Can Black Holes Decay and How Does This Affect Their Event Horizon?

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Discussion Overview

The discussion revolves around the decay of black holes and its implications for their event horizons. Participants explore theoretical aspects of black hole dynamics, particularly in relation to particle-antiparticle interactions and energy considerations.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant references a source suggesting that black holes can decay but questions how this affects the event horizon when particles are absorbed and ejected.
  • Another participant argues that the escape of a particle from a particle-antiparticle pair results in a net loss of energy from the black hole, implying that the black hole loses mass.
  • A different viewpoint emphasizes the ambiguity of the term "nothing" in the context of energy and particle creation, suggesting that particle-antiparticle pairs arise from the energy-density of the vacuum rather than true nothingness.
  • One participant elaborates that the process of particle-antiparticle creation near the event horizon involves complex interactions with spacetime, leading to a decrease in the black hole's mass and a corresponding shrinkage.
  • Another participant asserts that nothing is ejected from black holes, claiming that matter is destroyed at the core and that the event horizon remains mostly unchanged, though it can vary under certain conditions.

Areas of Agreement / Disagreement

Participants express differing views on the nature of black hole decay and the behavior of the event horizon, indicating that multiple competing perspectives remain without consensus.

Contextual Notes

Participants discuss the definitions of energy and "nothing," as well as the implications of local versus global effects in the context of black holes, highlighting the complexity of the topic without resolving these nuances.

Haibara Ai
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http://www.superstringtheory.com/blackh/blackh3.html
the URL above says that black holes can decay, but I don't understand, if the black hole sucks in an antiparticle and the particle gets ejected in the opposite direction, doesn't the event horizon of the black hole stay the same? How does it get smaller??

Thanks
 
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The problem is that those particle/antiparticle pairs are energy from nothing. Normally they would destroy each other and there would be no net loss or gain. However, when one is pulled into a black hole, and its pair escapes then the one that got away is new matter from nothing. Since this matter must come from somewhere it comes from the black hole.
 
well it depends on what you mean by "nothing", which semantic use of "nothing" you anticipate here.. it is not nihilo, it is the energy-density, vacuum of particles which creates particle-antiparticle pair.s
 
Haibara Ai said:
How does it get smaller??
One must be careful here with the definition of energy. The process of particle-antiparticle creation near the event horizon is defined locally. But then, one must look at the global effect, where spacetime is no longer flat as was approximately used in the previous setting, locally near the event horizon. It turns out that the black hole sucks in negative energy and spits out at infinity positive energy. So its mass deos decrease, and therefore it does shrink.
 
Actually, nothing gets ejected form black holes, what happens, is that all matter that gets sucked up by the black hole goes into the black hole's center or core where it gets destroyed. Also, about the event horizon: most of the time it stays the same, but depnding on what is going on around it, it can change. For more information look at my post, why white holes don't exist. It will explain why black holes are one way.
 

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