On Thu, Nov 17, 2022 at 9:41 AM John Clark <[email protected]> wrote:
> On Wed, Nov 16, 2022 at 7:25 PM <[email protected]> wrote: > > >> *> Setting aside relativity for the nonce, the workability of >> transversable wormholes is getting more, >> better! https://journals.aps.org/prd/abstract/10.1103/PhysRevD.106.104024 >> <https://journals.aps.org/prd/abstract/10.1103/PhysRevD.106.104024>* > > > The trouble with the idea that a Black Hole is the mouth of a wormhole is > that the other end of the wormhole should be a White Hole and nobody has > ever detected one > That paper is about traversable wormholes held open by exotic matter, which probably could not form naturally (Kip Thorne talked in his paper about what might be possible for an 'advanced civilization'), but the traversable wormhole solution doesn't involve any event horizons, black hole or white hole. The idea of a black hole containing a wormhole comes from the eternal Schwarzschild black hole, but it's physically unrealistic because from the perspective of external observers this type of black hole would exist forever both in the past and future, whereas a physically realistic black hole would form from collapsing matter, from what I understand the GR solutions that have been found for dynamically formed black holes don't involve wormholes. The Schwarszschild black hole contains both a black hole interior region and a white hole interior region, though external observers would be able to see *both* particles emerging from the white hole region and particles falling in towards the black hole region, so from the outside it doesn't look specifically like a black hole or a white hole (and there are two distinct 'outside' regions, sometimes described as different 'universes' though they are all part of single connected spacetime). I think the diagram of the eternal Schwarzschild black hole in Kruskal-Szekeres coordinates is probably the most intuitive way to think about the weirdness of this solution since the diagram makes light cones look the same way they do in SR, there's a qualitative description of the diagram at https://en.wikipedia.org/wiki/Kruskal–Szekeres_coordinates#Qualitative_features_of_the_Kruskal–Szekeres_diagram -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAPCWU3KzZ2H1Hg2jLhbBA8r-jA-ckvA%3D78tq0bBChk0Ng8Y3Mw%40mail.gmail.com.
