> As Mark Twain said, “A lie can travel around the world and back again while the truth is lacing up its boots.” Actually he probably didn’t say that—but everyone keeps saying he did, illustrating the point perfectly.<p>It was Gandalf who said that of course. And before you try to contradict me, let me point out that Gandalf is a wizard that has no need to bother with silly things like spacetime continuity.<p>P.S.: <a href="https://quoteinvestigator.com/2014/07/13/truth/" rel="nofollow">https://quoteinvestigator.com/2014/07/13/truth/</a><p>> In conclusion, there exists a family of expressions contrasting the dissemination of lies and truths, and these adages have been evolving for more than 300 years. Jonathan Swift can properly be credited with the statement he wrote in 1710 [(that does not mention footwear yet)].
Without a gravity well whose escape velocity exceeds c, how are they supposing hawking radiation happens in this scenario?<p>Both virtual particles-antiparticles survive (and promptly disappear because one didn't just cross an event horizon).
> 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.<p>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.<p>From Wikipedia [0], itself citing Daniel Harlow, a quantum gravity physicist at MIT:<p>> The conservation of baryon number is not consistent with the physics of black hole evaporation via Hawking radiation.<p>[0] <a href="https://en.m.wikipedia.org/wiki/Baryon_number" rel="nofollow">https://en.m.wikipedia.org/wiki/Baryon_number</a>
HN discussion at the time:<p>Universe expected to decay in 10⁷⁸ years, much sooner than previously thought (phys.org) <a href="https://news.ycombinator.com/item?id=43961226">https://news.ycombinator.com/item?id=43961226</a> 223 points, 5 days ago, 323 comments
lol, I wrote a very similar comment here a few days ago:<p><a href="https://news.ycombinator.com/item?id=43964524">https://news.ycombinator.com/item?id=43964524</a><p>It's true, that paper is nonsense. There's not really much else to say. Preprint servers sometimes publish the sort of stuff that wouldn't pass peer review. (Remember that S.Korean "superconductor" from about two years ago!?) The press should be cautious when writing about it.
Is there a simple way to understand why massive objects don't radiate gravitationally? Accelerating observers see a bath of thermal radiation via something called the Unruh effect. If you're standing on a planet, you're accelerating under gravity, and therefore don't you see Unruh radiation? Does this have any connection to Hawking radiation?
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.<p>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.
This detail caught my eye:<p>> [in their 1975 paper] Ashtekar and Magnon also assume that spacetime is globally hyperbolic<p>Isn’t the modern assumption that spacetime is globally flat?
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.<p>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.
Ok, we all understand the ancient problem and its current manifestation.<p>But what can be done? Science is not supposed to be the realm of disinformation, but it seems to have no real defenses. People are being paid to lie, no one is being paid to say they are liars, and from the outside scientific dispute looks a lot like politics, so scientists lose credibility by association.<p>That's a real problem.
This is partly why I roll my eyes when people who don't do research in a field start telling me about the "studies [they] found" while researching a topic. Unless you know the field and the research methods and have actually practiced them, reading studies is pointless, because you're too ignorant to evaluate them.
Anyone that predicts an event that far out in the future let alone 100 years out I would bet against any day of the week. This is couple trillion of trillions years using physics no way of proving
> As Mark Twain said, “A lie can travel around the world and back again while the truth is lacing up its boots.” Actually he probably didn’t say that—but everyone keeps saying he did, illustrating the point perfectly.<p>Well played.
The title is... odd.<p>White dwarfs and neutron stars are generally considered "dead stars", since they no longer have active fusion processes. But they do radiate from energy left over from the star's "death". (Mostly thermal energy for a white dwarf, for neutron stars there is also a lot in angular momentum and the spinning magnetic field.) In theory, they will eventually radiate all of their energy away and become black dwarfs or cold neutron stars, but IIRC, that would take longer than the current lifetime of the universe.
Should it be a big embarrassment for Phys. Rev. Lett., a big dip in their reputation?<p>The whole point of respectable journals is that they filter out bad quality papers.
Ah yes, our favorite HN “entertainment”. Scientists, quantum physicists in our case, having a beef about Hawking radiation :-)<p>Besides some high level ideas, which even us normal people can understand, there are so many details linked in the original post that you need an MSc/PhD to fully understand them.<p>For the time being, let’s just keep that the universe has a few extra trillion years, and isn’t expected to decay in 10⁷⁸ years ;-)
I couldn't really make heads or tails of this but if they aren't are emitting are they absorbing instead?<p>I feel like the only way not to emit is to absorb.