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Dead Stars Don’t Radiate

johncarlosbaez.wordpress.com

11–20 of 155 posts

Re: Dead Stars Don’t Radiate

#11
post #10
post #4

There's an issue this highlights and it's not that the original authors were stupid so much as there's clearly a lot of knowledge held in silos. That's not a good thing if your goal is to advance everyone's knowledge. Whatever is going on in academia is failing relatively closely related fields which is not good.

Well, there's another aspect which is that the original authors and pop-sci journalists don't seem to be able to understand where they went wrong or how outrageous their claims are, precisely because their jobs depend on not understanding. The could have corrected it. We could not still be circling this drain 2 years later, but we are. Kinda classic. Kinda boring.

It helps that this is a genuinely difficult process to understand and requires an enormous fluency with QFT. Most people who fit that bill have better things to do with their time than write popular science articles or correct them.

Re: Dead Stars Don’t Radiate

#12
post #4

There's an issue this highlights and it's not that the original authors were stupid so much as there's clearly a lot of knowledge held in silos. That's not a good thing if your goal is to advance everyone's knowledge. Whatever is going on in academia is failing relatively closely related fields which is not good.

99.999999999% of people do not have enough knowledge to even dream of beginning to understand a majority of research. Adults can barely read, much less be able to pass Calc 1.

Re: Dead Stars Don’t Radiate

#13
> It would also mean that quantum field theory in curved spacetime can only be consistent if baryon number fails to be conserved! This would be utterly shocking.

Is it really shocking (today)? I mean, isn't this a logical consequence of Hawking radiation for black holes? I thought we were shocked by this a long time ago, but now we're ok with it. The authors of the paper in question may very well be wrong in their calculations (I can't say), but this blog post doesn't smell good to me because of doubtful statements like these, passed off as so obviously true that you must be an idiot not to agree. That kind of emotional writing does not become someone whose profession should focus on scientific persuasion.

From Wikipedia [0], itself citing Daniel Harlow, a quantum gravity physicist at MIT:

> The conservation of baryon number is not consistent with the physics of black hole evaporation via Hawking radiation.

[0] https://en.m.wikipedia.org/wiki/Baryon_number

Re: Dead Stars Don’t Radiate

#14
post #4

There's an issue this highlights and it's not that the original authors were stupid so much as there's clearly a lot of knowledge held in silos. That's not a good thing if your goal is to advance everyone's knowledge. Whatever is going on in academia is failing relatively closely related fields which is not good.

It certainly wasn't in "silos", it's all on arxiv!

But yes: the world is complicated and it's easy to make mistakes outside your core field. The point of the scientific process is to get things in front of eyeballs who can spot the mistakes, c.f. the linked blog post. Then everyone fights about it or points and laughs or whatever, and the world moves on. The system worked.

What the process is not good at is filtering new ideas before people turn them into news headlines. And sure, that sucks. But it's not a problem with "academia failing", at all. The eyeballs worked!

Re: Dead Stars Don’t Radiate

#16
In black holes we have essentially a "loss of a dimension" (it's a much bigger story to explain what that even means, that I won't attempt here), so it might be the case that the three-quark arrangement known as 'baryons' only forms according to number of space dimensions (3D == 3 Quarks), making baryons only happen in 3D, so that when stuff reaches an event horizon, the quarks rip apart and rearrange into something where there's simply no such thing as a baryon (i.e. in 2D space). I'm someone who thinks the 'surface' of an event horizon is where the laws are preserved, and that the singularity or even perhaps the entire interior inside black holes may simply not exist at all.

Much of where Relativity "breaks" spacetime (i.e. problems with infinities and divide-by-zero) can be solved by looking at things as a loss of a dimension. For example, length contraction is compressing out a dimension (at light speed), and also time dilation (at event horizons, or light speed) is a removal of a dimension as well. Yes, this is similar to Holographic Principle, if you're noticing that. In my view even Lorentz equation itself is an expression of how you can smoothly transform an N-Dimensional space down to an (N-1)-Dimensional space, which happens on an exponential-like curve where the asymptote is reached right when the dimension is "lost". I think "time" always seems like a special dimension, no matter what dimensionality you're in, because it's the 'next one up' or 'next one down' in this hierarchy of dimensionality in spaces. This is the exact reason 'time' in the Minkowski Space distance formula must be assigned the opposite sign (+/-) from the other dimensions, and holds true regardless of whether you assume time to be positive v.s. negative (i.e. called Metric Signature). This of course implies our entire 4D universe is itself a space embedded in a larger space, and technically it's also an "event horizon" from the perspective of higher dimensions.

Re: Dead Stars Don’t Radiate

#17

https://archive.is/mG1KS

As best I can tell there's no paywall on TFA, so I really don't think there's any reason to go through archive.is, which adds its own advertisements (if you don't block them).

archiving isn't just to circumvent a paywall. There's also the HN hug of death, possible geoblocks or an actual interest in archiving the article as it was written at the time these comments.

Re: Dead Stars Don’t Radiate

#18
post #4

There's an issue this highlights and it's not that the original authors were stupid so much as there's clearly a lot of knowledge held in silos. That's not a good thing if your goal is to advance everyone's knowledge. Whatever is going on in academia is failing relatively closely related fields which is not good.

> There's an issue this highlights [...] there's clearly a lot of knowledge held in silos.

I think the real issue this highlights -- which is something everyone knows and still everyone does -- is that people love to spread and discuss sensational stories, and no one likes to hear naysayers ruining the fun.

Look the discussion of the original story here in HN[1]. There's a comment by A_D_E_P_T way down in the discussion explaining why the paper is nonsense and pointing to one of the replies objecting to it mentioned in the article from this post. That comment was downvoted by HN readers. I know because it was greyed out when I upvoted it days ago.

So there's no knowledge silo -- us simple folk just want to discuss the newest breakthrough without looking too hard, because that spoils the fun.

[1] https://news.ycombinator.com/item?id=43961226

Re: Dead Stars Don’t Radiate

#19
post #8
post #5

Without a gravity well whose escape velocity exceeds c, how are they supposing hawking radiation happens in this scenario? Both virtual particles-antiparticles survive (and promptly disappear because one didn't just cross an event horizon).

You have to remember the "one particle in the pair fails to escape the event horizon" explanation is a simplification of the alleged reality, which is the scattering of particles (or fields) in the presence of an event horizon. As far as I know there is no intuitive, non-mathematical way to describe this accurately, so science communicators of all stripes tend to approximate it in ways that can mislead the audience.…

Thanks! I just learned something!
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