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Uh, this is why I tried to study pure maths (it's less physics and more weird differential geometry) I can recommend this paper [0] that talks about simulations
by namibj 8y ago
Uh, this is why I tried to study pure maths (it's less physics and more weird differential geometry)
I can recommend this paper [0] that talks about simulations that show a black hole just implodes in a weird way and kind of does not stop imploding, due to space-time getting stretched with a speed above that of light, as measured within a frozen moment in time, and summed over some line from inside to outside. A working analogy could be a 2d-spacetime, represented in 3d-space as a soap bubble film. Imagine the traditional visual funnel shape the space time around a black hole is often depicted as, compared to the downwards bump normal stars/planets are depicted.
So, now, the thing is that the effect of gravity, e.g. gravitational waves, are bound by the speed of light. They can not escape a black hole.
In the soap example the gravity waves would be film thickness waves, e.g. longitudinal waves in the thin soap sheet.
Those are bound by the speed of sound in their medium.
Imagine a stream of air with significantly higher speed than the sound in the soap, getting blown downwards this funnel. Also imagine the funnnel still having a closed tip made from soap at the start.
Thing is, this air will hit the tip, propell it downards, and suck the part close to the center down just by itself, without the center indirectly pulling on it.
Due to the supersonic nature, the ripple created from the initial impact of air onto the center will _never_ get out of there, just because the medium the waves travel through, when measured over the distance from where the wave is right now, to where the outside world with neglegible space-time (or soap-film) curvature is, expands faster than the wave travels. This does not mean the wave does not travel at all, just that once the distance you want it to travel increases enough, the propagation medium's expansion results in weird effects.
If someone is willing/able to point me to some research or possibly even wants to use existing skills with the related differential geometry maths, I'd really like that.
Edit: I might add that anything that falls into the black hole will, even in it's own reference frame, _never_ reach the center, and the only reference frame that possibly sees a steady state field curvature in finite local time could be the center of the collapse.
[0]: https://arxiv.org/abs/1402.1524 https://arxiv.org/abs/1402.1524 (Which was published about half a year after I initially and timestamped communicated the idea to a physics teacher who was willing to explain me the differential maths used in Einstein's field equations.)
- JadeNB 8y ago> https://arxiv.org/abs/1402.1524 https://arxiv.org/abs/1402.1524 (Which was published about half a year after I initially and timestamped communicated the idea to a physics teacher who was willing to explain me the differential maths used in Einstein's field equations.) Maybe I'm misunderstanding your point, but your parenthesis seems to suggest that you would like to claim some credit for the idea. If not, then you can just ignore what I'm about to say. If so, then your comment seems to suggest that you came up with the idea, but weren't sure about the mathematics of it. In modern physics of this type, where experimentation is not practical, the math is the physics; that is, I think the problem is not so much coming up with ideas—my impression is that there are hypotheses and to spare—but rather being able to back up those ideas with rigorous calculations.
- monocasa 8y ago> In modern physics of this type, where experimentation is not practical, the math is the physics I think Feynmann would disagree with you. http://www.youtube.com/watch?v=obCjODeoLVw http://www.youtube.com/watch?v=obCjODeoLVw
- mlevental 8y agofeynman died 30 years ago. it's plausible the culture of the field has changed (nm that feynman wasn't the arbiter of culture to begin with)
- JadeNB 8y ago> it's plausible the culture of the field has changed (nm that feynman wasn't the arbiter of culture to begin with) To be fair to monocasa's objection (https://news.ycombinator.com/item?id=17101892 https://news.ycombinator.com/item?id=17101892), the rebuttal was not of a claim that the culture of physics was mathematical but literally of my claim that (certain) physics was mathematics.
- jschwartzi 8y agoI'm not sure that's the case. He's not saying that the mathematics doesn't represent the physics. He's saying that in order to apply the mathematics we have to have some empirical model to which the axioms of the mathematical system applies. As long as that's the case, the mathematics can provide insight into the physical system. But where the mathematical tools break down are in the areas where we don't have any data. From a physical perspective the math, in this case, is moot. We have no data about what happens past the event horizon, so I could just as easily say that it encompasses a space filled with tiny pink unicorns which exhale confetti and it would be just as meaningful. What we know is that something different happens. So there's really no room for either the mathematicians or the physicists to speak with authority on what happens. What we're left with is very well-informed speculation about a really interesting region of space-time.