Gravitational Redshift Puzzle?

📌 CONCEPT: The gravitational redshift of light from a celestial body is related to its mass and radius, causing the frequency of emitted light to decrease as it escapes from the body due to the strong gravitational field.

📐 RULE / FORMULA: According to the theory of general relativity, the gravitational redshift is given by the formula: β = (1 - μ) / μ, where β is the redshift and μ is the gravitational potential at the surface of the celestial body.

💡 WORKED EXAMPLE: Consider a white dwarf with mass M and radius R. If the gravitational potential at its surface is μ = M ∙ R / (4 ∙ π ∙ c ²), then the redshift of light emitted from its surface would be β = (1 - M · R / (4 · π · c ²)) / (M · R / (4 · π · c ²)).

⚠️ COMMON MISTAKE: Students often confuse the gravitational redshift with the Doppler shift, which is a change in frequency due to the relative motion of the source and observer. The gravitational redshift is a consequence of the strong gravitational field of the celestial body, not just the relative motion of the source and observer.