IIRC, isn’t it closer to a white hole, what with expansion? If you were far enough away, you cannot reach ‘there’ vs being guaranteed to reach ‘there’ like a black hole. Though really, it’s neither. Just curved spacetime.
The fact we think of white holes and black holes as separate entities just goes to show our great lack of understanding of spacetime.
I mean, Schwarzschild radius shows that for a medium of constant density (and on a large scale, Universe is fairly uniform) there is an upper limit of a radius of a ball comprised of said medium above which it will form an event horizon.
Which means that an infinite universe of non-zero density is either a bloody paradox (spend a minute deciding where exactly event horizons should form and whether there will be gaps), or our understanding of gravity and spacetime breaks on ginormous scales just as it does on micro ones.
PS: I have seen no physicists talk about this, so there’s a good chance that there’s a simple resolution to the problem and I’m just stupid.
Or that the observable universe could be inside of a black hole. Don’t watch too many black hole videos before bed.
Planet 9 is not a primordial black hole and it can’t hurt you. 🙀
IIRC, isn’t it closer to a white hole, what with expansion? If you were far enough away, you cannot reach ‘there’ vs being guaranteed to reach ‘there’ like a black hole. Though really, it’s neither. Just curved spacetime.
The fact we think of white holes and black holes as separate entities just goes to show our great lack of understanding of spacetime.
My understanding is its similar in difference to a protostar and a nova
I mean, Schwarzschild radius shows that for a medium of constant density (and on a large scale, Universe is fairly uniform) there is an upper limit of a radius of a ball comprised of said medium above which it will form an event horizon.
https://en.wikipedia.org/wiki/Schwarzschild_radius#Calculating_the_maximum_volume_and_radius_possible_given_a_density_before_a_black_hole_forms
Which means that an infinite universe of non-zero density is either a bloody paradox (spend a minute deciding where exactly event horizons should form and whether there will be gaps), or our understanding of gravity and spacetime breaks on ginormous scales just as it does on micro ones.
PS: I have seen no physicists talk about this, so there’s a good chance that there’s a simple resolution to the problem and I’m just stupid.