Black Hole & Black Body Radiation: Why Can't It Absorb?

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A black hole can absorb its own radiation, but only the radiation not directed radially outward can escape its gravitational pull. Radiation emitted from within the event horizon cannot escape, while radiation emitted outside can escape if directed correctly. Hawking radiation is distinct from black body radiation and involves different principles. The closer an object is to the event horizon, the faster it must move to escape, approaching the speed of light. Understanding these dynamics clarifies why black holes interact with radiation in this way.
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why can't a black-hole absorb its own black body radiation? (Black body radiation is also and electro magnetic field like light and so a black-hole with its intense gravitational field is expected not to emit even blackbody radiation also!)
 
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Hi nag555, welcome to physicsforums!
A black-hole does absorb a lot of its own radiation; basically all of it that isn't directed exactly (radially) outward----but the radiation that is directed outward, is able to escape.
 
in that case, any person who jumps on Earth radially outward should also escape gravity!
 
nag555 said:
why can't a black-hole absorb its own black body radiation? (Black body radiation is also and electro magnetic field like light and so a black-hole with its intense gravitational field is expected not to emit even blackbody radiation also!)

Any radiation released inside the event horizon will not escape. Radiation released outside it by in-falling material can escape if it is emitted in the right direction. Hawking radiation is different and is not like black body radiation. See the link in the previous post for information on it.
 
nag555 said:
in that case, any person who jumps on Earth radially outward should also escape gravity!
Why? People can't jump as fast as light...

The closer to an event horizon an object is, the faster it needs to move (for our purposes, in the radial direction) to escape. As the object approaches the event horizon, the escape (radial) velocity approaches the speed of light.
 
thank you for your response...it is clear now..
 

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