Main Question or Discussion Point
Is there a temperature that black holes cease to emit non-zero mass particles.
The fermions emitted, of course, will follow a Fermi-Dirac distribution instead of Planck.I think you can still pretty much get away with using Planck's law, just interpreting hf as the mass-energy of the particle. I'm sure the statistical counting of polarization states is wrong, and the stuff relating to identical particles is wrong if the particles being emitted are fermions, but basically I think the shape of the high-energy tail of Planck's law just follows from the partition function.
http://en.wikipedia.org/wiki/Hawking_radiationAn important difference between the black hole radiation as computed by Hawking and thermal radiation emitted from a black body is that the latter is statistical in nature, and only its average satisfies what is known as Planck's law of black body radiation, while the former fits the data better.
While the answer seems clear, no, the details don't.Is there a temperature that black holes cease to emit non-zero mass particles.
Quoting Birrell & Davies,It would be interesting to estimate how much of an astrophysical black hole's mass is destined to be emitted as neutrinos, etc.
If it can, doesn't this thwart Penrose CCC which was just discussed in another thread. There, no one questioned the emission of radiation only from black holes at the end of this eon...no massive particles were claimed to be emitted.
Yes indeed! The book points out that the diameter of such a black hole would be about a fermi.A black hole hotter than 109K would seem really unusual....really small....
Is this saying as BH get smaller, hotter, they emit larger proportions of massive particles??
First of all I had not been aware if that is in fact accurate; if it is accurate, it was entirely missed in the Penrose CCC discussion by several forum experts and apparently by Penrose himself.So this is why the radiation from the hole is almost entirely massless until its last dying gasp.
I don't think he missed it. I think he just realized that it was an unimportant side issue.First of all I had not been aware if that is in fact accurate; if it is accurate, it was entirely missed in the Penrose CCC discussion by several forum experts and apparently by Penrose himself.
I listened to the entire Penrose lecture about his CCC theory at Perimeter online a few days ago and if he said anything about partile emission from BH at the end of the universe, when he appears to claim all is radiation, I'd be really surprised....
I cannot derive the conclusion that ALL massive particles must disappear. Nor can I tell how important it is that ALL do.The real problem with CCC is that he needs nonstandard particle physics to get all his massive particles to decay into photons.
One thing I don't recall being discussed in our threads is dark matter and the Higgs field. In his radio interview he says a requirement is that dark matter disappears and hypothesizes it reappears when the Higgs field does.....) As we approach the Big Bang,
moving back in time, we expect to find temperatures that
are increasingly great. And the greater the temperature,
the more irrelevant the rest masses of the particles
involved will become, so these particles are effectively
massless near the Big Bang.
I assume no Higgs, no 'matter'...thats a potentially slick way to eliminate mass....I don't see the relevance of the Higgs boson.
Sorry, but this verbal description is a little too vague for me. What would be optimal would be if you could find a published paper by Penrose, preferably one that's freely available on the web, that discusses what you're describing. Then we'd all see a clearly formulation expression of this. Did Penrose say something about the Higgs in the radio interview? It's just going to be way too hard to decode all of this based on a second-hand description of a verbal popularization. Have you tried, for example, searching on arxiv.org for Penrose's name, to see what is the most recent thing he's published on CCC? My impression is that the theory was rapidly changing ca. 2009-2010, and that ca. 2011-2012 it basically was found not to be viable, both because the nonstandard particle physics was incompatible with observation and because the claim of confirmation from the CMB turned out to be completely wrong.I assume no Higgs, no 'matter'...thats a potentially slick way to eliminate mass....
and Penrose mentions the Higgs field reappearing in the early universe.....he did not make clear when it 'disappeared' in his view.....
I'm wondering if the Higgs field can exist in a conformally geometric universe...if not, no mass!!