Hawking radiation temperature -- observer dependent?

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Discussion Overview

The discussion revolves around the temperature of Hawking radiation and its dependence on the observer's position relative to a black hole. Participants explore the implications of measuring temperature from different distances, the relationship between Hawking radiation and Unruh radiation, and the concept of a black hole firewall.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question who measures the temperature of Hawking radiation and suggest that redshift effects could lead to a lower temperature measurement from a distance.
  • It is proposed that the Hawking temperature is measured by an observer far from the horizon, while an observer near the horizon would perceive a higher temperature.
  • There is a suggestion that the temperature measured at the event horizon could be infinite, but this might be regularized to a large finite number.
  • Some participants connect the concept of increased temperature at the horizon to the idea of a black hole firewall.

Areas of Agreement / Disagreement

Participants express differing views on the nature of temperature measurements related to Hawking radiation, with no consensus reached on the implications of observer position or the definition of temperature at the event horizon.

Contextual Notes

Participants note the potential for redshift to affect temperature measurements and the implications of observer acceleration on radiation perception, but these aspects remain unresolved.

bcrelling
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Black holes are claimed to radiate at a temperature corresponding to the hawking radiation. But who is measuring the temperature? If the radiation is measured from far away the red shift will indicate a lower temperature won't it?

Is the temperature given by the formula as measured from a hypothetical probe suspended at the event horizon? If so, will the proper acceleration of the probe experience unruh radiation too, or in this case would they be one and the same thing(unruh and hawking radiation)?
 
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There is an absolute temperature scale.
 
Hawking temperature is the temperature measured by an observer far away from the horizon. An observer close to the horizon will see a higher temperature.
 
Demystifier said:
Hawking temperature is the temperature measured by an observer far away from the horizon. An observer close to the horizon will see a higher temperature.

Would the increased temperature as measured by an observer at the horizon be definable?

Is this where the idea of the black hole fire wall comes from?
 
bcrelling said:
Would the increased temperature as measured by an observer at the horizon be definable?
It would be infinite, but infinity can be replaced by a large finite number by appropriate regularization.

bcrelling said:
Is this where the idea of the black hole fire wall comes from?
It is closely related to it.
 

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