Can Radiation from Black Holes Travel Faster than Light?

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Discussion Overview

The discussion revolves around the nature of radiation emitted by black holes, specifically questioning whether this radiation can travel faster than the speed of light. Participants explore concepts related to black hole physics, including Hawking radiation, the event horizon, and the implications of Einstein's theory of relativity.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants express confusion about the relationship between black holes, radiation, and the speed of light, questioning if radiation escaping a black hole could exceed this limit.
  • It is noted that Hawking radiation is a specific type of radiation that does not enter the event horizon but is created at it, and it does not travel faster than the speed of light.
  • Participants clarify that Hawking radiation involves virtual particle pairs, where one particle falls into the black hole while the other escapes, contributing to the black hole's temperature.
  • Some participants provide links to external resources for further reading on Hawking radiation and related topics.
  • There is a discussion about accessing articles related to black holes, with some participants attempting to share links and others expressing difficulties in accessing them.

Areas of Agreement / Disagreement

Participants generally agree that Hawking radiation does not travel faster than the speed of light and is produced outside the event horizon. However, there remains uncertainty regarding the implications of this radiation and the conditions under which it occurs.

Contextual Notes

Some participants mention that the discussion involves complex concepts that may be outside their field of expertise, indicating a potential limitation in understanding the nuances of Hawking radiation and black hole physics.

Who May Find This Useful

This discussion may be of interest to high school students and enthusiasts of astrophysics, particularly those curious about black holes and the theoretical implications of radiation in relation to the speed of light.

lostinaworld
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Hi, I'm at high school at the moment and i have gotten really interested in black holes and the way they work as i have been reading books from Stephen Hawking.

So we know that black holes absorb matter and photons by the pull of gravity. And we also know that it emmits radiation. But because photons can't escape the pull and radiation can, does that mean the radiation should be traveling faster than the speed of light? It says that for something to escape a black hole it should be traveling faster than the speed of light. However this is incompatible with einsteins theory of relativity because he says that nothing can exceed the limit of the speed of light. Could the uncertainty principle make this possible?
 
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lostinaworld said:
Hi, I'm at high school at the moment and i have gotten really interested in black holes and the way they work as i have been reading books from Stephen Hawking.

So we know that black holes absorb matter and photons by the pull of gravity. And we also know that it emmits radiation. But because photons can't escape the pull and radiation can, does that mean the radiation should be traveling faster than the speed of light? It says that for something to escape a black hole it should be traveling faster than the speed of light. However this is incompatible with einsteins theory of relativity because he says that nothing can exceed the limit of the speed of light. Could the uncertainty principle make this possible?

Photons are radiation. The radiation that "escapes" a black hole is a special kind called Hawking radiation. He says that it is hard to explain. So I don't even try to understand it.
 
This doesn't really answer my question though because your telling me about this special hawking radiation (i know the name anyway) i asked if the radiation escaping could be faster than the speed of light.
 
Hawking radiation does not enter the event horizon but is created at it. It doesn't travel faster than the speed of light. It's creation is something to do with virtual particles becoming real I think but this is outside my field. Hopefully someone more informed can help you with a more thorough answer.
 
Light = electromanetic radiation = photons. They're the same thing.
You're asking if light can travel faster than light.


Hawking radiation(so, photons) is emitted from above the event horizon, so it does not violate the speed limit.
 
Thankyou
 
Ryan_m_b said:
Hawking radiation does not enter the event horizon but is created at it. It doesn't travel faster than the speed of light. It's creation is something to do with virtual particles becoming real I think but this is outside my field. Hopefully someone more informed can help you with a more thorough answer.

By virtual particles, do you mean particle pairs that annihilate each other?
 
yes Hawking radiation is a form of virtual particle pair production that occurs outside the EH. One of the pairs falls into the EH, the other acts as a blackbody temperature.

this thread contains some information on Hawking radiation including when Hawking radiation takes effect as it only occurs during specific conditions discussed in this thread.


https://www.physicsforums.com/showthread.php?t=683377


this site contains some info on Hawking radiation

http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/hawking.html

here is a pdf copy of Hawking paper

http://www.itp.uni-hannover.de/~giulini/papers/BlackHoleSeminar/Hawking_CMP_1975.pdf

another interesting aticle is this one
http://arxiv.org/abs/1009.0633

edit I should be more precise here Blackhole evaperation only occurs under certain conditions.
 
Last edited:
I'm not sure if this is relevant to this topic yet,
I have not read it but i plan on it later today but,
in sky and telescope there's an article,

sky and telescope magazine
june 2013
" when black holes eat stars "
pg.16

I have a direct link to the digital magazine article if wanted.
just let me know.
 
  • #10
Yes please :)
 
  • #11
lostinaworld said:
Yes please :)

I'm a subscriber to the magazine,so let me know if you can not access this, i tested it, it works, but I'm not sure if it is because I'm a subscriber, so let me know if it does or doesn't work.

http://www.nxtbook.com/nxtbooks/newtrack/st_201306/#/18
 
  • #12
It doesn't work but thanks anyway :)
 
  • #13
lostinaworld said:
It doesn't work but thanks anyway :)

hmm.. i'll try to find another posting about it..
the only other thing i can suggest is, maybe go to the grocery store and find the magazine on the self and read it from there..
but I'm not sure if it is out on stands yet...

sorry.
 
  • #14
Im a subscriber to all about space magazine. Thats how i came about black holes and other stuff
 

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