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Black holes aren't perfectly black — they glow faintly with a temperature inversely proportional to their mass.
Counter-intuitively, a less massive black hole has a higher Hawking temperature — a solar-mass black hole radiates at ~60 nanokelvin (far colder than the cosmic microwave background), while a hypothetical mountain-mass black hole would glow white-hot and evaporate in seconds.
A solar-mass black hole would take ~10⁶⁷ years to evaporate — vastly longer than the current age of the universe (1.4 × 10¹⁰ years). Only primordial micro black holes (if they exist) would be small enough to be evaporating observably today.
Hawking temperature (K)
0
T = ℏc³ / (8πGMkB)
What you entered
T = ℏc³ ÷ (8πGMkB)
Hawking formula for M = 1.989e+30 kg= 6.1687e-8 KSchwarzschild radius Rs = 2GM/c²
2 × 6.674e-11 × 1.989e+30 ÷ c²= 2953.9938 mEvaporation lifetime ∝ M³
τ for 1.989e+30 kg= 2.0972e+67 yearsResult
Hawking temperature (K): 0
A black hole of mass 1.989e+30 kg has a Hawking temperature of 6.1687e-8 K and would evaporate in ~2.0972e+67 years.