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Natural Science Forum / Physics / Relativity / June 2005Speed of light in medium constant?
Hi again, Is speed of light traveling in a medium constant for all observers? Thanks. (I think, space contraction would render the density of the medium higher, so it might seem slower. On the other hand, this might not look consistent when we compare it to a light traveling in vacuum..) w...@operamail.com Jun 21, 2:07 pm show options Newsgroups: sci.physics.relativity From: w...@operamail.com - Find messages by this author Date: 21 Jun 2005 11:07:36 -0700 Local: Tues,Jun 21 2005 2:07 pm Subject: Speed of light in medium constant? Reply | Reply to Author | Forward | Print | Individual Message | Show original | Report Abuse Hi again, w...@operamail.com asks: Is speed of light traveling in a medium constant for all observers? Suppose you were passing the light through the ocean, water being a suitable medium. One observer travels toward the source in a rowboat at one meter/second, another in a powerboat at 100 meters/second. Both boats are the same length. The experiment starts when the bow (that's the sharp end) of each boat is side by side. Does the light reach the stern (that's the blunt end) of the powerboat before it reaches the stern of the rowboat? If it does, then each observer must calculate a different speed of light, being (length of boat)/time. If you want to do the same experiment in a vacuum, take the water away. AD. > w...@operamail.com asks: > [quoted text clipped - 12 lines] > a different speed > of light, being (length of boat)/time. Intuitively I would say it does, but that would be not taking relativity effects into account.. > If you want to do the same experiment in a vacuum, take the water away. I think that would make a difference, since vacuum does not have a relative speed wrt the observers, while water does.. > AD. Thanks. w...@operamail.com wrote: I think that would make a difference, since vacuum does not have a relative speed wrt the observers, while water does.. Good answer, but surely the source of light has a relative speed wrt the observers? As for a "relativistic" effect, let's look at what that might be. Using our boat length as a yardstick, we'll stop the rowboat from moving toward the source and move the speedboat even faster. Let's say the light hits the bow of each boat at t = 0, tau = 0. Now, Einstein builds his theory on a definition. He says the "time" for light to travel from A (the bow of the boat) to B ( the stern of the boat) is equal to the "time" it takes to travel from B back to A, so we'll need a mirror in the stern to reflect the light. He also says the speed of light in empty space has a definite speed c and is independent of the motion of the source, so that would indicate that the speed of the mirror has no effect on the speed of the light, except to change its direction, of course. He doesn't tell us which mirror the boat is in, but we'll assume we are allowed to install a mirror in the moving boat. Now, let us say that the light hits the mirror at t = 1, reflects and hits the bow again, going the other way, at t = 2, ok? Since the light hit both bows at t = 0, and the stern of the moving boat is moving toward the light source, the stern of the moving boat must already be past the stern of the stationary boat at t = 1, and the bow of the moving boat must already be past the bow of the stationary boat when the reflected light reaches it. Since Einstein claims the speed of light is constant in the vacuum, does it take more time to reach the bow of the moving boat coming from the stern as it did to travel from the bow to the stern, less time or the same time? What he actually does is say that it travels the length of the moving boat at speed c+v, as seen by an observer in the stationary boat, and back to the bow at speed c-v. He then calculates these times as the length of the boat divided by the speed, adds them together, creates a function tau() and takes half of that, then says half the time to go from the bow to the stern and back again is the time it takes to go from the stern to the bow. Out of that are born the Lorentz equations you've heard of. Unfortunately he contradicts, by doing so, his own definition that it takes the same time each way. If the velocity of the boat is c, then the light hits the stern at t = 0.5, reflects and can never reach the bow. That would spoil everything, so he says the boat cannot travel any faster than c. Of course he didn't actually perform any experiment to verify his idea, he simply sat down and thought it up. That might be quite clever, but it isn't science. Oh, and he also says it is impossible to define time in any other way, just in case you want to define tA = tB as Newton did. AD. w...@operamail.com Jun 21, 2:07 pm show options Newsgroups: sci.physics.relativity From: w...@operamail.com - Find messages by this author Date: 21 Jun 2005 11:07:36 -0700 Local: Tues,Jun 21 2005 2:07 pm Subject: Speed of light in medium constant? Reply | Reply to Author | Forward | Print | Individual Message | Show original | Report Abuse Hi again, w...@operamail.com asks: Is speed of light traveling in a medium constant for all observers? Suppose you were passing the light through the ocean, water being a suitable medium. One observer travels toward the source in a rowboat at one meter/second, another in a powerboat at 100 meters/second. Both boats are the same length. The experiment starts when the bow (that's the sharp end) of each boat is side by side. Does the light reach the stern (that's the blunt end) of the powerboat before it reaches the stern of the rowboat? If it does, then each observer must calculate a different speed of light, being (length of boat)/time. If you want to do the same experiment in a vacuum, take the water away. AD. > Is speed of light traveling in a medium constant for all observers? In classical electrodynamics, the speed of light in a medium is c/n RELATIVE TO THE MEDIUM (n is the index of refraction of the medium). For an observer to whom the medium is moving, use the Lorentz composition of velocities. This is consistent with all experimental measurements of this. Tom Roberts tjroberts@lucent.com >> Is speed of light traveling in a medium constant for all observers? > [quoted text clipped - 4 lines] > > Tom Roberts tjroberts@lucent.com Tom: I will run the gauntlet on this: What happens to the speed of light within the medium if the observer sees the medium at the speed of light? Richard Saam I don't think the gauntlet can hurt you :-) As Tom says, "For an observer to whom the medium is moving, use the Lorentz composition of velocities. This is consistent with all experimental measurements of this." So if the wind happens to be blowing past you, or you happen to be swimming, well, just use the Lorentz composition (whatever that is, I think it was Einstein that said c = (c+v)/(1+v/c) ). Anyway, Tom should know, he's a authority on the matter. A.D. > I don't think the gauntlet can hurt you :-) > As Tom says, "For an observer to whom the medium is moving, use the [quoted text clipped - 7 lines] > he's a authority on the matter. > A.D. Until Tom answers with the objective truth here are some thoughts: O: observer A: frame A (particles in medium) B: frame B (medium) By Lorentz decomposition, I assume velocity addition in different frames such that: vOB = (VOA - vBA) / (1 - vBA vOA / c^2) so now the medium "B" is blowing by you "O" at c so: c = (c - vBA) / (1 - vBA c / c^2) c = (c - vBA) / (1 - vBA/ c) c = (c - vBA) c / (c - vBA) c = c vBA (the v difference between particles in the medium and the medium would appear to be indeterminate. Of course the medium "B" traveling at the speed of light could not have mass. I guess it would have to be composed of photons. Could particles "A" in the medium perhaps traveling at velocity relative to "B" much less than c have mass? Richard Saam Richard wrote: Could particles "A" in the medium perhaps traveling at velocity relative to "B" much less than c have mass? Beats me, Richard. I never could figure out how I could move from zero toward one light source situated at +x, move away from another at -x, and the speed of light from both of them is still c in my inertial reference of spectacle frames. Einstein's definition of time (upon which he bases his Lorentz transformations) says the "time" for light to travel from A to B is the same as the "time" it takes to travel from B to A, and he says it is impossible to define time in any other way. I think he was nuts, I've only got one watch, but what do I know? Brilliant geniuses like Tommy Roberts believe him, so that means they must be right, I suppose. They think they are, anyway, but opinions are subjective. I expect Tommy will use some capital letters to reinforce his beliefs if he bothers to answer at all. He doesn't really like being challenged with simple algebra, though, he thinks he's a physicist, and physics is SCIENCE. You are supposed to believe what he believes, not question it. Egads, you don't question a priest, do ya? It's not good form, old chap. Just not cricket. :-) Arthur. > Richard wrote: > [quoted text clipped - 7 lines] > and the speed of light from both of them is still c in my inertial > reference of spectacle frames. It is because your specticle frames and the glass enclosed within is part of the coupling structure to your retna. Each charge in the glass has some "say so" about the ratio of E and H components and the spatial position of the *loops* (as opposed to nodes) Well... they move the nodes too. LOL http://www.conformity.com/0102reflectionsfig3.gif http://www.conformity.com/0102reflections.html But posting the same URL expecting different results is surely a sign of insanity. :o) Insane Sue... > Einstein's definition of time (upon which he bases his Lorentz > transformations) says the "time" for light to travel from A to B is [quoted text clipped - 12 lines] > > Arthur. > It is because your specticle frames and the glass enclosed within > is part of the coupling structure to your retna. Each charge in the > glass has some "say so" about the ratio of E and H components > and the spatial position of the *loops* (as opposed to nodes) > Insane Sue... The spatial position of my loupe is most effective when I hold it close to my eye, but that means it is not opposed to my no_es as well. Arthur. > What happens to the speed of light within the medium if the observer > sees the medium at the speed of light? If by the last you mean c (speed of light in vacuum), then this is a situation that cannot occur. But consider the related question: What does a light wave in a medium look like to an observer moving at the speed of light in the medium (in the same direction)? It is clear that the lightwave will appear static (i.e. unchanging) to such an observer. But it will have finite wavelength (assuming the observer has comoving assistants lined up along their direction of motion who can report back the observed phase of the lightwave). Of course it will not be light to the observer, it will be static E and B fields (this is classical electrodynamics). Assume the source is at rest in the medium rest frame with frequency f: Medium Moving Observer Frame Frame ------ -------- Speed: c/n 0 Frequency: f 0 Wavelength: c/(n*f) gamma*c/(n*f) The moving observer measures the wavelength by the distance between successive peaks in the E or B fields of the "wave". So much for Mitch's repeated nonsense about "infinite redshift" being the "end of GR" -- here's a case where it is sensible, achievable, and absolutely required for the consistency of classical electrodynamics. Infinite redshift alone is not enough to indicate a problem.... Note that the observer could move with speed between c/n and c -- in this case the lightwave will be moving backwards to the observer, and if it turned on sometime in the past she could overtake its leading edge and watch it disappear. Exercise for the reader: compute the speed the moving observer must have (relative to the medium) for the wave to be going backward but have the same frequency f as in the medium frame. How does this depend on n? What are the speed and wavelength of the wave in this moving frame? Hint: answer these last questions first, and think about how the Lorentz composition of velocities applies. Tom Roberts tjroberts@lucent.com > > What happens to the speed of light within the medium if the observer > > sees the medium at the speed of light? [quoted text clipped - 16 lines] > > Tom Roberts tjroberts@lucent.com Interesting. I assume the E and B fields could exert force on a charged particle and alter its path. Does this occur in a medium only or in vacuum too? Anyway, could this not be a way to detect light without the quantum collapse (I know this group is relativity but..) > > > What happens to the speed of light within the medium if the observer > > > sees the medium at the speed of light? [quoted text clipped - 21 lines] > vacuum too? Anyway, could this not be a way to detect light without the > quantum collapse (I know this group is relativity but..) quantum collapse ??? << The system that we have developed to access this realm consists of an atom strongly coupled to a single mode of a high finesse optical cavity (mirror reflectivity R = 0.9999984), for which a single atom can profoundly effect the cavity characteristics and the field associated with less than a single photon can saturate the atomic response. >> http://www.cco.caltech.edu/~qoptics/cqed.html Sue... >>>>What happens to the speed of light within the medium if the observer >>>>sees the medium at the speed of light? [quoted text clipped - 21 lines] >>vacuum too? Anyway, could this not be a way to detect light without the >>quantum collapse (I know this group is relativity but..) I assume that such static E and B fields would occur in a standing wave situation. Do the resulting forces provide the mechanism for atomic entrapment? > quantum collapse ??? > << The system that we have developed to access this realm consists [quoted text clipped - 6 lines] > > Sue... Sue One large question??: In an optical cavity with standing waves I would assume static E and B fields generating nodal energy densities E^2 and B^2 (energy/volume). Question: Can these energy densities be engineered to a magnitude large enough to create virtual particles? Richard Saam Question: Can these energy densities be engineered to a magnitude large enough to create virtual particles? I should hope not. If increasing mass or energy changes the form, would it not be changing virual particles to real particles. You are perhaps inquirng about the theoretical "conjuring" of and e+ e- pair in the absence of any other matter. I seem to recall that one of the accelerator labs is engaged in such a project, but so far, with no sucess. Refrigerator sized positron factories are now commonplace in medical imaging centers but whittle matter down as opposed to conjuring it up. Excuse my witch slang. ;-) Sue... > Question: Can these energy densities be engineered to > a magnitude large enough to create virtual particles? [quoted text clipped - 7 lines] > seem to recall that one of the accelerator labs is engaged > in such a project, but so far, with no sucess. I would certainly like to see the experimental set up for that effort. It must be a Fermi Lab or perhaps CERN Richard Saam > > Question: Can these energy densities be engineered to > > a magnitude large enough to create virtual particles? [quoted text clipped - 12 lines] > > Richard Saam Try: http://www.desy.de/~telnov/ggtesla/ That's more than I want to know... today anyway :o) Sue... > >>>>What happens to the speed of light within the medium if the observer > >>>>sees the medium at the speed of light? [quoted text clipped - 43 lines] > In an optical cavity with standing waves > I would assume static E and B fields Whoa, steady on! First we have to decide what is meant by a standing wave. Tommy's version is that of a surf rider, remaining at the crest of the wave as he moves toward the beach. In the frame of the surf rider he experiences no frequency, his height doesn't change. However, a CLASSICAL standing wave isn't like that at all. Although it has no velocity, it retains both freqency and wavelength, and has nodes where no amp[itude takes place. Ampitude at t = 0: \ /\ / \ / \ / \ / \ / \ / \ / \/ \/ at t= 0.25 the amplitude is reduced. __ ____ __ \ / \ / ---- ---- zero amplitude at = 0.5: ___________________ reversal at t= 0.75 ___ ___ / \ / \ -- --- -- at t = 1: /\ /\ / \ / \ / \ / \ / \ / \ / \/ \ The crests have not moved to the right or the left, so the standing wave has no velocity. It still has frequency and wavelength. > generating nodal energy densities E^2 and B^2 > (energy/volume). [quoted text clipped - 3 lines] > > Richard Saam I don't know what a "virtual" particle is, or what you mean by it. When you pass a current through a rod, a magnetic field takes place in the vicinity of the rod and is detected at some distance d from the rod. There is a small but finite time delay between the moment the current commences and the moment the magnetic field is detected at d, and the further away the detector, the greater the time delay. If the current is reversed before the detector has noticed the initial current, then we must have an electromagnetic wave. Curiously, we can place a reflector on the other side of the rod from the detector that causes the intensity of the magnetic field at d to increase, thus beaming the energy in one direction only and skirting around the inverse square law. When we reflect the energy into a beam in this manner, we call the resultant wave a photon stream. I don't call them virtual, light beams are quite real. So to answer your question, yes. We call it radio. I only disagree that the "particles" are "virtual". To emit a pulse in all directions, turn the current in the rod on and off again, once. To emit one photon, direct the wave with a reflector and turn the current on and off again, once. That should solve the wave/particle duality question. Arthur Dent. >>>>>>What happens to the speed of light within the medium if the observer >>>>>>sees the medium at the speed of light? [quoted text clipped - 97 lines] > > I don't know what a "virtual" particle is, or what you mean by it. I meant the e+ e- as Sue was refering to > When you pass a current through a rod, a magnetic field takes place in > the vicinity of the rod and is detected at some distance d from the [quoted text clipped - 16 lines] > wave/particle duality question. > Arthur Dent. Can you modify your graphics in terms of a standing wave composed of opposing rectified waves? Ampitude at t = 0: \ /\ / \ / \ / ---\----/----\----/ at t= 0.25 the amplitude is reduced. \ /\ / \ / \ / ---\----/----\----/ zero amplitude at = 0.5: \ /\ / \ / \ / ---\----/----\----/ reversal at t= 0.75 \ /\ / \ / \ / ---\----/----\----/ at t = 1: \ /\ / \ / \ / ---\----/----\----/ The crests have not moved to the right or the left, so the standing wave has no velocity. It still has wavelength but no frequency. Richard Saam > >>>>>>What happens to the speed of light within the medium if the observer > >>>>>>sees the medium at the speed of light? [quoted text clipped - 121 lines] > Can you modify your graphics in terms of a standing > wave composed of opposing rectified waves? I didn't catch on right away, but it looks as if you are employing a halfwave (single diode) rectifier and not a fullwave bridge rectifier. Actually, a standing wave of the type I described can also be considered as the superposition of two identical waves travelling in opposite directions. This is quite easy set up in a long tank of water, the right going wave reflecting at the ends of the tank. When we rectify an AC current we get a DC current, of course, so the current, although varying with time, is always above the line and always positive. If you attempted what you suggest, you'd have zero current as far as I can see. > Ampitude at t = 0: > > \ /\ / > \ / \ / > ---\----/----\----/ Ok, that is the positive half of the wave. The negative half would be ----\----/----\----/----time - > \ / \ / \/ \/ For full wave rectification, we have \ /\ /\ /\ / \ / \ / \ / \ / ---o----o----o----o--- time -> where the negative half is flipped and added to the top half. A bridge rectifier will do this. However, we wouldn't call that a standing wave,we'd call it a constant current. Part of the problem here isn't just the limitation of poor graphics capability, it is the inherent confusion between using the horizontal axis as a measure of time and also as a measure of distance. As time progresses to the right, the height of the crest varies. In the case of the standing wave, the height varies as a function of time also, but doesn't change position. What I tried to draw was the time axis vertical as a series of snapshots of the wave, with the position of the crests/troughs shown horizontally. In the rectified wave above, the horizontal axis is time, not position. A.D. > >>Question: Can these energy densities be engineered to > >>a magnitude large enough to create virtual particles? [quoted text clipped - 3 lines] > > I don't know what a "virtual" particle is, or what you mean by it. > I meant the e+ e- as Sue was refering to Virtual particles are mathematical abstractions or placeholders used in Feynman diagrams. They are not much use in understanding the mechanisme of standing waves. Usually if you remember that there are no magnetic monopoles and no single terminal ammeters you can figure out where and why they stand as they stand. ;o) Sue... >>>>Question: Can these energy densities be engineered to >>>>a magnitude large enough to create virtual particles? [quoted text clipped - 12 lines] > > Sue... Sue Given the Heisenberg Uncertainty delta_p delta_x => hb/2 and delta_E delta_t => hb/2 Now define a lattice condition (standing optical waves in a vacuum) such that latticed geometry satisfies following condition: delta_p delta_x = delta_E delta_t => h/2 where: delta_p = delta_m delta_v delta_E = delta_m(delta_v)^2/2 delta_t = delta_x/delta_v hb = h/(2*pi) Do virtual particles arise or conjure to satisfy this very well defined geometrical symmetrical situation (maybe as per Madam Emmy Noether). Richard Saam > >>>>Question: Can these energy densities be engineered to > >>>>a magnitude large enough to create virtual particles? [quoted text clipped - 42 lines] > > Richard Saam They might do that in Hilbert Space but that is no place to model propagation. <<There is in particular one problem whose exhaustive solution could provide considerable elucidation. What becomes of the energy of a photon after complete emission? Does it spread out in all directions with further propagation in the sense of Huygens' wave theory, so constantly taking up more space, in boundless progressive attenuation? Or does it fly out like a projectile in one direction in the sense of Newton's emanation theory? In the first case, the quantum would no longer be in the position to concentrate energy upon a single point in space in such a way as to release an electron from its atomic bond, and in the second case, the main triumph of the Maxwell theory - the continuity between the static and the dynamic fields and, with it, the complete understanding we have enjoyed, until now, of the fully investigated interference phenomena - would have to be sacrificed, both being very unhappy consequences for today's theoreticians.>> Max Planck - Nobel Lecture Nobel Lecture, June 2, 1920 http://nobelprize.org/physics/laureates/1918/planck-lecture.html Sue... >>>>>>Question: Can these energy densities be engineered to >>>>>>a magnitude large enough to create virtual particles? [quoted text clipped - 64 lines] > http://nobelprize.org/physics/laureates/1918/planck-lecture.html > Sue... Sue: very interesting comment. "Does it spread out in all directions" Or "does it fly out like a projectile in one direction" Now refering to Auther Denton's previous graphic full wave rectification, we have \ /\ /\ /\ / \ / \ / \ / \ / ---o----o----o----o--- time -> From computer graphical optical interference patterns, The standing wave rectified peaks must stay stationary in space and time for required symmetry with Heisenberg "virtual" particle generation approach above. Its like the pendulum swings to its amplitude and stays there. All potential and no kinetic energy. How do you produce this symmetry optically in the real world, I do not know. Is there a way? Does this stand in the middle of your comments?: "Does it spread out in all directions" Or "does it fly out like a projectile in one direction" I look forward to reading Max Planck speaking to us over the years. Richard Saam > >>>>>>Question: Can these energy densities be engineered to > >>>>>>a magnitude large enough to create virtual particles? [quoted text clipped - 72 lines] > > Now refering to Auther Denton's previous graphic > >> > full wave rectification, we have [quoted text clipped - 16 lines] > in the real world, I do not know. > Is there a way? Of course. But you can expect little sucess on a high playground swing without either a playmate to push you or some knowledge of parametric frequency conversion. I can't for the life of me figure out how even pre-schoolers get throught all the maths, but their performance on the playground is ample evidence they have it mastered. << This takes an input signal at a frequency and multiplies with another signal at a frequency to produce an output at either the sum or difference frequencies; >> http://www.cooper.edu/engineering/projects/gateway/ee/solidmat/modlec3/node7.html > Does this stand in the middle of your comments?: > > "Does it spread out in all directions" > Or > "does it fly out like a projectile in one direction" It explores all paths. http://www.physics.yorku.ca/undergrad_programme/highsch/Feynm4.html Sue... > I look forward to reading Max Planck speaking to us > over the years. > > Richard Saam >>How do you produce this symmetry optically >>in the real world, I do not know. [quoted text clipped - 23 lines] > > Sue... Thank you for the direction. I am still at the kindergarden stage. Went out to play. All of those swings and toy things are great. The best that I can do at this stage is: http://arxiv.org/abs/physics/9905007 Looking for a push by anyone concerned. Looking at equality of reciprical lattices as an insight. Richard Saam > >>How do you produce this symmetry optically > >>in the real world, I do not know. [quoted text clipped - 37 lines] > > Richard Saam All those cosmological equations surely have some effect on the exact moment you shorten the length of swing's chain to get the maximum boost on each cycle. Unless you noticed some real descrepancy at the playground, I would not loose too much sleep over it. :o) Sue... >>>>How do you produce this symmetry optically >>>>in the real world, I do not know. [quoted text clipped - 45 lines] > > Sue... Sue Not much sleep lost over it, but just wondering if it all could be scaled to some laboratory dimension of scientific curiosity or engineering use as per: Optically create adjacently non parallel constant potential surfaces bounding chiral cells that focus Feynman's arrows into orthogonal paths congruent with conjured elastic particle/charge travel. When executed, what do you think the chances of finding something interesting or even useful? Richard Saam > >>>>How do you produce this symmetry optically > >>>>in the real world, I do not know. [quoted text clipped - 61 lines] > > Richard Saam Cosmic structure and cooper pairs are way beyond any of my experience but some of your relations with trisine geometry are interesting. In another thread we are toying with some quantum gravity. Our modeling *feels* like it is getting too squisshy too fast as we try to extrapolate from Maxwell's equations up to London forces. Have you tried trisine geometry to model induced dipole effects? If it could be used that way the results might be much clearer than quantum or tensor descriptions. Sue... http://citebase.eprints.org/cgi-bin/citations?id=oai:arXiv.org:astro-ph/0501626 >>>>>>How do you produce this symmetry optically >>>>>>in the real world, I do not know. [quoted text clipped - 65 lines] > of my experience but some of your relations with > trisine geometry are interesting. In another thread where? > we are toying with some quantum gravity. Look at equation 2.14.7 for some possible insight. Our > modeling *feels* like it is getting too squisshy > too fast as we try to extrapolate from Maxwell's > equations up to London forces. Have you tried > trisine geometry to model induced dipole effects? kTc = Madelung*(3/2)*e*e/(epsilon*(2*B/SQRT(3))) = hb^2 kB^2 / (2 mt) = mt vdx^2/2 epsilon = displacement field / electric field = D/E = 6.16E+10 D and E are integral to trisine lattice Madelung is the conventional infinite series for trisine lattice seems to work within 3% at all "B". > If it could be used that way the results might > be much clearer than quantum or tensor descriptions. > > Sue... > > http://citebase.eprints.org/cgi-bin/citations?id=oai:arXiv.org:astro-ph/0501626 This reference model assumes drag equation: F = M a = -Area rho v2 This may not be appropriate. Deceleration 'a' is not a function of v (~ 25,000 mph dr/dt for Pioneer) implying: F = M a = -Area rho c2 with rho very small ~6E-30 g/cc to fit NASA JPL data. Look at reference: How does the cosmological constant fit into general relativity? http://super.colorado.edu/~michaele/Lambda/gr.html "Because the cosmological constant term is proportional to the metric, the pressure associated with the vacuum is then given by the relation": pressure = -rho c2 = -mc2/volume "So the cosmological constant behaves gravitationally like matter and energy except that it has negative pressure. The net effect of a positive cosmological constant is then to create a repulsive gravitational force. This repulsion acts to expand the universe." It would appear that the model: F = M a = -Area rho c2 M = Pioneer mass g Area = Pioneer cross section cm2 rho = space vacuum density ~ 6E-30 g/cc c = speed of light cm/sec is a direct measurement of the vacuum density by Pioneer Space Craft. Richard Saam > >>>>>>How do you produce this symmetry optically > >>>>>>in the real world, I do not know. [quoted text clipped - 89 lines] > > seems to work within 3% at all "B". Thank you. I note your table 2.6.2 has a comparison of London penetration. If we get more involved in the persuit that might be an interesting tool or benchmark. Sue... > > If it could be used that way the results might > > be much clearer than quantum or tensor descriptions. [quoted text clipped - 51 lines] > > Richard Saam > >>>>>>How do you produce this symmetry optically > >>>>>>in the real world, I do not know. [quoted text clipped - 116 lines] > > http://super.colorado.edu/~michaele/Lambda/gr.html While I can't put a lot of rigor to this, the derivation for expansion pressure appears generally to agree with the principles described in: "Electromagnetic momentum" http://farside.ph.utexas.edu/teaching/em1/lectures/node63.html So... unless a sign, decimal place, or a one dropped on the floor, it can't be too far off the mark. :o) Sue... > "Because the cosmological constant term is proportional > to the metric, the pressure associated with the vacuum [quoted text clipped - 24 lines] > > Richard Saam >>>>>>>>How do you produce this symmetry optically >>>>>>>>in the real world, I do not know. [quoted text clipped - 130 lines] > > Sue... Yes E^2 = energy/volume = pressure but what E? Reference: Study of the Pioneer Anomaly: A Problem Set Slava G. Turyshev, Michael Martin Nieto, and John D. Anderson (Dated: February 24, 2005) http://xxx.lanl.gov/abs/physics/0502123 TABLE IV: Error Budget: A Summary of Biases and Uncertainties Solar radiation pressure at many AU: .03 (+/- .01) x 10^-8 cm/sec^2 is insignificant to observed deceleration of: 8.74 (+/- 1.33) x 10^-8 cm/sec^2 Actual pressure on Pioneer space craft in more in line with vacuum energy rho c^2 where rho = ~6 x 10^-30 g/cm^2 corresponding to estimate of dark energy_matter density Richard Saam >>"Because the cosmological constant term is proportional >>to the metric, the pressure associated with the vacuum [quoted text clipped - 24 lines] >> >>Richard Saam >>>> How do you produce this symmetry optically >>>> in the real world, I do not know. [quoted text clipped - 9 lines] >>> >>> << This takes an input signal at a frequency and multiplies >>> with another signal at a frequency to produce an output at >>> either the sum or difference frequencies; >> http://www.cooper.edu/engineering/projects/gateway/ee/solidmat/modlec3/node7.html >>>> Does this stand in the middle of your comments?: >>>> [quoted text clipped - 3 lines] >>> >>> It explores all paths. http://www.physics.yorku.ca/undergrad_programme/highsch/Feynm4.html >>> Sue... >> [quoted text clipped - 19 lines] > > Sue... Sue Not much sleep lost over it, All appears to be well in the cosmos but just wondering if it all could be scaled to a Heisenberg laboratory dimension of scientific curiosity or engineering use as per: Optically create adjacently non parallel constant potential surfaces bounding chiral cells that focus Feynman's arrows into orthogonal paths congruent with conjured elastic particle/charge travel at Heisenberg Uncertainty. When executed, what do you think the chances of finding something interesting or even useful? Richard Saam > > > What happens to the speed of light within the medium if the observer > > > sees the medium at the speed of light? [quoted text clipped - 20 lines] > particle and alter its path. Does this occur in a medium only or in > vacuum too? Moving charged particles with electric and magnetic fields in a vacuum is the principle upon which TV tubes operate, and unless you have a flat screen monitor for your computer, is taking place two feet in front of you as read this. > Anyway, could this not be a way to detect light without the > quantum collapse (I know this group is relativity but..) As Tommy says, to an observer moving with the wave it would appear as a static (i.e. DC) E-field and/or B-field. DC Magnetic fields do have the property of moving not just charges, but complete engine blocks in junk yards. An alternating magnetic field will move charges up and down an antenna, producing an alternating voltage as the charges gather alternately at the ends of the antenna. The bone of contention between Sue and I is her insistence that the magnetic field doesn't exist unless the charges are moving to produce it, and I say the charges move because the magnetic field causes them to. In reality, of course, she's be correct at the transmitter and I'd be correct at the receiver, but don't tell Sue that, or she'll need to change her hat size. Oh, and the voltage doesn't exist unless the charges are gathered at the pole (chuckle). Anyway, having decided what goes on at the transmitter and the receiver, we now enquire what is taking place in between, and recall that flashlights have curved reflectors, TV antennae have curved reflectors or yagi, both are highly directional, so what do YOU think is happening halfway between the satellite and your TV? Arthur Dent. > > > > What happens to the speed of light within the medium if the observer > > > > sees the medium at the speed of light? [quoted text clipped - 42 lines] > correct at the receiver, but don't tell Sue that, or she'll need to > change her hat size. Eh! !!! My stylist plans for sucess not failure. http://www.hair-styles.org/imageJFT.JPG The stylist wants to know if the charged comb in a shaky hand when coupled to a vibrating cotton ball is considered the transmitter or the receiver. This is vitally important to their enterprise because the whole fee structure is based on who gives and receives service. Also... If the comb is the receiver do you think she should file for bankruptcy before her patrons find it out? Sue... Oh, and the voltage doesn't exist unless the > charges are gathered at the pole (chuckle). > [quoted text clipped - 6 lines] > > Arthur Dent. > > > > > What happens to the speed of light within the medium if the observer > > > > > sees the medium at the speed of light? [quoted text clipped - 60 lines] > > Sue... Ask for a discount on your hairdo for the electrons your sylist has pinched from your hair, or demand them back. They are your electrons. A.D. > Oh, and the voltage doesn't exist unless the > > charges are gathered at the pole (chuckle). [quoted text clipped - 7 lines] > > > > Arthur Dent. >> What does a light wave in a medium look like to an observer >> moving at the speed of light in the medium (in the same [quoted text clipped - 9 lines] > Interesting. I assume the E and B fields could exert force on a charged > particle and alter its path. Sure. > Does this occur in a medium only or in > vacuum too? Both. > Anyway, could this not be a way to detect light without the > quantum collapse (I know this group is relativity but..) I explicitly said this is classical electrodynamics, so there is no "quantum collapse". Note that "quantum collapse" is an artefact of only certain interpretations of quantum mechanics, and to many physicists it seems artificial and unwarranted. Other interpretations avoid it. IMHO the best way of seeing this is to realize that any measurement of a quantum object by a macroscopic detector involves an interaction between object and detector -- basically the enormous detector becomes correlated with the quantum object (else it is not measuring the object), and its enormous size imposes a correlation back on the object that forces the object's state to be an eigenstate of the relevant parts of the detector. Tom Roberts tjroberts@lucent.com |
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