News for hackers. Stuff that matters.

A comment on 36B solar mass black hole at centre of the Cosmic Horseshoe gravitational lens. Parent comment

Re:36B solar mass black hole at centre of the Cosmic Horsesh... by mr_mitm on Monday August 11, 2025 @02:28PM (#44867673)
First of all, black holes have an interior and an exterior. Our universe only has an interior. Next, black holes have a singularity into which everything vanishes, or at least moves towards. Im our universe, everything moves away from a singularity. So if anything, it resembles a white hole more than a black hole. Also, our universe is expanding, whereas black holes shrink (unless matter falls into them, which can't happen to our universe because it has no exterior).

It really looks nothing like a black hole.

[ Parent | on HN ]
Re:36B solar mass black hole at centre of the Cosmic Horsesh... by tejtm on Monday August 11, 2025 @04:11PM (#44868895)
Agreed, how do you feel about our universe being some sort of post evaporated BH-like-thing from a previous universe-like-thing?
[ Parent | on HN ]
Re:36B solar mass black hole at centre of the Cosmic Horsesh... by pixl97 on Monday August 11, 2025 @04:52PM (#44869337)
>Next, black holes have a singularity into which everything vanishes, or at least moves towards

I mean, everything in our universe does move towards something. The future.

[ Parent | on HN ]
Re:36B solar mass black hole at centre of the Cosmic Horsesh... by MarkusQ on Wednesday August 13, 2025 @12:20PM (#44890459)
The interior and exterior are isolated; we have no idea if are universe has an exterior or not and, according to present theory, never will.

As another comment pointed out, in GR our "future" is a singularity which everything moves towards (so what we see as a time dimension).

"Expanding" and "contracting" depend on your coordinate system. If your rulers are shrinking, you can't tell this from space expanding.

The common factor here is you are wanting to use our reference frame (somewhere in this universe, not near a black hole) to describe things as they would be seen from other reference frames.

[ Parent | on HN ]