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Black hole singularity is a surface not a point

214 pointsby raattgiftyesterday at 5:02 PM152 commentsview on HN

Comments

sigmoid10yesterday at 5:20 PM

Should be pointed out that this is a critique of common popsci journalism tropes and not a fancy new research result. Anyone who has taken a graduate level class in General Relativity would have been able to tell you the same.

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Certhasyesterday at 5:22 PM

As is nicely visualised by it's Penrose Diagram, e.g.

https://jila.colorado.edu/~ajsh/insidebh/penrose_schw.gif

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kazinatoryesterday at 9:18 PM

> Black hole singularity is a surface not a point

Might they be trying to say this?

1. The boundary of the black hole which traps light, etc, is called the event horizon, and sits at the Schwarzschild radius. This is a geometric surface.

2. There is no singularity at this surface.

3. In models of black holes, there is a gravitational singularity at a point in the centre: https://en.wikipedia.org/wiki/Gravitational_singularity which is a topic with nuances.

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sfinkyesterday at 7:27 PM

Off-topic, but it makes me think of "reasoning black holes": you get enough like-minded people together that they start reinforcing each other's logic and beliefs until not only those people get completely detached from reality, but anyone who interacts with them gets sucked in as well unless their own logic ("velocity") is adequate to skirt the edge and escape, forever altered by the experience.

Similar questions arise: how would you know if you were inside one? The laws of logic ("physics") seemingly don't apply, but there's no way to test them in that environment.

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lukeifyyesterday at 9:19 PM

I know this isn't a new discovery but I fully expect the next major theoretical physics breakthrough to be discovered by a frontier LLM at this point, given their aptitude at solving a lot of the recent mathematical conjectures.

dj_axlyesterday at 8:31 PM

scoffs Well yeah everyone and their aunt knows singularities have 5 dimensions.

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dekdropyesterday at 5:47 PM

How does one descr blackhole to a non-physicist without losing much accuracy? I just it of a very-dense-object.

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imzadiyesterday at 6:24 PM

Would this apply also to the singularity at the beginning of the universe? I guess I thought that the singularity was where all matter is compressed so much that it occupies a zero dimension point. I'm not sure if that applies equally to black holes and the singularity at the beginning of the universe. I'm kind of dumb on this stuff even though it fascinates me.

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yubblegumyesterday at 7:35 PM

Is there such a thing as a "point" in the universe?

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ck2yesterday at 5:27 PM

what's really going to blow your mind is

while you probably assumed or knew spinning black holes move space around them

spinning black holes also move TIME around them

* https://www.science.org/doi/10.1126/sciadv.ady9068

so in theory a spinning black hole that's been around for billions of years has a time drag around it in a path that is billions of years old

(no we can't navigate it because yes that would be time travel to the past and violates causality)

black holes are just so weird with every new detail even more weird

oddly more interesting to me to try to grasp neutron stars (densest objects before black holes and are still visible, our entire solar system in a neutron star would be only 10km 6.2miles across)

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throwawayffffasyesterday at 9:57 PM

Or you know there is no such thing as a singularity, and stars collapse to fuzzballs[1]

https://en.wikipedia.org/wiki/Fuzzball_(string_theory)

chendawenplustoday at 1:42 AM

is hole

metalmanyesterday at 9:15 PM

treating a black hole as a point, or ;) pointicle,may be valid as matter may be condensed, to the, I mean ,in such a way that there is NO space left whatsoever, and therefor no room for physical dimensions to exist in, and the entire body functions as an undiferentiated body of stuff, or giant pointicle that destroys time and space. Hopefully very soon we will get news about our galaxys central black holes interaction with a star that is orbiting very close but at 8% light speed, which may reveal if our blackhole is spinning, and if that is the case the we would have proof of energy/information/gravity waves? escaping from a black hole, along with gravity which while apparently imune to its self, nothing else is so far.

542458yesterday at 5:39 PM

[dead]

helfyesterday at 5:30 PM

[dead]

Yiinyesterday at 6:41 PM

[flagged]

dborehamyesterday at 6:16 PM

Isn't that how we're inside one.

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Groxxyesterday at 6:13 PM

Well... yeah? That's describing the event horizon. It's a term roughly as widely used as "singularity".

Talking about the inside of a black hole is indeed rather pop-misunderstood though, yes. But it's not like physicists are especially confident about the details either. Theoretical astrophysics changes a lot as time goes on and our instruments improve, and it's a rather hard field to do experiments on to get better data quicker.

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Eridanus2yesterday at 5:24 PM

Contains 08 rendered frames of a free falling observer's view while crossing the event horizon. This is not reddit, but plz someone animate it :}

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jamesforestwestyesterday at 5:31 PM

Interesting work. The idea that the singularity is a surface rather than a point was unexpected to me even though it seems to follow logically from the theory of relativity. I wonder how this reconciles with quantum gravity. If the singularity is truly a two-dimensional surface, perhaps it's related to Hawking radiation and the thermodynamics of black holes?