Watsisname wrote:Source of the post As for looking into a white hole in a dimensionless universe, the concept makes no physical sense. A white hole can't exist in a dimensionless space. Nor can any observer, to make such an observation.
I would imagine it to be an anti-hyperbolic geometry that an asymptote, so that all outwards directions eventually converge at a finite radius, and the white hole being a topological feature which counters this geometry, like how a circle in hyperbolic geometry forms an infinite room, the white hole being a region that has dimensions, and the volume permits non converging directions, but then when you pass the threshold (event horizon), all directions now lead away from the white hole and further into the anti-hyperbolic asymptotic space where they all eventually "run out of dimensions" and arrive at the same 0 dimensional location a radius away from the white hole.
Watsisname wrote:Source of the post Under a transformation that reverses the direction of time in the Schwarzschild metric, things which would be falling into black holes will instead fall out of them.
Ah! So a double or just entropic time reversal. Either the sequence of events are reversed or both sequence and direction is reversed. Where the math gives the reversed result. k, that makes sense. Except... wouldn't anything coming out of a white hole experience extreme anti-time dilation? The moment it leaves, wouldn't it age to almost infinity? But also... I suppose that would would also be accelerated close to the speed of light... So that might actually counteract the anti-time dilation, time would pass slower and faster for you. Talk about gamma ray central XD
Watsisname wrote:Source of the post "Negative" matter would be a source of antigravity, and produce a white hole instead of a black hole if you could bring enough of it (and if such stuff exists) into a small enough region of space to form an event horizon. Same principle as forming a black hole, but with gravitational repulsion.
I can't imagine how one would obtain negative matter, as it would be like antimatter... but instead the entire universe is the wrong way around, and you'd need some tachyonic pair-production, how can someone even get a hold of imaginary light, or even a quantity of imaginary and anti-imaginary mass, and somehow reverse the direction of their products so that the negative matter formed is produced on the entropy forward side... Just imagine trying to even produce imaginary matter while standing on the real time axis, you'd need to somehow do something with imaginary time...I can barely comprehend what that would mean and do... It might just be easier to reverse entropy around an already existing black hole rather than attempt to make a white hole from scratch... Perhaps by somehow creating an alcubierre metric (already a problem) around a black hole, and well... turning it upside-down, if thats a thing? Or maybe the cheaty way; by creating a region of space with a very dense gas like Bose-Einstein condensate and create tiny pockets in it where their curvature is negative compared to the surrounding curvature, don't know if you'd be able to create a white hole with that...
Hmmm... would a white hole grow? I mean... would hawking radiation take place in reverse? Or would all those gamma rays coming out of a white hole make it shrink?