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Hawking radiation
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Black holes emit thermal radiation.
T = ħc³/8πGMkQuantum effects near the horizon give black holes a temperature T = ħc³/(8πGMk_B) and slow evaporation. A solar-mass hole has 60 nK.
Smaller holes are hotter and evaporate faster.
Not yet observed.
In more detail
Hawking radiation is a predicted thermal emission from black holes, arising from quantum effects near the event horizon. It implies that black holes slowly lose mass over time.
Real-world uses
- Hawking radiation is a key idea linking quantum theory and gravity.
- It is studied in analogue experiments.
- Theoretical physicists use Hawking radiation to study how quantum mechanics and gravity combine.
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Frequently asked questions
Has Hawking radiation been observed?
Not directly from astrophysical black holes, because it is extremely weak.
What does it imply for black holes?
They can slowly evaporate, though this takes an enormous time for stellar black holes.
Will black holes evaporate?
In theory, yes, very slowly, and the rate depends on the black hole's mass; large black holes lose energy far too slowly to matter in practice.
Related topics in Relativity
Geodesics · Schwarzschild metric · Black hole event horizon · Gravitational waves detection · Frame dragging · Light bending by the Sun