Is a black hole considred a black body?

In summary, according to current theory, a black hole can be considered a black body due to its emission of Hawking Radiation, which has a black body spectrum. However, it may not satisfy all characteristics of the formal definition of a black body and is not a perfect analogy due to its nature in general relativity.
  • #1
Starwatcher16
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Is a black hole considered a black body?
 
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  • #2
The Hawking Radiation that black holes are supposed to emit (though this hasn't been directly observed yet I believe) has as black body spectrum. In that sense a black hole behaves like a 'black body', although perhaps there are other characteristics of the formal definition of a black body that a black hole does not satisfy? I'm not sure.
 
  • #3
Current theory is that you CAN consider it that way. It just has a really low emissivity coefficient (which also happens to vary with its size) AND all non-rotating black holes of the same size have the same temperature, and rotating ones are hotter.
 
  • #4
Starwatcher16 said:
Is a black hole considered a black body?

As Wallace and fleem have noted, Hawking showed that black holes radiate in (close to) black body-like fashion. Taking a black hole to be a black body and using some hand waving leads to

https://www.physicsforums.com/showthread.php?t=205711.
 
  • #5
It's really not a good analogy. A blackbody is an entity in classical physics. A black hole is a construct of general relativity. It posseses some of the same properties, but is not of the same species.
 

Related to Is a black hole considred a black body?

1. What is a black hole?

A black hole is a region in space where the gravitational pull is so strong that nothing, including light, can escape it. It is formed when a massive star collapses under its own gravity.

2. What is a black body?

A black body is an idealized object that absorbs all radiation that falls on it and emits thermal radiation at all wavelengths. It is often used as a theoretical reference for studying the properties of real objects, such as stars.

3. How is a black hole related to a black body?

A black hole is considered a black body because it absorbs all radiation that falls on it and emits thermal radiation at all wavelengths, just like a black body. However, the radiation emitted by a black hole is known as Hawking radiation and is caused by quantum effects near the event horizon, rather than the thermal radiation emitted by a black body.

4. Can we observe a black hole's thermal radiation?

No, we cannot observe a black hole's thermal radiation directly because the event horizon of a black hole prevents any radiation from escaping. However, we can indirectly observe the effects of the radiation, such as the evaporation of smaller black holes and the distortion of space-time around larger black holes.

5. Why is it important to study whether a black hole is a black body?

Studying whether a black hole is a black body can help us understand the fundamental principles of physics, such as the relationship between gravity and quantum mechanics. It can also provide insights into the behavior of matter and radiation in extreme conditions, which can help improve our understanding of the universe.

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