Hawking temperature (1974) is the temperature at which a black hole radiates as a blackbody:
T_H = ℏc³ / (8πGMk_B) ≈ 6.17×10⁻⁸ K · (M☉/M)
Bekenstein-Hawking entropy: S = k_B A/(4ℓ_P²) — area in Planck units, a profound link between gravity and thermodynamics.
Evaporation time: τ ∝ M³ — a solar-mass BH evaporates in ~2×10⁶⁷ years.
For a Kerr BH, the horizon area A = 8πGM[M + √(M²−a²)]/c², reducing T_H.
The four laws of BH mechanics mirror ordinary thermodynamics exactly.