Do Black Holes Actually Possess Entropy?

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Discussion Overview

The discussion revolves around the concept of entropy in black holes, particularly questioning how black holes can possess entropy given the challenges in understanding their interior and the nature of microstates. The scope includes theoretical considerations and conceptual clarifications related to black hole thermodynamics.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how black holes can have entropy if their interiors are inaccessible and unknown, suggesting that this might imply low entropy instead of high.
  • Another participant argues that black holes have very high entropy due to their ability to absorb mass and energy, leading to a continuous increase in entropy based on thermodynamic principles.
  • A participant references the holographic principle in relation to understanding black hole entropy, indicating an interest in deeper theoretical frameworks.

Areas of Agreement / Disagreement

Participants express differing views on the nature of black hole entropy, with some asserting it is high due to absorption capabilities, while others question the validity of this claim based on the lack of knowledge about microstates.

Contextual Notes

The discussion highlights limitations in understanding black hole entropy, particularly regarding assumptions about microstates and the implications of black hole thermodynamics. There are unresolved questions about the relationship between the definition of black holes and their entropy.

Who May Find This Useful

This discussion may be of interest to those exploring black hole thermodynamics, entropy in physical systems, and the implications of theoretical physics concepts like the holographic principle.

brcooke
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Hi, I'm not a physicist so the answer to this question may be elementary but I can't figure it out for myself:

Black holes are famous because (almost) nothing can escape from them. Once an observer has crossed the event horizon, no more contact may be made with him or her. Thus it will forever be impossible to know what the interior of a black hole is like, because observers that go inside will never be able to communicate with us.

Everyone knows that the entropy of a black hole is proportional to its area, and that there are only 3 parameters necessary to describe a black hole: its area, charge, and spin (right?). All of the books I've read about the subject say that astronomical-scale black holes have very high entropy (the exception being very small black holes created in the lab).

Now, my understanding of entropy is that it is proportional to the logarithm of the number of microstates that could underlie a single macrostate. My question is: Since it is impossible to know anything about the interior of a black hole, and thus anything about the microstates within it, how can black holes have entropy at all? And contrary to the popular assumption that the entropy of black holes is very large, given how easy it is to define a black hole, shouldn't that indicate that their entropy is in fact very low?

Thanks for your help!

Brad.
 
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No, I haven't, but I'm deep into the holographic principle as suggested. I will check that next. Thanks!
 
I think that entropy of black hole is very high due to its capability of absorbing everything. Talking at macroscopic level, if we consider black hole as a system, then mass as well as heat in form of radiations are going into the system and not coming outside.
So, if we use the relation of entropy balance:
S in - S out + S gen = dS sys
S out=0 and S gen is positive
Thus Change in entropy of system(R.H.S) is positive.
Therefore we can say that the entropy of black holes is increasing continuously at a high rate meaning that it has very high entropy
 

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