Taking a Fresh Look at the Physics of Radiometers.
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From: Timo Nieminen on 1 Jun 2010 00:24 On Mon, 31 May 2010, Tim BandTech.com wrote: > On May 30, 2:58 pm, Sam Wormley <sworml...(a)gmail.com> wrote: > > On 5/30/10 9:31 AM, NoEinstein wrote: > > > > > Photons have ZERO mass, and exert zero force upon > > > âstrikingâ a reflecting surface. > > > > Photons have zero REST mass, but have momentum of > > > > p = hν/c = h/λ > > > > A perfect reflector's momentum would increase by > > > > 2p = 2h/λ > > > > for every photon. Ever heard of a solar sail? > > I've recently done some research on the radiometer, and this math > analysis is definitely not what makes it tick. The sun is putting out > 1300 watts per square meter. If all of this energy goes into > mechanical energy then we'd be making turbines rather than PV cells. Apart from some very early claims about the Crookes radiometer (such as by Crookes), shown to be wrong a few years later, and their modern repetition, who claims that radiation pressure makes the radiometer tick? 1300W per square metre means 9 micronewtons per square meter, on a perfect reflector. That it would take a square kilometer to be able to use solar radiation pressure to produce the same force as the weight of 1kg pretty much says why we don't do this. (A little more at the bottom of post.) > There is a 'radiation pressure' claim of one third the energy density > (loose language) supposedly from Maxwell. I haven't found that > computation yet. Try Maxwell's Treatise. Art 792, pp 391-392 in 1st edition. > I'm pretty sure the radiation pressure argument is false. Photons are > more like AC sources than DC sources. If the pressure is alternating > then to claim a propulsive acceleration is a misnomer. It would be > like putting a ping pong ball in front of a speaker, blasting out 100 > watts and expecting the ping pong ball to accelerate away from the > speaker. Why not? Just don't expect a large acceleration; I don't think that 100W would be enough to levitate against gravity. It's been done, google or youtube for "acoustic levitation". > The most blatant farce is in terms of conservation of energy. The > claim is that the light hitting a reflective surface will provide > twice the momentum; one kick when the light hits it and one kick again > from the light when it leaves. This concept offends the conservation > of energy. 1300 watts in with 1300 watts out leaves no acceleration > whatsoever for the perfect reflector. If the reflector is moving, there will be a Doppler shift, and energy in will be different from energy out. If the reflector is stationary, then you could have, e.g., 1300W in and 1300W out. But no work would be done. Even better, if the light is slowing the reflector down, the reflected light has more energy than the incident light. Just as one would expect from conservation of energy. Back to the idea of using solar radiation to produce mechanical energy. If you can move the 1 square kilometer reflector at 1km/s downwards, then you'd get a power of 9kW, from a total of 1.9GW input solar power. This is very poor efficiency compared to even poor solar cells. -- Timo
From: Tim BandTech.com on 1 Jun 2010 08:22 On Jun 1, 12:24 am, Timo Nieminen <t...(a)physics.uq.edu.au> wrote: > On Mon, 31 May 2010, Tim BandTech.com wrote: > > On May 30, 2:58 pm, Sam Wormley <sworml...(a)gmail.com> wrote: > > > On 5/30/10 9:31 AM, NoEinstein wrote: > > > > Photons have ZERO mass, and exert zero force upon > > > > âstrikingâ a reflecting surface. > > > Photons have zero REST mass, but have momentum of > > > p = hν/c = h/λ > > > A perfect reflector's momentum would increase by > > > 2p = 2h/λ > > > for every photon. Ever heard of a solar sail? > > I've recently done some research on the radiometer, and this math > > analysis is definitely not what makes it tick. The sun is putting out > > 1300 watts per square meter. If all of this energy goes into > > mechanical energy then we'd be making turbines rather than PV cells. > Apart from some very early claims about the Crookes radiometer (such as > by Crookes), shown to be wrong a few years later, and their modern > repetition, who claims that radiation pressure makes the radiometer tick? The Nichols radiometer is claimed by some to work in a vacuum, including Nichols himself. Here is a link to his original work which I'm snipping from a few weeks ago of that past thread: Here is a quote from Nichols published work: "At the close of the pressure and energy measurements when the reflecting power of the silver faces of the vanes was compared with that of the glass silver faces the reflection from the silver faces was found very much higher than that for the glass faces backed by silver. This result was the more surprising because the absorption of the unsilvered vanes was found by measurement to be negligibly small. This unexpected difference in reflecting power of the two faces of the mirrors prevented the elimination of the gas action by the method described from being as complete as had been hoped for. But by choosing a gas pressure where the gas action after long exposure is small the whole gas effect during the time of a ballistic exposure may be so reduced as to be of little consequence in any case." - http://books.google.com/books?id=8n8OAAAAIAAJ&pg=RA5-PA327&dq=torsion... E.F. Nichols and G.F. Hull, The Pressure due to Radiation, The Astrophysical Journal,Vol.17 No.5, p.315-351 (1903) There is a standard claim that the Nichols radiometer is operating on different principles than the Crookes radiometer, but this passage exposes that gas effects were never eliminated, and furthermore, if the Nichols radiometer truely operated in vacuum, then why shouldn't the Crookes? This question seems to go unanswered, and is to me a sore point. The stranger reversal in deflection from .05 mm Hg to .02 mm Hg seems to go observed yet unanswered within the analysis. Nichol's seems to have pushed for a specific result, and having gotten it, is happy not to look back. Is this science? The link is worth the read but above I've quoted a passage that my skepticism picks upon. Periods were missing, and this text is coming straight from Google's 'cut feature of their image reader; pretty damn slick and righteuous that we've got access to this information. If all journals would do this... I guess they will in time; that is, those that do not wish to exclude amateurs from access. To amplify the contradiction of the quote I pick out two portions: "the mirrors prevented the elimination of the gas action by the method described from being as complete as had been hoped for" "the whole gas effect during the time of a ballistic exposure may be so reduced as to be of little consequence in any case" There is no data demonstrating these nulls, and the sharp inversion from the 0.02 to 0.05 suggests some sort of nonlinearity at that null, which will prevent stable experimentation. Anyway, selection of that null should actually yield no results. The dynamics exposed by the experiment go ignored in the analysis. I do not feel strongly enough to declare a farce here, but I am leaning in that direction. (end of copy from recent prior thread) > > 1300W per square metre means 9 micronewtons per square meter, on a > perfect reflector. That it would take a square kilometer to be able to use > solar radiation pressure to produce the same force as the weight of 1kg > pretty much says why we don't do this. Yes, well, I'd like to understand how even this slight figure comes about. It is easy to falsify the e=hv momentum claim (which is a big enough statement) but even this slender acceleration is questionable by the argument on conservation of energy. > > (A little more at the bottom of post.) > > > There is a 'radiation pressure' claim of one third the energy density > > (loose language) supposedly from Maxwell. I haven't found that > > computation yet. > > Try Maxwell's Treatise. Art 792, pp 391-392 in 1st edition. OK. http://posner.library.cmu.edu/Posner/books/pages.cgi?call=537_M46T_1873_VOL._2&layout=vol0/part0/copy0&file=0418 Thank you Timo for such a clean reference. There is a square within the expression that is rectifying the wave. If we were to attempt an instantaneous measurement of acceleration then I think the result would read more true. I only just started studying this and it does rely on much of the previous content. Also I haven't made it to the one third argument. Why oh why would we rely upon a volume figure to assess the force on a plate? The figuring does not extend generally either. For instance, staying with Watts and Joules and seconds what if we consider a one second interval of the solar power? Now rather than a 1mx1mx1m box we have a box extending 3e8 meters toward the sun, and now the computation gets trickier, for the assumption on this 1kJ box of energy now has to worry about the proximity to the sun. I am not familiar with modern physics using the electokinetic energy versus electrostatic energy. What seems most familiar is e = h v where v is proportional to the frequency of a supposed photon. You seem to have validated that photon momentum is not responsible for the radiation pressure. I'm honestly not clear on whether you are in support of a mechanical pressure or not. This does not really matter, but because the ballistic theory of light and black body principles rest nearby, then there is some cause for interest beyond the toy light-mill's functionality. I believe it is accurate to translate the 1300 W/m/m of the sun directly into photon energy. If one photon e = h v is a bullet then how much force does it impart? Is Wormley correct? Then why doesn't it translate? You see, we are knocking on the back of the black door. > > > I'm pretty sure the radiation pressure argument is false. Photons are > > more like AC sources than DC sources. If the pressure is alternating > > then to claim a propulsive acceleration is a misnomer. It would be > > like putting a ping pong ball in front of a speaker, blasting out 100 > > watts and expecting the ping pong ball to accelerate away from the > > speaker. > > Why not? Just don't expect a large acceleration; I don't think that 100W > would be enough to levitate against gravity. > > It's been done, google or youtube for "acoustic levitation". OK. http://www.youtube.com/watch?v=veM5nZNBoW8&feature=PlayList&p=4BD5157AEF748135&playnext_from=PL&playnext=1&index=24 This isn't quite what I had in mind. Particularly at the Earth's distance from the sun we are not free to rely upon access to the sun itself within our argument, though I will get near to this below. > > > The most blatant farce is in terms of conservation of energy. The > > claim is that the light hitting a reflective surface will provide > > twice the momentum; one kick when the light hits it and one kick again > > from the light when it leaves. This concept offends the conservation > > of energy. 1300 watts in with 1300 watts out leaves no acceleration > > whatsoever for the perfect reflector. > > If the reflector is moving, there will be a Doppler shift, and energy in > will be different from energy out. If the reflector is stationary, then > you could have, e.g., 1300W in and 1300W out. But no work would be done. Very good. We have agreement, particularly at the low velocities that these instruments work at. As far as we can tell there is no reliance upon red shifting of light, which could provide some work. - Tim > > Even better, if the light is slowing the reflector down, the reflected > light has more energy than the incident light. Just as one would expect > from conservation of energy. > > Back to the idea of using solar radiation to produce mechanical energy. If > you can move the 1 square kilometer reflector at 1km/s downwards, then > you'd get a power of 9kW, from a total of 1.9GW input solar power. This is > very poor efficiency compared to even poor solar cells. I'm still trying to understand how to arrive at your 9kW figure, other than copying other's work. It is a strange figure to me to arrive at which somehow depends upon a volume, even though the surface is not a volume. This makes me think (not joking either) of space creation of the sun as a paradigm. This sort of thing would validate the acceleration, provide the repulsive force desired by cosmologists, invalidate dark matter, and so on. Linking into thermodynamics and gravity, well, lets just consider gravity alone and thermodynamics alone, but here they tieing into electromagnetism. That's awfully speculative, but gravitational shadowing as a principle is nearby as well, since light would be involved. Too much and too loose, so I am sorry, but I'm not going to delete. Thanks Timo for your strong response and that JCM reference. > > -- > Timo
From: Timo Nieminen on 1 Jun 2010 09:40 On Jun 1, 10:22 pm, "Tim BandTech.com" <tttppp...(a)yahoo.com> wrote: > On Jun 1, 12:24 am, Timo Nieminen <t...(a)physics.uq.edu.au> wrote: > > On Mon, 31 May 2010, Tim BandTech.com wrote: > > > On May 30, 2:58 pm, Sam Wormley <sworml...(a)gmail.com> wrote: > > > > On 5/30/10 9:31 AM, NoEinstein wrote: > > > > > Photons have ZERO mass, and exert zero force upon > > > > > âstrikingâ a reflecting surface. > > > >   Photons have zero REST mass, but have momentum of > > > >     p = hν/c = h/λ > > > >   A perfect reflector's momentum would increase by > > > >     2p = 2h/λ > > > >   for every photon. Ever heard of a solar sail? > > > I've recently done some research on the radiometer, and this math > > > analysis is definitely not what makes it tick. The sun is putting out > > > 1300 watts per square meter. If all of this energy goes into > > > mechanical energy then we'd be making turbines rather than PV cells. > > Apart from some very early claims about the Crookes radiometer (such as > > by Crookes), shown to be wrong a few years later, and their modern > > repetition, who claims that radiation pressure makes the radiometer tick? > > The Nichols radiometer is claimed by some to work in a vacuum, > including Nichols himself. Nichols and Hull (and Lebedev very shortly before them) were operating at the limits of what they could detect or measure, with the best vacuums they could manage affordably. That their results aren't terribly good shouldn't be a surprise. But it's been done again, and it doesn't have to be done in vacuum. We discussed some of these experiments in http://arxiv.org/abs/0710.0461 - the work by R. V. Jones was excellent, his 1954 measurements might well be the best pre- laser measurements of optical radiation pressure. So, whatever your doubts about Nichols' experiment, it's been repeated and amply confirmed many times (and at least some of these were by people who didn't Nichols' results were really good enough). These days, it's almost trivial. (I will be brief for the rest, since it is late. Perhaps I can give more detail or refs later.) > > 1300W per square metre means 9 micronewtons per square meter, on a > > perfect reflector. That it would take a square kilometer to be able to use > > solar radiation pressure to produce the same force as the weight of 1kg > > pretty much says why we don't do this. > > Yes, well, I'd like to understand how even this slight figure comes > about. It is easy to falsify the e=hv momentum claim (which is a big > enough statement) but even this slender acceleration is questionable > by the argument on conservation of energy. This is just the momentum of a photon p=h/lambda claim. But it isn't a quantum result; quantum mechanics just inherits this from the classical theory. The standard result in the classical theory is that the momentum flux of a parallel beam of power P is P/c (for light in free space or some medium with refractive index close enough to 1). For light in some other medium, such as water, momentum flux = nP/c. You can obtain this result via at least 3 different routes: (a) the Lorentz force, (i) by directly calculating the force for a specific case, or (ii) by obtaining the momentum flux of an elecromagnetic wave along the lines of the derivation of Poynting's theorem. (b) the Lagrangian formulation of EM theory + Noether's theorem. (c) the thermodynamics of moving energy around without moving mass around. Jackson's book, Classical electrodynamics, does (a)(ii) and (b). (c) goes back to N. A. Umov, 1874 (I haven't seen this last in English). > Why oh why would we rely upon a volume figure to assess the force on a > plate? The figuring does not extend generally either. For instance, > staying with Watts and Joules and seconds what if we consider a one > second interval of the solar power? Now rather than a 1mx1mx1m box we > have a box extending 3e8 meters toward the sun, and now the > computation gets trickier, for the assumption on this 1kJ box of > energy now has to worry about the proximity to the sun. We don't have to rely on a volume to find the force on a plate. But the density and flux of a quantity are related by the speed of transport of the quantity, so once you know the density, you know the flux. > I am not familiar with modern physics using the electokinetic energy > versus electrostatic energy. What seems most familiar is >   e = h v > where v is proportional to the frequency of a supposed photon. You > seem to have validated that photon momentum is not responsible for the > radiation pressure. Maxwell's "electrokinetic energy" isn't modern. Maxwell can be hard to read, since he is archaic. > I'm honestly not clear on whether you are in support of a mechanical > pressure or not. This does not really matter, but because the > ballistic theory of light and black body principles rest nearby, then > there is some cause for interest beyond the toy light-mill's > functionality. I believe it is accurate to translate the 1300 W/m/m of > the sun directly into photon energy. If one photon >   e = h v > is a bullet then how much force does it impart? Is Wormley correct? > Then why doesn't it translate? You see, we are knocking on the back of > the black door. I don't think we're anywhere mysterious here. Inertia of energy (which means that moving energy has momentum) goes back to Umov 1874 on thermodynamic grounds, Einstein 1905 on more general relativistic grounds, that electromagnetic energy has inertia goes back to Poynting and Heaviside in 1884. Given the energy of a photon as E=hf, then you have mometum p=h/lambda, since p=E/c. And it all works for other kinds of waves, and angular momentum too. But it used to be mysterious. Back in the early 1800s, it was argued that light was a wave phenomenon rather than a corpuscular phenomenon since radiation pressure was not observed - how could something massless like a wave exert a force? These days, with the idea that electromagnetic fields can exert forces, and light being an electromagnetic wave, optical radiation pressure is about as mysterious as an electric motor. Which is to say, that it exists and works is clear, whatever fundamental mysteries of "why" remain. It's well-tested quantitatively. It isn't too hard to verify the momentum of light to within 10% using optical tweezers (e.g., our experiment in http://arxiv.org/abs/physics/0610087 . Yes, we say better than 1%, but that's with a known particle for calibration, to find the power at the focus of our trap. Without this, we'd have a larger error, mainly in the estimate of this power. Still, no more than 10%.) > > > The most blatant farce is in terms of conservation of energy. The > > > claim is that the light hitting a reflective surface will provide > > > twice the momentum; one kick when the light hits it and one kick again > > > from the light when it leaves. This concept offends the conservation > > > of energy. 1300 watts in with 1300 watts out leaves no acceleration > > > whatsoever for the perfect reflector. > > > If the reflector is moving, there will be a Doppler shift, and energy in > > will be different from energy out. If the reflector is stationary, then > > you could have, e.g., 1300W in and 1300W out. But no work would be done.. > > Very good. We have agreement, particularly at the low velocities that > these instruments work at. As far as we can tell there is no reliance > upon red shifting of light, which could provide some work. The force doesn't depend on redshift. But it doesn't take any expenditure of energy to produce a force - just ask a fridge magnet or a paperweight. Having the force do work does very much depend on redshift, since the reflector has to move for the radiation pressure to do work on it.
From: NoEinstein on 1 Jun 2010 10:40 On May 31, 8:11 pm, BURT <macromi...(a)yahoo.com> wrote: > On May 31, 3:31 pm, NoEinstein <noeinst...(a)bellsouth.net> wrote: > > > > > > > On May 30, 2:48 pm, Timo Nieminen <t...(a)physics.uq.edu.au> wrote: > > > Dear Timo: I like that you have had a broad exposure to the world of > > physics. My New Physics is different in that it is based almost > > solely on analysis and on reason. To avoid being corrupted by the > > status quo, I relish the observations of valid experimentswhile > > always being open minded to the possibility of errors. I avoid > > automatically accepting the explanations, by supposed authorities, > > for the observed phenomena. > > > White and black squares are two competing gravity experiments > > combined into one. In the Crookes Radiometer, the black squares > > exhibit more repulsion from the light (or heat) source than the white > > squares. Reverse rotation has been observed (by others) to occur if > > the glass is made to be cooler than the vanes, themselves. You say > > The force on the vanes has been measured in vacuum, and the force is > > in the opposite direction to the usual Crookes radiometer thermal > > force. If not for friction, the radiometer in vacuum would rotate > > "backwards". That observation may or may not be a true analogy to the > > Crookes. I dont make it a point to shoehorn anyones observations > > unless and until I know most of the particulars. > > > *** I invite you to reply with a concise PARAPHRASE of how that in > > vacuum experiment was done. (Note: I do not read links to the words > > of others.) The thermal qualities of the vacuum container must be > > considered, as well as the thermal isolation of the white paint from > > the black paint, if present. Since there was no rotation, how was > > the force measured? > > > Like I have said, conclusively, massless photons, alone, exert no > > force on objects. What is actually happening to move small objects is > > that photons create a gravity effect, as explained in: > > > There is no "pull" of gravity, only the PUSH of flowing ether!http://groups.google.com/group/sci.physics/browse_thread/thread/a8c26.... > > > The latter involves having the varying ether flow and density push the > > object in proportion to the objects cross section that is in the > > photon stream. Dust particles adjacent to laser beams can be seen to > > move in the direction of the beam. But that is due to the air > > molecules, and the ether being moved, together. The dust is pushed by > > the air gases and by the flowing ether, not by the photons. > > > That Wikipedia article on Radiometers mentioned that there is an > > induced gas flow through porous ceramic plates that is toward the side > > that is heated. [ Note: That is consistent with the ether flow > > direction predicted by my New Science. ] The rather iffy porosity of > > the edges of the squares in the Crookes Radiometer has, for over a > > century, been considered to be the primary source for the thrust. The > > errant rationale has been: The edges of the black squares heat, and > > then shoot-out, the argon atoms, causing the observed rotation. The > > latter concocted science, combined with Einsteins heated gas > > nonsense, supposedly accounts for 100% of the observed rotation of the > > vanes. > > > Photons are concentrations of energy which, in high enough > > concentrations, can burn through steel. Those photons dont force > > through the steel. You could say: They energy through the steel! > > Radio waves pass through steel. > > Mitch Raemsch > > > > > Timo, Ive observed over the past month that you have, occasionally, > > been adversarial regarding aspects of my New Science. To the extent > > that you bring up valid points which I can explain to the many > > readers, I welcome your comments. But I dont seek to have a time > > consuming one-on-one conversation with you just for your edification. > > Though this reply is long, dont take that to be an invitation that > > you have been selected as the spokes-person for the status quo. > > Because of my obvious huge contributions to science, you should ask > > questions, not sit in judgment. You are welcomed to make your own > > +new post(s) to pontificate your science if you differ with me. > > Lastly, please TOP post, and limit yourself to about two paragraphs. > > I really dont need to hear what you think about every little thing > > that Ive ever said. No more PDs are wanted, here. Thanks! > > NoEinstein > > > > On May 31, 12:31 am, NoEinstein <noeinst...(a)bellsouth.net> wrote: > > > > > Ive just learned, and provisionally accept as true, that: Radiometers > > > > wont rotate at all in a perfect vacuum; > > > > True enough, but misleading, since there is still a measurable force. > > > Only the friction of the bearings stops it from rotating. > > > > > If the devices were totally > > > > frictionless, the rotation would occur in the identical direction > > > > without that gas being there. > > > > This isn't true. The force on the vanes has been measured in vacuum, > > > and the force is in the opposite direction to the usual Crookes > > > radiometer thermal force. If not for friction, the radiometer in > > > vacuum would rotate "backwards". > > > > Seehttp://en.wikipedia.org/wiki/Nichols_radiometer > > > > This reverse force due to radiation pressure was measured in 1901. > > > (Published in 1901, anyway. I think Nichols and Hull did their > > > measurement in 1901, but Lebedev did his in1899, but didn't publish in > > > a journal until 1901.) > > > > > Photons have ZERO mass, and exert zero force upon > > > > striking a reflecting surface. > > > > Non-zero force. This has been measured. Microscopic objects can be > > > easily pushed around with this force. Macroscopic objects have been > > > levitated against gravity. It's more common to use the force due to > > > refraction (which is also non-zero), since then you don't cook the > > > object being pushed, but reflection works too. (Also absorption.)- Hide quoted text - > > > - Show quoted text -- Hide quoted text - > > - Show quoted text -- Hide quoted text - > > - Show quoted text - No disagreement, there; provided the steel isn't too thick. NE
From: NoEinstein on 1 Jun 2010 10:47
On May 31, 8:44 pm, Timo Nieminen <t...(a)physics.uq.edu.au> wrote: > Dear Timo: You are being adversarial. You belittle me by claiming that giving answers is simple for 'me'. Yet, you can't find or figure out simple things for yourself. I refuse to walk-you-through your not very determined science journeys. Pick one or two issues or comments; top post a paragraph or two in your own words, and I will reply as apt. Thanks. NE > > On Mon, 31 May 2010, NoEinstein wrote: > > *** I invite you to reply with a concise PARAPHRASE of how that in > > vacuum experiment was done. (Note: I do not read links to the words > > of others.) > > Why should I bother paraphrasing such things? _You_ don't bother answering > simple direct question that should take a genius like yourself only 10 > minutes or so to answer. Does somebody of your intellect need others to > pre-digest your reading for you? Of course not! Since you're clearly > capable of reading, read: > > P.N. Lebedev > Untersuchungen über die Druckkräfte des Lichtes > Annalen der Physik 6, 433 (1901) > > E.F. Nichols and G.F. Hull > A preliminary communication on the pressure of heat and light radiation > Physical Review 13, 307 (1901) > > > Like I have said, conclusively, massless photons, alone, exert no > > force on objects. > > Simply wrong. Force due to electromagnetic waves is routinely observed. > Fundamentally, no different from the force that drive electric motors. > > And since you're already whining about your two-paragraph attention span > being exceeded, I'll stop here. |