Naked Science Forum
On the Lighter Side => New Theories => Topic started by: samcottle on 19/06/2022 08:35:29
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Hi there, I recently drafted this article/paper on some recent work in cosmology on dark energy. I was wondering if anyone here would be good enough to provide some feedback. Best wishes, Sam Cottle.
‘Dark’ Energy is Probably Radiation Pressure, But That's Not The Whole Story.
Samuel P. Cottle,
Unaffiliated.
Abstract.
Experiments in the trapping and cooling of atoms using laser light, as well as observed phenomena due to radiation pressure, give a high likelihood for explaining the effects of so-called dark energy. Visible light, as well as photons from every other part of the electromagnetic spectrum would have been building up between galaxy clusters since their formation. The intervening 13.5 billion years or so would have seen vast numbers of photons amassed in the recesses of intergalactic space unable to escape to more distant reaches of the universe due to the reflective capacity of the intervening material. In this paper, I draw the conclusion that, while this is sufficient to explain the expansion of the universe, a deeper understanding of the Hawking radiation emitted from galaxy clusters (and its attendant contribution to the cosmological constant) is needed to fully elucidate the mode by which that expansion accelerates.
Atom trapping and manipulation at cosmic scales.
Given our knowledge [1] of how atoms may be trapped and manipulated using lasers in an experimental setting, and given that we are, of course, aware that galaxy clusters are formed of atoms, we may infer that radiation pressure makes a significant contribution to dark energy. Zhang and Wang (2021) [2] draw a similar conclusion, as did an independent researcher by the name of Wangchung Hu (2009) on the ‘Naked Scientists’ online forum [3]. The discrepancy in the results derived by Zhang, Wang and Hu with observation consists in the fact that we’re aware that the universe’s rate of expansion is not constant but accelerating [4]. If all the radiation pressure caused by this buildup of photons between galaxy clusters since the beginning of the universe were the only cause of expansion, we could anticipate that the rate of expansion would be roughly constant.
As it is, we’re aware of acceleration in the expansion of the universe. We must, therefore, add in additional variables to account for this acceleration; this would provide us with an accurate means of modelling the universe’s continued expansion. Hawking [5] famously noted that black holes emit radiation and, ultimately, evaporate. The conjecture I would add into this debate is that this effect is not limited to black holes. I would propose that all matter gives off Hawking radiation (in the form of photons) and would (in theory) eventually evaporate; evidence for this might be provided from observations of the Casimir effect [6], particularly any experiments aimed at gauging variations in the Casimir effect due to the presence of smaller or larger masses. And, if we thereby find that certain masses give off greater levels of Hawking radiation (in addition to whatever light they naturally reflect and/or emit) we may have isolated one of the additional parameters necessary in accounting for this acceleration.
Additionally, this notion of radiation pressure giving rise to cosmic expansion follows somewhat naturally from an idea I put forward (in rougher forms, online) back in 2016. Working on quantum gravity, I’d proposed that gravitational fields are formed of electron densities. Given the fact that electrons reflect photons [7], we’re thereby put in a position wherein we can reasonably assert that galaxy clusters must be reflecting large quantities of radiation. Following from this, we can infer that the recesses between these clusters, whose expansion we observe accelerating, therefore represent buildups of trapped radiation. The cosmological constant of galaxy clusters; if we’re invoking notions of regional variation in the value of the cosmological constant (if it were, so to speak, a cosmological variable); may be attributable to the electrons forming the gravitational field(s) of said clusters transporting photons to the recesses outside those clusters at varying rates due to differences in the varying, relative density of background electrons at different regions of space.
Likewise, the Hawking radiation of black holes (and any other massive object composed of atomic, or hadronic material) would be explained as a consequence of these gravitational electrons tunnelling to regions within the event horizon of a black hole, absorbing a photon there, then tunnelling outside the event horizon to deposit the photon in space. A partial consequence for this model of accelerating expansion is that it would need to incorporate considerations given to the reuptake of photons by these background (‘gravitational’) electrons. How this would vary in different regions of space, and the impact of these variations on the universe’s likelihood to expand in different regions, are further considerations within the proposed model. Hence, a consequence of this might be that, since the reuptake of a photon is less likely in a region with fewer background electrons, the fact of the universe’s expansion in and of itself is liable to cause its expansion to accelerate. This is because, if there are fewer electrons in a given region; such as between galaxy clusters; there is a lower probability that another background electron will absorb the emitted photon; or, it will take longer for a given photon to be absorbed once more by the background due to the larger spaces between background electrons.
Conclusion.
I broadly agree with the conclusions of Wang, Zhang and Hu insofar as radiation pressure is very likely a significant component of what we refer to as dark energy. Finessing this idea a little further, I’d have said that a degree of Hawking radiation (and/or Casimir force) generated by the background is necessary, in addition to considerations given to the background's liability for photon reuptake, in accounting for the universe’s accelerating expansion. The implications of this notion for our study of cosmological evolution would be profound if taken seriously in the community of cosmologists since, if the universe were to, at some point, lack a significant source of radiation to contribute to these buildups, we might anticipate its collapse at some future point due to gravity.
References.
[1] Phillips, W.D. (1998), Laser Cooling and Trapping of Neutral Atoms, Reviews of Modern Physics, Vol. 70, №3,
[2] G Zhang and X Wang (2021) J. Phys.: Conf. Ser. 2014 012010
[3] Wangchung Hu (2009), Is radiation pressure a significant factor in dark energy? https://www.thenakedscientists.com/forum/index.php?topic=22658.0#:~:text=Radiation%20pressure%20P%20is%20in,can%20perfectly%20fulfill%20our%20observation., Accessed: 16/06/2022,
[4] Rubin, D. and Hayden, B. (2016) Is the universe’s expansion accelerating? All signs point to yes, https://arxiv.org/abs/1610.08972, Accessed: 16/06/2022,
[5] Page, D.N. (2004), Hawking radiation and black hole thermodynamics, https://arxiv.org/pdf/hep-th/0409024.pdf, Accessed: 16/06/2022,
[6] Nguyen, T.T., (2003), Casimir Effect and vacuum fluctuations, http://www.hep.caltech.edu/~phys199/lectures/lect5_6_cas.pdf , Accessed: 16/06/2022,
[7] Bartell, L.S., (1967), Reflection of electrons by standing light waves, https://aip.scitation.org/doi/10.1063/1.1709723, Accessed: 16/06/2022,
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Hawking radiation emitted from galaxy clusters
Galaxies emit all the normal forms of radiation: light, radio waves, UV, X-Rays, cosmic rays, gravitational waves, neutrinos, etc.
- What is unique about (hypothetical) Hawking radiation is that it is emitted by black holes, which emit none of the above forms of radiation
- It is true that a galaxy also contains some black holes, but I guess that a single red dwarf star would emit more radiation than Hawking radiation from all the black holes in a galaxy (without doing the calculation!).
photons amassed in the recesses of intergalactic space ... due to the reflective capacity of the intervening material
We do see some galaxies at very high red shift, and the James Webb Space Telescope should reveal many more.
- Photons from these galaxies did reach us, without being reflected away by the intergalactic medium, which is extremely tenuous.
- If the intergalactic medium were reflective, we would see a reflection of our own galaxy, much brighter than we see these distant galaxies.
radiation pressure caused by this buildup of photons between galaxy clusters
Radiation pressure is a real thing - there have even been some experiments using radiation pressure to change the orbit of a satellite in Earth orbit.
But radiation pressure occurs when photons are reflected from a mirror surface, or absorbed by a non-mirror surface (the latter provides only half of the momentum).
However, if these photons are still in intergalactic space, they have not struck anything in our galaxy, and have imparted any momentum to our galaxy.
At this point, I gave up and moved this topic to "New Theories".
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If Hawking radiation were to be anything, it would almost certainly be gamma-ray photons. In spite of any new physics in this proposition, the gravitational effects near black hole event horizons would shift photons to such an extreme on the blue end of the EM spectrum that they would be among the highest energy realm of gamma rays. When there is less gravitational influence on photons, they become red-shifted and lose energy rather than gaining it.
I fail to see why there should be something special about black holes, or why a black hole would emit a special form of radiation that wouldn't also be emitted by a pulsar, neutron star, red dwarf, or, for that matter, any other celestial body. If physics remains consistent between these more familiar bodies (which, to a reasonable extent, it does) why would we need to invoke any special weirdness so far as black holes are concerned? I am (admittedly) less concerned with what we characterise in an acute sense as 'Haking radiation' (i.e. supposed special radiation from black holes) and with the broader implications of Hawking's thesis on this matter. Given a background of photon-emitting particles, i.e. probably electrons (which, for various reasons, I suspect is highly probable), then we have an explanation of the Casimir force and the so-called 'vacuum energy' of the universe. Gravitational fields construed as electron densities also neatly provide a reflective capacity for galaxy clusters which can then be used to explain 'dark' energy through invoking a notion of radiation pressure. Sure, a fair bit of distant light would be getting through to us; the fact that all the light from distant galaxies clearly isn't reaching us is a smoking gun for the idea of some absorbent medium lying in the intervening reaches of space. I also don't think we'd see a reflection of our galaxy. By the time the light emitted from our galaxy has reflected off the medium, we'd have moved to a different point in our orbit around the centre of the Local Group. If we were in Andromeda, we would be seeing the Milky Way at some point in the past; undoubtedly this must, in its turn be reflected, or transported, via some medium; 'spacetime', or otherwise (otherwise it'd reach us instantaneously).
It would, of course, not be a 'mirror surface' reflecting these photons, however, as you rightly point out, a 'non-mirror' surface would impart 'half the momentum'. My suggestion is that this trapped radiation between galaxies (or galaxy clusters) is being reflected by the tunneling electrons forming their gravitational fields; if there were no such clouds of electrons then the photons would be reflected by electrons regardless since the light bouncing off any object is reflected by the electrons in the atoms comprising that object. It seems likely to me, given the fact that space seems to emit photons of its own accord, that electrons (very occasionally) tunnel to great distances from their host atoms, and that, given how often they'd be tunneling in general, these incredibly rare occurrences actually become somewhat routine. In any case, if these photons are in intergalactic space, the clear implication is that they have 'struck something' in our galaxy/cluster.
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If Hawking radiation were to be anything, it would almost certainly be gamma-ray photons.
Nope.
Go and look it up.
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Ok, what would it be other than gamma-ray photons then? I'll grant you neutrinos and some more massive particles may escape organically via quantum tunneling though, in the case of quarks and hadrons, I suspect they wouldn't make it very far away from the event horizon before being drawn back in due to the black hole's overwhelming gravity. Neutrinos might get further; then again, what I suspect about background electrons and the neutral currents leading to neutrino oscillations might impede a neutrino's progress beyond the event horizon; then again, it might not. In any case, any and all photonic radiation (either incoming or outgoing) near an event horizon will be de facto gamma radiation due to the blueshifting near the horizon. See these two papers on the gamma-ray signals from primordial black holes:
https://arxiv.org/pdf/2110.05637.pdf
https://academic.oup.com/mnras/article/283/2/626/988213
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Ok, what would it be other than gamma-ray photons then?
Black body radiation, so photons.
The spectrum depends on the temperature, and thus the size of the BH. For all but the smallest holes, the temperature is below that of the cosmic background. So the emissions are in the microwave and redo frequency spectrum
But, if you don't know these basic things about the subject, why are you posting tosh, rather than learning facts?
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"Black body radiation, so photons." and what wavelength would these photons be given the gravitational potential energy they're subject to near a black hole event horizon? We know that photons lose energy and are shifted into the red end of the EM spectrum as objects move away from us. This corresponds to a weakening of the gravitational influence over these photons due to the recession in space of the bodies from which they're emitted. The exact opposite happens in very strong gravitational fields. Photons furthermore fall into superposition with other (already very high-energy) photons creating superposed 'particles' or perhaps even 'photon fluids' or 'photon-plasmas' very close to black hole event horizons whose energies are (as I've alluded to) already very high. Granted, as photons escape the pull of a black hole, they may lose energy via redshift. However, at the point of being emitted, they are gamma rays. They might remain gamma rays for some time, but, depending on where in space they're emitted (i.e. depending on the gravitational potential of their background) they might be subject to greater or lesser degrees of redshift. But thank you for your condescending (and self-contradicting) comment. Perhaps you ought to stick to chemistry. https://astronomy.swin.edu.au/cosmos/g/Gravitational+Redshift
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Also, take some more unsolicited advice. Next time you make an assertion to me, try and back it up with some sources.
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We are talking about Hawking radiation.
From the point of view of Prof Hawking (a long way from any black holes) the radiation is in the form of a black body spectrum; it's not gamma rays.
Since you insist on a reference.
"Hawking radiation is thermal radiation that is theorized to be released outside a black hole's event horizon because of relativistic quantum effects."
https://en.wikipedia.org/wiki/Hawking_radiation
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You are choosing the wrong hill to die on.
https://energyeducation.ca/encyclopedia/Radiant_heat#:~:text=Radiant%20heat%2C%20also%20known%20as,(unlike%20convection%20and%20conduction).
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and what wavelength would these photons be given the gravitational potential energy they're subject to near a black hole event horizon?
That depends upon the mass of the black hole. The more massive the hole, the longer the wavelength of the photons. This calculator can be used to determine the wavelength of the peak photons emitted as Hawking radiation: https://www.vttoth.com/CMS/physics-notes/311-hawking-radiation-calculator
For a black hole of 3 solar masses (and radius of about 8.86 kilometers) , the peak photon wavelength is about 178.5 kilometers. That's well into radio wave territory. If you want to get a black hole with gamma rays as the peak wavelength (about a picometer or less), then the black hole would need to have a mass on the order of 3.34 x 1010 metric tons and have a radius of about 49.66 femtometers. So stellar mass black holes and above are primarily radio emitters, not gamma emitters. Primordial black holes, should they exist, could be much smaller and thus plausible gamma emitters.
In any case, any and all photonic radiation (either incoming or outgoing) near an event horizon will be de facto gamma radiation due to the blueshifting near the horizon.
That's not true. Photons are blueshifted when moving towards a source of gravity and redshifted when moving away. Your link about gravitational redshift even confirms this:
Einstein’s theory of general relativity predicts that the wavelength of electromagnetic radiation will lengthen as it climbs out of a gravitational well. Photons must expend energy to escape, but at the same time must always travel at the speed of light, so this energy must be lost through a change of frequency rather than a change in speed. If the energy of the photon decreases, the frequency also decreases. This corresponds to an increase in the wavelength of the photon, or a shift to the red end of the electromagnetic spectrum – hence the name: gravitational redshift. This effect was confirmed in laboratory experiments conducted in the 1960s.
The exact opposite happens in very strong gravitational fields.
Please provide a source for this, as it contradicts what your link says. According to your link, gravitational redshift should become stronger with increasing mass because a photon would have to expend more energy to climb up against a stronger gravitational field.
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You are choosing the wrong hill to die on.
https://energyeducation.ca/encyclopedia/Radiant_heat#:~:text=Radiant%20heat%2C%20also%20known%20as,(unlike%20convection%20and%20conduction).
What point were you trying to make?
I'm guessing that only one of us is actually a spectroscopist.
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That you seem ignorant of the fact that gamma rays can impart heat to an object.
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I had a look at one of the references.(labeled as [2] in the OP.)
"There can be no dark energy or space expansion because radiation pressure forces can cause the universe to expand
G Zhang1 and X Wang2"
There's a copy here
https://iopscience.iop.org/article/10.1088/1742-6596/2014/1/012010
And the essential claim is
"calculations show that the sun's total gravitational forces towards the entire universe, excluding nearby galaxies, is 1.645×10^19N, while the sun's average total radiation pressure force is 1.33×10^21N. So, the sun's radiation pressure force is much (80 times) larger than its gravitational force. "
Well that's interesting.
Imagine I consider the Earth.
Near the Earth, the Sun's radiation pressure is about 4.5 µ Pa
So the total force on the Earth is about 500,000,000 Newtons
And the gravitational attraction between them is 3.67 x 10^22 newtons
So, for the Earth, we know that the gravity beats the solar pressure. (Just as well really, or we wouldn't be here.)
The ratio is about 14 orders of magnitude.
Interestingly, both effects scale as 1/R^2 so the ratio would stay the same even if we considered a hypothetical Earth at a different distance from the Sun.
Imagine we consider a smaller planet - 1/10 the size of the Earth, but otherwise similar (i.e the same density).
It would have a hundredth of the area so the solar force would be 1/100 as big.
But the mass would be 1/1000 of that of Earth.
So the ratio of radiation pressure force to gravitational force would be 10 times smaller.
And in general, for an object X times smaller than Earth, the ratio would be X times smaller than 10^14
So, for an object 10^14 times smaller than the Earth, the solar radiation pressure would exceed the gravitational effect (assuming it was made of the same stuff that the Earth is.)
So for a particle with a radius less than about 64 nm the net effect is repulsive.
So it looks kind of plausible.
But consider some grain of sand in outer space; the Sun attracts it (overall) as long as it's bigger than something like 100nM across.
The Sun also attracts everything in the shadow of that particle
But the Sun does not shine on anything in the shade. So those things in shade only experience an attractive force.
Moreover, the sand grain attracts stuff towards it.
In the same way that the Earth can hold an atmosphere (made of particles far smaller than 100 nm) the dust grain acts as a "relay" for the Sun's attraction.
So, overall, I'm far form convinced that the overall effect of the Sun is repulsive.
It isn't for anything that's bigger than 100 nm or so. (I'm not worried about the odd order of magnitude)
And it isn't for small particles near big things (like the atmosphere).
And I think that covers quite a lot of the universe- everything in the milky way is "near" the SMBH in the middle of it. (Though the density is smaller, someone else can do that arithmetic for me, if they can be bothered).
But Black holes still won't emit gamma rays as Hawking radiation .
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That you seem ignorant of the fact that gamma rays can impart heat to an object.
How did you come to that absurd conclusion?
Where did I say anything that looked like I said anything about the effects of gamma rays?
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The radiation pressure force is acting between galaxy clusters, so the sun's gravity is somewhat irrelevant in this context. You need to consider the fact that the sun is very far away from the recesses of space between galaxy clusters where this radiation will have been building up for billions of years. Also, the research I linked to clearly states that primordial black holes have been observed to evaporate in a burst of gamma radiation. That *is* Hawking radiation. Also, because you said this (to respond to your second (somewhat chippy) response). Black body radiation, so photons.
"The spectrum depends on the temperature, and thus the size of the BH. For all but the smallest holes, the temperature is below that of the cosmic background. So the emissions are in the microwave and redo frequency spectrum"
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In any case, any and all photonic radiation (either incoming or outgoing) near an event horizon will be de facto gamma radiation due to the blueshifting near the horizon.
That's not true. Photons are blueshifted when moving towards a source of gravity and redshifted when moving away. Your link about gravitational redshift even confirms this:
You're just reiterating what I said. In the presence of a very strong gravitational field (i.e. near an event horizon), any photons in the vicinity, whatever their wavelength, and whether or not they're incoming or outgoing photons, will be BLUESHIFTED due to the gravity. I grant you, if a photon somehow manages to move sufficiently far out of a gravitational field (as I believe I've already mentioned) then it may well become redshifted and you'd have your microwave or radio wave radiation. The overwhelming majority of Hawking radiation photons will be emitted somewhat close to the black hole's horizon, their likelihood of further escape from the black hole's gravity is actually somewhat negligible; granted, also, any photons we OBSERVE coming from a black hole are also; granted, more than likely; going to have been REDSHIFTED at some point.
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Also, granted, Toth's calculator seems reasonable. Smaller black holes evaporate very quickly and, hence, we'd observe gamma rays coming from them. For larger black holes their radiation, at the point of emission, would be in the gamma spectrum and almost all of it would fall back into the BH due to its overwhelming gravity. Perhaps no one here is wrong, per se, and we're talking somewhat at cross purposes, but the truth stands; HR is always gamma rays initially unless said radiation gets far enough away from the black hole to allow it to become redshifted.
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No, merely being near a strong source of gravity does not blue shift anything. Moving further into the gravity well will blue shift the light, whereas light moving up and out of the gravity well will be redshifted.
No, Hawking radiation is not always gamma rays. Go look at that calculator I linked. Photons with a wavelength in the range of kilometers absolutely are not gamma rays.
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Being near a strong gravity source would blueshift the light. That's sort of one of the basic underlying truths of general relativity. If gravity in an area is getting stronger; if, for instance, one galaxy is moving towards another; more gravity is acting on the light and hence its wavelength shrinks, and its frequency increases. The reverse is true in redshift. You admit as much yourself, and you sort of undermine your own point in doing so. As a galaxy recedes from other galaxies, creating space in between them, the light entering that space is experiencing progressively less gravity and is therefore redshifted. I also acknowledged the validity of Toth's calculator and explained why it gives the results that it does. I can't understand why we're arguing about this.
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Again, no. Whether or not a photon is blue shifted or red shifted depends on whether or not it is moving into or out of a gravity well. Stating that a photon is blue shifted because it is near a strong source of gravity is incorrect because you have not defined the direction of movement.
If you acknowledge the accuracy of the calculator, then you accept that stellar mass black holes produce primarily radio waves, not gamma rays.
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Well, is a photon deposited just beyond the event horizon of a black hole moving "into" or "out of" a strong gravitational field?
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That depends upon its direction of travel. Some will be traveling towards the hole before passing the event horizon. Those would be blue shifted. Some will be moving away from the black hole and thus red shifted.
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No, we were talking about Hawking radiation. Yes, incoming radiation will be blueshifted, but any radiation deposited near the event horizon will also be blueshifted. If, in the unlikely event a photon deposited near the event horizon of a strongly-gravitating black hole were to escape the gravity of a black hole to a degree sufficient to allow it to redshift, then it would become redshifted. That does not mean that the photon is not a gamma photon at the point of being emitted by the black hole; it means only that any radiation we observe coming from sufficiently large black holes is microwave or radio wave radiation. The implication here is that this radiation has been allowed to travel a sufficient distance from the black hole to allow it to be redshifted. Because it is, in general, very unlikely that any radiation can escape a black hole's gravity, we only observe black holes in the radio/microwave part of the EM spectrum. As for smaller black holes (and larger black holes, when they eventually evaporate) radiate away (which they do so far more quickly than a larger BH) they give off a burst of gamma rays. This much is well-established. Giving a probabilistic underpinning to the phenomenon of Hawking radiation and the information escape paradox; through invoking an idea of gravitational electron densities (i.e. clouds of electrons forming gravitational fields); allows us to gain some quantum-gravitational perspective on this matter. In standard GR, Hawking radiation would never be possible; any light emitted at the horizon would just fall straight back in. In a quantum conception of gravity, there exists (I guess) a small probability of a photon emitted by the black escaping its gravity entirely. This is because it might be reflected by these background electrons in just the right way, or hit the right sequence of electrons that don't absorb it again (if, say, their energy levels are too high), and by a quirk of fate it manages to escape (which, as I've said, is very unlikely for very massive black holes). That said, I grant you that, if it does manage to escape, it will probably undergo redshift and eventually become a micro- or radio wave photon.
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I'm still waiting for a reasonable reply to this.
Where did I say anything that looked like I said anything about the effects of gamma rays?
primordial black holes have been observed to evaporate in a burst of gamma radiation. That *is* Hawking radiation
Can you show where anyone has observed the evaporation of a primordial BH?
Also, do you not realise that the radiation is emitted over the life of the BH, not at the end.
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Well, is a photon deposited just beyond the event horizon of a black hole moving "into" or "out of" a strong gravitational field?
If it falls in then we don't get to see it.
If it is Hawking radiation then comes out .
And if it comes out it has to "climb" out against the gravitational pull of the BH and will be red shifted.
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Perhaps no one here is wrong, per se, and we're talking somewhat at cross purposes, but the truth stands; HR is always gamma rays initially unless said radiation gets far enough away from the black hole to allow it to become redshifted.
But it's only HR after it has left the BH.
When it's created it's annihilation radiation.
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https://academic.oup.com/mnras/article/283/2/626/988213?login=false
I think 'can' is the operative word here. I suspect primordial black holes are likely and that we've observed their evaporation in the gamma-ray bursts detailed in this paper. I also suspect the LHC detection of two gamma-ray photons as the decay products of the so-called Higgs boson were the decay products from a naked singularity (which would be consistent with our theories on black hole physics). Perhaps the term 'observed' was a little strong on my part. Also, perhaps you weren't suggesting that gamma rays couldn't act as thermal radiation, though at the time you seemed to be. The point I was driving at with Hawking radiation is that any radiation emitted by a black hole near its event horizon is Hawking radiation. This is true if it's a small black hole that quickly evaporates or a large one that takes eons to evaporate. In the case of small black holes, we'd see a burst of gamma rays (since it has less gravity to pull the radiation back in); in the case of larger black holes, we'd see only radio waves or microwaves since only a small proportion of that radiation is able to escape the huge forces of the black hole's gravity field and will become redshifted in the unlikely event it escapes to a sufficient distance to be observed. In either case, the radiation is still Hawking radiation, and it still all starts out as gamma rays.
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Also, perhaps you weren't suggesting that gamma rays couldn't act as thermal radiation, though at the time you seemed to be.
How did you come to that mistake?
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Perhaps the term 'observed' was a little strong on my part.
Because it simply isn't true, is it?
Show me the reports of observations of gammas from primordial BH, or admit that what you said was not true.
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we'd see a burst of gamma rays
The calculator shows how long that "burst" would be.
A 3.34 E 10 tonne BH would emit gammas.
The lifetime is about a million times longer than the history of the universe.
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Anything smaller than that would also. Anything larger than that would also. What we detect from anything larger than that (or, 'much larger) would be INITIALLY gamma radiation undergoing a subsequent redshift. I don't think there's much more that needs to be said.
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I see you told Bored Chemist to post a source for his claims. I would now like to ask you to do the same. Please post a source that supports your claim that Hawking radiation starts off as gamma rays.
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https://link.springer.com/article/10.1007/BF02676709?noAccess=true
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It would be anyway because of GR.
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That link is about primordial black holes. I am talking about stellar mass and supermassive black holes.
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The size of the black hole is irrelevant. I think I've basically pointed this out already. So I don't start sounding like a broken record, perhaps I'll try and put it somewhat differently. From what theory tells us about smaller black holes, we infer that larger black holes, as they evaporate away, will end their lives in a burst of gamma radiation. Prior to that point, they are giving off gamma radiation, all the time; the overwhelming majority of it falls straight back into the black hole, some manages to escape the black hole's colossal gravitational forces, and find its way into space whereupon it's become redshifted. Any photons 'created' (again, a notion I reject; though my rejection of it is not so relevant in this argument) anywhere close to the event horizon of a black hole will be subject to huge gravitational forces and, hence, blueshifting. Again, some do manage to escape and become redshifted eventually. In any case, they start out as gamma photons. I suspect this comes down to the collosal forces present in black hole interiors due to their huge densities and pressures; any photon caught up in all that material (whatever it is; quark-gluon plasma, or whatever) will, of course, be, in essence, blueshifted.
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Any photons 'created' (again, a notion I reject; though my rejection of it is not so relevant in this argument) anywhere close to the event horizon of a black hole will be subject to huge gravitational forces and, hence, blueshifting.
If we see it then it has got out of the BH and will have been red shifted.
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As I said, yes.
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As I said, yes.
What you very clearly said was
Any photons 'created' (again, a notion I reject; though my rejection of it is not so relevant in this argument) anywhere close to the event horizon of a black hole will be subject to huge gravitational forces and, hence, blueshifting.
Do you realise that blue is not red?
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This is becoming tedious. Yes, any photons emitted near the event horizon will be experiencing blueshift. If, in the incredibly unlikely event that they bounce off all the right background particles, in the right order, and probability allows them the (very, very) unlikely opportunity to escape the black hole's gravity sufficiently to allow them to become redshifted, they will be redshifted.
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This is becoming tedious. Yes, any photons emitted near the event horizon will be experiencing blueshift. If, in the incredibly unlikely event that they bounce off all the right background particles, in the right order, and probability allows them the (very, very) unlikely opportunity to escape the black hole's gravity sufficiently to allow them to become redshifted, they will be redshifted.
And if they don't then they are not part of Hawking radiation.
But the problem is still there.
You keep saying "any photon" when you might possibly get away with saying "most photons".
We are only talking about a tiny fraction of possible photons.
That's why black holes are pretty nearly black.
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Stop. We are going round in circles, you're not really interested in the issues here or advancing the discussion; you're only interested in splitting hairs and getting the last word. I'm tempted to let you have it. However, please don't try misleading people into believing that only the radiation that escapes a BH's gravity is Hawking radiation. The mode of particle 'creation' described by Hawking would be going constantly near black hole event horizons and ALL those photons ARE Hawking radiation. However, of course, we only observe a tiny number of said photons since it's HIGHLY UNLIKELY that any will escape a black hole's gravity. They are ALL Hawking radiation though. They all rely on the same mechanism of putative particle-antiparticle 'creation' and 'annihilation' described in Hawking's work. That is the end of it.
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The size of the black hole is irrelevant. I think I've basically pointed this out already.
Not according to Hawking's equation, it isn't.
Prior to that point, they are giving off gamma radiation, all the time
Again, provide a source that this applies to all black holes, regardless of size.
will be subject to huge gravitational forces and, hence, blueshifting.
That's not how that works. Blue shift and red shift imply a shift in wavelength. A shift in wavelength means that the wavelength has changed from one value to another. However, the photons in Hawking radiation literally start off near the horizon. It's not like they were transported there from somewhere else. If you claim that the wavelength of those photons is blue shifted, then what are they blue shifted from? What was their previous wavelength? They can't have one, because they didn't exist before.
Here is Hawking's original paper about Hawking radiation: https://www.brainmaster.com/software/pubs/physics/Hawking%20Particle%20Creation.pdf
Hawking confirms here that a black hole of solar mass is actually very cold:
For a black hole of solar mass (1033 g) this temperature is much lower than the 3 °K temperature of the cosmic microwave background.
An object that cold does not emit gamma rays as thermal radiation. He also confirms that tiny black holes on the verge of evaporating are very hot:
As they got smaller, they would get hotter and so would radiate faster. As the temperature rose, it would exceed the rest mass of particles such as the electron and the muon and the black hole would begin to emit them also. When the temperature got up to about 1012 °K or when the mass got down to about 1014 g the number of different species of particles being emitted might be so great [11] that the black hole radiated away all its remaining rest mass on a strong interaction time scale of the order of 10-23 s. This would produce an explosion with an energy of 1035 ergs. Even if the number of species of particle emitted did not increase very much, the black hole would radiate away all its mass in the order of 10-28M3 s. In the last tenth of a second the energy released would be of the order of 1030 ergs.
Now 1012 K is definitely hot enough to emit gamma rays.
So I have a source here, from Hawking himself, that says large black holes are cold and small black holes are hot. He does not say in his paper that all black holes are very hot gamma emitters. So I've provided a source against the gamma ray claim of yours. Can you provide a source that shows this is wrong?
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We are going round in circles. Please review this thread and reflect on how I've addressed these issues in the previous posts.
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We are going round in circles. Please review this thread and reflect on how I've addressed these issues in the previous posts.
What you said was incorrect. You claimed that all black holes produce gamma rays, regardless of size, and that those gamma rays are red shifted by gravity to longer wavelengths like radio waves. That position is not supported by Hawking's paper.
Can you explain how an object with a temperature much less than 3 kelvins (which is the temperature of stellar mass black holes, as per Hawking's paper) can emit gamma rays as thermal radiation? And no, blue-shifting is not the answer.
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I already have.
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Assuming some hadronic, or leptonic component within the vicinity of black holes which, with consideration given to their sheer masses (and everything we know about gravity), and the probable electric charge of their constituent particles/fields, we can reasonably infer that their gravitational fields are composed of electrons. Building from what we understand about neutron stars, and their lattice structures of neutrons with free electrons moving within the lattice, and the 'protons' (or the single, giant proton QGP core) in their core, we can make some reasonable assumptions about a black hole; i.e. if anything like a QGP forms the outer layer of a black hole (i.e. something that's positively charged) then it's overwhelmingly likely that something negatively charged orbits that positively charged thing. The same is true of all structures we observe in particle physics, from the hydrogen atoms to the neutron star. A positive charge is almost always accompanied with a negative charge orbiting it.
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I already have.
Please quote where you have (and more importantly than anything else, the source that supports your claim that all black holes make gamma rays).
we can reasonably infer that their gravitational fields are composed of electrons.
Gravitational fields are not made of electrons.
if anything like a QGP forms the outer layer of a black hole (i.e. something that's positively charged)
It doesn't. Black holes don't have an "outer layer". The event horizon is not a physical object.
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https://arxiv.org/abs/2110.05637#:~:text=Evaporating%20Primordial%20Black%20Holes%20in%20Gamma%20Ray%20and%20Neutrino%20Telescopes,-Antonio%20Capanema%2C%20AmirFarzan&text=A%20primordial%20black%20hole%20in,gamma%20ray%20and%20neutrino%20telescopes.http://philsci-archive.pitt.edu/17588/1/Einstein%27s%20redshift%20derivations%20-%20preprint.pdfhttps://adsabs.harvard.edu/full/1968Obs....88...91Shttps://en.wikipedia.org/wiki/Redshift
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"Gravitational fields are not made of electrons." unjustified assertion. In terms of neutron star physics, it's highly unlikely they could be made of anything else. Their core is a bloody atomic nucleus (in essence) dude, think!
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Or, rather, the neutron star IS an atomic nucleus writ large; what we believe is the 'star' is just a neutron lattice with free electrons moving between the lattice structure and a QGP in its deeper laters (made, I suspect, mostly of up quarks); the electrons forming the gravitational fields are extraneous instances of the election's wavefunction being 'observed' by some particle showing up to interact with it/collapse its wavefunction beyond what we observe as the 'physical' boundaries of that sort of star.
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Also, I enjoy how you're distracting yourself with this quibbling over Hawking radiation and not addressing my point on dark energy (which was the original topic I was, here, intending to discuss). Nothing about the Casimir force also. Interesting.
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https://arxiv.org/abs/2110.05637#:~:text=Evaporating%20Primordial%20Black%20Holes%20in%20Gamma%20Ray%20and%20Neutrino%20Telescopes,-Antonio%20Capanema%2C%20AmirFarzan&text=A%20primordial%20black%20hole%20in,gamma%20ray%20and%20neutrino%20telescopes.http://philsci-archive.pitt.edu/17588/1/Einstein%27s%20redshift%20derivations%20-%20preprint.pdfhttps://adsabs.harvard.edu/full/1968Obs....88...91Shttps://en.wikipedia.org/wiki/Redshift
That's about primordial black holes. If there is a statement in there somewhere which states that all black holes produce gamma rays, then please quote it. Until you supply a source that states stellar mass and supermassive black holes emit gamma rays, you have not supplied what I have asked for.
"Gravitational fields are not made of electrons." unjustified assertion. In terms of neutron star physics, it's highly unlikely they could be made of anything else. Their core is a bloody atomic nucleus (in essence) dude, think!
You might want to study general relativity. Einstein said nothing about gravity being made of electrons. I'm not aware of any other physicist who has claimed that either. If you know of any, please link them.
Also, I enjoy how you're distracting yourself with this quibbling over Hawking radiation and not addressing my point on dark energy (which was the original topic I was, here, intending to discuss). Nothing about the Casimir force also. Interesting.
Admittedly, I'm not sure how radiation pressure could lead to space expanding. Radiation pressure pushes on matter, not empty space. This also seems a poor solution for an accelerating expansion because the radiation pressure should get weaker as galaxies move further apart from each other. Less pressure should lead to a deccelerating expansion, not an accelerating one.
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Oh, what, you think I haven't studied general relativity? How condescending. The problem with you people is that you believe that every theory in physics is 100% true. Newton's law of gravity is not 100% true, hence we have GR. We know GR is not 100% true, hence we have quantum gravity theories. This is GR dogmatism.
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Oh, what, you think I haven't studied general relativity?
Describing gravity as being made of electrons, under any circumstances, doesn't make sense in light of relativity.
The problem with you people is that you believe that every theory in physics is 100% true.
No, I don't. I'm well aware that our modern theories have shortfalls. However, the idea that gravity is made of electrons isn't a solution to whatever problem relativity may have.
hence we have quantum gravity theories.
Which, unfortunately, have not yet been successful.
This is GR dogmatism.
General relativity is currently our best theory to explain gravity. It is extremely well supported by observation. That's why it's the current default position. If it is to be replaced, the new theory has to explain everything it can explain and then some.
I don't understand how you can reason that gravity can be made out of electrons. How can electrons produce gravitational attraction between two different masses?
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Well, gravity is a force, and hence not 'made' of anything. So, I suppose you're correct on that. However, gravitational fields are, I suspect, electron densities. And it does make sense in light of general relativity.
"If it is to be replaced, the new theory has to explain everything it can explain and then some." What like 'dark matter', 'dark' energy, and the information escape paradox? I'm relatively (no pun intended) certain invoking electron densities as gravitational fields could explain these things. That's sort of the point of the paper I've written. Again, I might not be correct; however, since there are three major quantum gravity theories, and it stands to reason they couldn't all be correct, and they were all hatched by genius physicists (of whom Stephen Hawking was one, Roger Penrose another and Leonard Susskind yet another), it seems being wrong in physics is ok. Having said that, you're just asserting that this idea of mine isn't compatible with relativity, you're not even giving an explanation as to why it isn't.
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However, gravitational fields are, I suspect, electron densities.
How does that explain gravity (especially the observation that gravitational strength is associated with mass, not with the number of electrons)?
Having said that, you're just asserting that this idea of mine isn't compatible with relativity, you're not even giving an explanation as to why it isn't.
Because relativity successfully models gravity as a distortion of space-time (backed up by experiments that measure gravitational time dilation and the like), not as electron density.
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Fully explaining my theory here is somewhat beyond the scope of this post, but feel free to check out my draft papers on academia.edu and I've posted some videos on this topic on YouTube. I'm currently trying to get a book together on this topic.
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I see you posted a thread about that here back in 2017 (I think). Is it still the same or have you updated it since then?
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Yeah, roughly. It's undergone quite a bit of refinement since then. It could possibly do with finessing a bit further, but I think I'm more or less ready to put it in book form and publish it (and then have no one read it).
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Fully explaining my theory here is somewhat beyond the scope of this post
That's good. A full explanation of how electron density is gravity would probably blowup everyone bologna meters...
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Fully explaining my theory here is somewhat beyond the scope of this post
I'm pretty sure that puts this thread on the wrong side of the rules.
Certainly, many fora require that the discussion takes place without having to go to other sites to see what the question is.
Posting "this is true, but I'm not explaining why" is too close to preaching.
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I'm pretty sure that puts this thread on the wrong side of the rules.
Certainly, many fora require that the discussion takes place without having to go to other sites to see what the question is.
Posting "this is true, but I'm not explaining why" is too close to preaching.
He has another thread where he does explain his thoughts on that: https://www.thenakedscientists.com/forum/index.php?topic=70600.msg516449#msg516449
I plan on reading it and posting my subsequent responses about his gravity ideas there. The radiation pressure and and black hole stuff is fine to keep discussing here.
As an aside, I want to apologize to samcottle for what he took to be a condescending comment. I see now, after looking at his other thread, that his comment about gravity being made of electrons isn't what I thought it originally meant.