Comment on Black Holes
sem@lemmy.blahaj.zone 4 days agoAnd an infinitely dense point in spacetime doesn’t necessarily exist: it’s just what general relativity predicts is at the center of a black hole.
The last time our physical model of the universe predicted an infinite value, we ended up discovering new physics eventually (the ultrasound catastrophe).
And an infinitely dense point in spacetime doesn’t necessarily exist: it’s just what general relativity predicts is at the center of a black hole.
If the singularity at the center of a black hole didn’t exist, and was just extremely dense instead, would all of the other properties that we know is true about black holes be able to exist? For example we know that Sag A* and that one other black hole we ‘imaged’ give off no light, would that still be possible without a singularity?
In General Relativity, the way to get gravity so strong that not even light can escape is with a singularity: a point of infinite density. So, either this infinity physically exists, and maybe we’ll understand how better, or General Relativity may be incomplete: a model that works well most of the time, but doesn’t represent reality correctly at the extremes of heavy mass and small space.
Or at least that’s how I understand it. This has more info: …stackexchange.com/…/why-singularity-in-a-black-h…
This is similar to the ultraviolet catastrophe. Physicists predicted black body radiation using their current physical models, with high accuracy at low wavelengths of light, but at high wavelengths, the predictions diverged towards infinity, which disagreed with measurements.
Breakthroughs in quantum physics later reconciled theory with measurements.
One big difference with black holes is we cannot yet measure the actual density in the interior of the black hole. We just have the prediction that there is a point of infinite density.
I appreciate your detailed answer, thank you for taking the time :D
Ageroth@reddthat.com 4 days ago
I think you’re referring to the ultraVIOLET catastrophe
en.m.wikipedia.org/wiki/Ultraviolet_catastrophe
BussyGyatt@feddit.org 4 days ago
yeesh, what was the ultrasound catastrophe then?
sem@lemmy.blahaj.zone 4 days ago
This whole comment was a struggle to type on my phone at the time because the screen was wet, so at the end that one slipped though.
BussyGyatt@feddit.org 4 days ago
still, kind of funny wondering what an ultrasonic catastrophe might have been