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cragar
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if light cannot escape a black hole then how do they emit stuff called hawking radiation.
You are wrong for using the word real in the first place. Funky rightly said virtual ( because we haven't of cannot directly observed them). The fact is, they are created near the mouth of the black hole and one has negative while the other has positive energy(this I believe is principally not to violate the conservation of energy).The one with the posite energy is what we see as the radiation. The one with with negative energy falls in and reduces the black hole's energy. This in turn reduce the mass of the black hole since the mass is proportional to the energy of the black hole. reduction in mass means increase in temperature which further speeds up radiation and the black hole eventually evaporates.FrankPlanck said:If the gravitational tidal force does a work equal to 2mc^2 (mc^2 is the mass-energy of a particle) BH can create two real particles (a particle and an antiparticle) in the vicinity of schwarzschild radius. Since these particles are created outside it's possible that one of these fall into the BH whereas the other escape. In this case BH has lost mc^2 of mass-energy (the escaping particle) (hence temperature (which is proportional to 1/(BH mass)) increases) and BH radiates.
Note that this is a very semplified treatment, in reality things are more complicated.
Abbas Sherif said:You are wrong for using the word real in the first place. Funky rightly said virtual ( because we haven't of cannot directly observed them). The fact is, they are created near the mouth of the black hole and one has negative while the other has positive energy(this I believe is principally not to violate the conservation of energy).The one with the posite energy is what we see as the radiation. The one with with negative energy falls in and reduces the black hole's energy. This in turn reduce the mass of the black hole since the mass is proportional to the energy of the black hole. reduction in mass means increase in temperature which further speeds up radiation and the black hole eventually evaporates.
Hawking Radiation is a theoretical phenomenon proposed by physicist Stephen Hawking in the 1970s. It is a form of radiation that is believed to be emitted by black holes, causing them to gradually lose mass and eventually evaporate.
Hawking Radiation is based on the concept of virtual particles, which are constantly popping in and out of existence in empty space. When this happens near the event horizon of a black hole, one of the particles may fall into the black hole while the other escapes as radiation.
At this time, Hawking Radiation has not been directly observed. Its effects are too small to be detected by current technology, and it is theorized that it would only be observable from black holes with extremely low mass.
Hawking Radiation is significant because it provides a potential mechanism for black holes to eventually evaporate, which was previously thought to be impossible. It also has implications for the fundamental principles of physics, such as the conservation of energy.
While there is strong theoretical and mathematical evidence for Hawking Radiation, it has not yet been proven through direct observation. However, it is widely accepted in the scientific community and has been a topic of ongoing research and study.