Discussion Overview
The discussion revolves around the nature of black hole horizons, particularly in the context of Hawking radiation and the implications of black hole evaporation. Participants explore the perspectives of distant and falling observers, the formation of event horizons, and the compatibility of General Relativity with black hole evaporation.
Discussion Character
- Debate/contested
- Technical explanation
- Conceptual clarification
Main Points Raised
- Some participants assert that for a distant observer, the formation of the black hole horizon is not part of their future light cone, while others challenge this view, suggesting that it can be included depending on the observer's trajectory.
- There is contention regarding whether an evaporating black hole possesses a true event horizon or merely an apparent horizon, with some arguing that Hawking radiation originates from above the horizon rather than at it.
- Participants express uncertainty about the appropriate metrics to describe evaporating black holes, with references to the Vadiya metric and its limitations.
- Some argue that the model of General Relativity with a static horizon is incompatible with the concept of a black hole that forms and evaporates over time.
- There are differing opinions on the implications of horizon formation and evaporation for distant observers, with some suggesting that the horizon never forms for them, while others maintain that it does enter their future light cone eventually.
Areas of Agreement / Disagreement
Participants do not reach a consensus on the nature of black hole horizons, the implications of Hawking radiation, or the appropriate metrics for describing evaporating black holes. Multiple competing views remain throughout the discussion.
Contextual Notes
Limitations include unresolved questions about the metrics for evaporating black holes, the definitions of event versus apparent horizons, and the implications of different spacetime models on the understanding of black hole evaporation.