How can something that doesn't really exist such as space and time possibly be warped? Physicists need to get a grip and understand that their model of the universe is completely wrong. There is no space or time and the universe has no shape.
The strange fate of a person falling into a black hole
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Re: The strange fate of a person falling into a black hole
#72And if you ever start to think Doctor Who is a wishy-washy-weeny, someone once pissed him off and he did this to them. Moral of the story: don't fuck with time lords.
Re: The strange fate of a person falling into a black hole
#73How can something that doesn't really exist such as space and time possibly be warped? Physicists need to get a grip and understand that their model of the universe is completely wrong. There is no space or time and the universe has no shape.
> How can something that doesn't really exist such as space and time possibly be warped?
Think of a surface of a ball: it locally looks flat, but globally is pretty warped. This is an example of a warped 2-dimensional space. The spacetime is just 4-dimensional analogue.
Re: The strange fate of a person falling into a black hole
#74I once saw a susskind lecture about the firewall problem where he explained that to check if someone falling into a black hole was incinerated, you'd have to fire so much energy at them, you'd end up incinerating them. Physics is weird. And, apparently, kinda passive aggressive. BONUS EDIT: here's a Greg Egan short story about transhumans diving into a black hole and trying to do physics on the way down: http://grege…
Is that the story in which there's a discussion about whether space-time is continous or discreet, the former case allowing infinite computation as you dive into, the latter not?
Re: The strange fate of a person falling into a black hole
#75[deleted]
Re: The strange fate of a person falling into a black hole
#76I once saw a susskind lecture about the firewall problem where he explained that to check if someone falling into a black hole was incinerated, you'd have to fire so much energy at them, you'd end up incinerating them. Physics is weird. And, apparently, kinda passive aggressive. BONUS EDIT: here's a Greg Egan short story about transhumans diving into a black hole and trying to do physics on the way down: http://grege…
Is that the story in which there's a discussion about whether space-time is continous or discreet, the former case allowing infinite computation as you dive into, the latter not?
I think I remember that coming up, amongst many other things.
Re: The strange fate of a person falling into a black hole
#77So I've had a question about stellar mass black holes that I can't seem to be able to get answered (the question was deleted for /r/askscience).
How does a stellar mass black hole actually form a singularity given the fact that there's gravitational time dilation? Wouldn't the heart of a black hole slow down relative to an outside observer as mass is added to it so that you never actually reach infinite density? It seems like you're fighting the upwards curve of a parabola to make that happen, and meanwhile you're releasing pressure from above via hawking radiation.
Re: The strange fate of a person falling into a black hole
#78Earlier quoted context omitted.
The theory very explicitly does not posit a "split in realities" or "parallel universes" or anything of the sort. It says there is quantum information both inside the black hole and outside it, and this is ok because they're supposedly causally disconnected from one another.
> The instant you entered the black hole, reality would split in two. From the 3rd paragraph. However, yes the alternate universe comes into existence when you reach the singularity. Still, if you can exist both inside and outside, then your ashes can exist in both places alongside living you without causing a paradox because you simply will not exist in the same space as you ashes that will arrive very much later an…
Reality only splits in two in the sense that the observer-dependent reality of the person falling into the black hole and the observer-dependent reality of the person remaining outside of it can no longer exchange information anywhere except inside of the black hole's event horizon.
The half of your light cone that extends into the future remains entirely within that event horizon. The outside observer's cone can remain outside of it only as long as she avoids crossing the event horizon.
Even if the outside observer decide to jump in just seconds after you, it is possible that the physics inside the event horizon would prevent her from ever catching up with you to compare notes, or even sending you a message. You could send a message with modulated x-rays, and she might pick them up with a VLF antenna. She might reply with a deep infrared laser and accidentally cook your brains with cosmic rays. Assuming a steep spacetime gradient as you approach the singularity, everything sent inward would be severely blueshifted, and everything sent outward severely redshifted.
There might even be a sort of Zeno's Paradox inside, where once you cross the event horizon, there's another event horizon beyond that, such that anything that much closer to the singularity than you are can never communicate with you, in the same way that you can never communicate with the universe outside the first event horizon.
Re: The strange fate of a person falling into a black hole
#79How can something that doesn't really exist such as space and time possibly be warped? Physicists need to get a grip and understand that their model of the universe is completely wrong. There is no space or time and the universe has no shape.
Do you have a line of reasoning for that?
Models which take spacetime to be able to be warped, /to my understanding/, make what are currently the predictions which are most matched by experiment.
I don't know why one would suppose that space and time do not exist, other than as some philosophical idea, but even if one does suppose that, it still appears to work well to model the universe as if they do exist.
One would not expect a Berkeleyan Idealist to complain on every article about nuclear fusion because they do not believe that atoms exist.
If space and time "do not exist", it seems like speaking of them as if they do would be a useful shorthand, in any case (Provided that they yield a useful model, which they seem to.).
Re: The strange fate of a person falling into a black hole
#80Earlier quoted context omitted.
Larger than the current life of the universe, not necessarily longer than the end of the universe, though that really depends on your model of how it'll all end. Some do involve black holes gradually boiling away to radiation being the last things being left.
Maybe there would be an eternity of black holes boiling / protons decaying. I doubt that since something ought to lose stability in the long run.
If spacetime continues to accelerate its expansion, a black hole at the future end of time might be like suddenly dropping the air pressure over a boiling pot of water--or maybe more like popping a blackhead pimple by stretching the skin on either side of it.
I am not a theoretical physicist, though, so whenever I think too hard about how that would actually work, I give myself a headache and need a good lie-down in a very dark room.