121–130 of 155 posts
The title is... odd. 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 b…
Should it be a big embarrassment for Phys. Rev. Lett., a big dip in their reputation? The whole point of respectable journals is that they filter out bad quality papers.
The title is... odd. 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 b…
> The title is... odd. Not if you know the reputation of John Baez: Anyone familiar with him or his writings would know without hesitation that he understands black-body and E&M radiation, so his choice of title is clearly meant to be provocative. It says to the reader "I wonder what he means?" To this reader, I'll also say that he delivered a terrific blog post.
This has become affectionately known as “click bait”.
No disrespect to the pedigree of the clearly distinguished author.
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.
lol, I wrote a very similar comment here a few days ago: https://news.ycombinator.com/item?id=43964524 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.
lol, I wrote a very similar comment here a few days ago: https://news.ycombinator.com/item?id=43964524 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.
Whether it’s nonsense or not, this quote in the critical assessment is concerning: > If I were a science journalist writing an article about a supposedly shocking development like this, I would email some experts and check to see if it’s for real. An attitude like that would have us all believing the earth is flat or that the sun revolves around the earth. After all, experts of the time believed both wrongly.
We shouldn't take the experts on blind faith, but we definitely shouldn't take the challenges on blind faith either.
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.…
Earlier quoted context omitted.
> The title is... odd. Not if you know the reputation of John Baez: Anyone familiar with him or his writings would know without hesitation that he understands black-body and E&M radiation, so his choice of title is clearly meant to be provocative. It says to the reader "I wonder what he means?" To this reader, I'll also say that he delivered a terrific blog post.
> It says to the reader "I wonder what he means?" This has become affectionately known as “click bait”. No disrespect to the pedigree of the clearly distinguished author.
Earlier quoted context omitted.
> Nothing to see in the sky, and you may well survive your visit to the event horizon. Then, dramatically less than one second later for any credibly sized black hole, you will meet the singularity, and IIRC you should probably expect to be squashed by tidal forces before that. Don't we know about a bunch of black holes best measured in AU? Won't you have a good chunk of time inside those? Does time dilation work sev…
I vaguely recall doing this calculation on a problem set. For a black hole roughly the size of the one at the center of our galaxy, IIRC you have well under a microsecond. I could be remembering wrong. Even worse: the way to maximize how long you have before you hit the singularity, you should do nothing. Firing your rocket in any direction gets you to the singularity in an even smaller amount of proper time: the sin…
You only get one microsecond as you cover over half a light minute? Huh.