius)

Gravitational redshift:
z = f_emit/f_obs − 1

1+z = √[(1−r_s/r₁)/(1−r_s/r₂)]

Pound-Rebka 1959: Δν/ν = gh/c²
= 2.5×10⁻¹⁵ (22m on Earth)

GPS correction: +45.9 μs/day (GR)
−7.1 μs/day (SR time dilation)