4 ms·
True, but from the point of view of an observer at infinity, the baryon falls and comes to a halt, while the event horizon of the black hole expands and encompa
by qubex 6y ago
True, but from the point of view of an observer at infinity, the baryon falls and comes to a halt, while the event horizon of the black hole expands and encompasses it (or would, if you could measure the diameter of the black hole with sufficient precision).
This is just the essence of the information paradox, expressed in terms of baryon and lepton numbers. Either the Hawking radiation that comes out is ‘correlated’ with the matter that fell in (meaning that black holes have hair) and information is preserved, or they’re not, and information is destroyed. That’s literally the crux of the matter.
- simonh 6y agoThat’s a good point, I wasn’t thinking about it in terms of the information paradox, but then the recently proposed solutions look like they have a good chance of panning out. https://en.wikipedia.org/wiki/Black_hole_information_paradox#Recent_developments https://en.wikipedia.org/wiki/Black_hole_information_paradox... But anyway I still don’t think this is really an issue regardless. The same could be said of the cosmic event horizon. Vast swathes of the universe are unobservable and causally disconnected from us due to the expansion of the universe separating us at faster than the speed of light. Again, no Baryons are being destroyed in this process, they’re just becoming unobservable _to_us_. https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_horizon https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_hor...
- qubex 6y agoAs I see it, there’s a vast cognitive chasm between the cosmic event horizon and the event horizon of a black hole, as the former preserves “continuity of locality” (my term) whereas the latter does not. Basically the the former is only an event horizon for us who are very distant from it, whereas the black hole’s horizon is an abrupt threshold in space. I don’t think it’s healthy to confuse the two.
- wnoise 6y agoThe locality is all equally continuous in all these cases. Someone near the black-hole horizon will see nothing unusual, and will not experience a horizon unless they are accelerating like mad to stay there. But someone doing that in flat space will see a horizon too -- see the Rindler coördinatization[1] of Minkowski space. It even has an analogous Rindler horizon, which seems to emit particles from the Unruh Effect[2]. I say seems to because particle number isn't invariant under acceleration. An outside observer will see a particle detector go off, but will interpret the accelerated detector as causing the particles, rather than the horizon. [1] https://en.wikipedia.org/wiki/Rindler_coordinates https://en.wikipedia.org/wiki/Rindler_coordinates [2] https://en.wikipedia.org/wiki/Unruh_effect https://en.wikipedia.org/wiki/Unruh_effect