'Wobbling black hole' most extreme example ever detected | Hacker News Reader

'Wobbling black hole' most extreme example ever detected

phys.org

56 pointswglb21 comments

A bit off topic, but I wonder how do researchers keep track of these discoveries. There are so many stars, galaxies, objects, that in 20 years from now there are billions of studies done on maybe just a few of them. How do you know not someone else already did extensive research on the object you study?

There's a website called Simbad that keeps track of measurements and any publications that reference astronomical objects: http://simbad.u-strasbg.fr/simbad/

Edit: For example, here is a list of articles that reference this event: http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=GW200129_0...

(Currently only two papers are indexed.)

It is hard. In a nearby field, I once spent a few months characterizing a high-precision mechanical high-vacuum pressure sensor, astounded that nobody else had done similar work many decades prior.

Turns out I was missing a critical keyword from the early 1900s. All of the researchers in the field from ~1900-1940 used the term "manometer" to refer to even precision vacuum gauges. Once I had it, it unlocked a flood of references to top-notch work.

The real key is a living corpus of scientific knowledge -- people you can ask and solid review papers. It is one of the superpowers of the very-experienced and the well-read to be able to know what has already been done.

If something matters, it will generally get rediscovered in fairly short order. The biggest risk comes with measurements made that either can never be repeated (think changing bio-ethics rules or SN1987A) or can only be repeated at great cost (people are still analyzing high-energy physics experiments from the 1990s and earlier).

There's a delightful insight here that I've seen in several different fields, which is not commonly taught in school: when trying to research a thing, first find out what other people have called that thing.

When we were researching the possibility of having cell towers on solar planes or blimps, we had trouble locating other efforts to explore the same until we stumbled across the verbiage "High Altitude Platform Systems (HAPS)" and unlocked a wide body of research and people that had investigated exactly this.

My best technique so far for doing this is to search in Google scholar for the plain English description of what I'm looking for, and then to go through the papers found to see the language and keywords used there. If I do another search with that keyword, do I find other papers talking about the same thing I'm talking about?

There are only three detectors available (two LIGOs and VIRGO), and the strongest signal unfortunately also had an overlapping glitch, so there are still some data reduction issues that make interpretation difficult: https://arxiv.org/pdf/2206.11932.pdf

It's the same way with particule physics there are still a lot of unknowns. We have alot of theories but we don't know enough to really explain all we see. Think how far we have came in particule physics. First they though protons and neutrons we're the smallest. Then they said the same thing about quarks then discovered other particules that made up quarks. Personally I like that ever time society this is they have figured the world or universe out we find we are just starting. That mystery amazes me. I did some study on black holes and while we know some aspects of the behavior they display we don't know it all yet.

The referenced article suggested there's an upper limit to the spin rate of a black hole. From the penultimate paragraph: "The larger black hole in this binary, which was about 40 times more massive than the Sun, was spinning almost as fast as physically possible."

I don't get what limits black hole spin rate. As I understand it, The hole isn't a material surface, nor is there mass within, except for what's caused the singularity. Which might or might not be larger than a point.

Can anybody clue me in as to whether there's an upper spin rate limit, and if so, why? Thanks.

This PBS Space Time video does a good job of explaining it https://youtu.be/1Z5fnwUmTSY. tl;dr the inner and outer event horizons of spinning black hole cancel out leaving a naked (ring) singularity which is believed to be prevented by the “Cosmic Censorship Hypothesis”. In the math it causes the event horizon radius to become complex which is believed to be “unphysical”. However maybe not, many “unphysical” mathematical objects have later turned out to be real such as black holes themselves (Einstein thought they were just a mathematical artefact) and anti matter (a result of negative roots of the Dirac Equation). Complex numbers are also an intrinsic part of the way Quantum Mechanics works, so perhaps there are naked singularities.

Correct me if I’m wrong, but the Schrödinger equation isn’t the only mathematical treatment of the stochastic nature of quantum phenomena.

I thought matrix mechanics was with real numbers and was mathematically equivalent. I also thought there were different statistical systems that included “negative” probabilities that can be used to describe wave packets without needing complex numbers.

I do agree that sometimes the maths leads you to a truth in reality. Though sometimes it doesn’t.

I’m not too familiar with QFT, does that require complex numbers?

What do you mean by “require”? Complex numbers can be represented as a 2x2 matrix of real numbers (a scaled rotation around the origin), so transitively, that’s true for any equation involving complex numbers.

I don’t remember exactly since it’s been a while since I read it, but in Scott Aaronson’s Book “Quantum Computing Since Democritus” which is about how physics informs what’s computable. He talks about how the behaviour of quantum mechanics follows fairly straightforwardly from considering how probability works with complex numbers / bloch spheres. You can’t properly reproduce Bell’s Inequality without them I think?

Thanks for this. The subject is way out of my wheelhouse, but I enjoy clinging to the coattails of explorers of worlds I don't understand.

> The hole isn't a material surface, nor is there mass within

Are you saying a black hole is considered to have no mass at all? That it is literally considered a hole?

Where would matter "go" when it falls in? Would it be emitted in its entirety (and no loss) as Hawking radiation?

I thought the enormous gravity defines it to be a black hole where not even light can escape, but there is still "matter".

This article was rather light on details and didn't explain things very well. They don't tell how much the precession was, how it was detected, nor much else about it.

The Nature paper says that the precession rate was about 3 Hz. In other words, the periapsis would circle around about 3 times per second.

For comparison, the system with the next fastest precession is a binary pulsar system that has a precession rate of ~10^-10 Hz. So this is 10 orders of magnitude faster.

This was determined by analyzing the gravitational radiation waveform from the merger. Properties of the system like the masses, spins, and their orientations all leave unique signatures in the gravitational radiation waveform.

You can take a look at the original paper here (it's not very long): https://www.nature.com/articles/s41586-022-05212-z

The paper on which the article was based. https://arxiv.org/abs/2112.11300

When they say wobble, by how much distance does the space aroubd it wobble? How would this feel on earth?

Now this I'm curious about.

Is this the same effect as seen in the precession of Mercury's perihelion?

From what I can gather, it's a much stronger example of the same general phenomenon, yes.

Explanation: https://aether.lbl.gov/www/classes/p10/gr/Precessionperiheli...

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