Sorry Vern - carry on. And thanks to others who helped me correct my view. I do remember that the Poynting vector is ExB and that sin & cos are orthognal when integrated over 2 pi so if I were correct, then light and EM waves in general could not transport energy. Some where in the last fourty or so years the idea that the collapsing B field generated the rising E field displaced the correct view in my head. again thanks for correcting me.
Billy T; I value your comments; if you had been correct you would have convinced me. Now that you need not stop at the first photon schematic, you might try having another look at how to get gravity out of Lorentz's treatment of Maxwell's fields.
I actually had the same idea at one point and spent some time tracking it down, why I had that mixed up in my mind. In my case I think the culprit was my first circuits course. Capacitors store energy in an electric field and inductors store energy in a magnetic field. So if you have an LC oscillator you have the magnetic field in the inductor 90º out of phase with the electric field in the capacitor. I am pretty sure that is where I got the idea mixed up, but in an introductory circuit course the LC circuit does not radiate EM energy significantly at all. -Dale
LC circuits had me confused on this point in very much the same way. I finally got my head around the idea that what a varying magnetic field does is not to directly generate an E field at that point but to "wrap" an E field _around_ that point. And vice versa the B field around dE/dt.
Thanks again to all. I really feel dumb as even when I was remembering wrongly E =-dB/dt I was aware of Gauss's law the divergent of E at a point is the charge density at that point, so I should have realized, even if memory was failing and I was confused as others have been about how changing B fields make E ,I should have known: Del dot E = rho - dB/dt I hope that is now a correct statement of one (the only one I remember) of Maxwell's laws. There is one about the curl of B, I think, but I can't dredge it up any more, but surely it at least relates B to the current producing B.
It's my understanding that matter and energy are just concentrated forms of space, this seems to fit in with the notion of an ether.
Yes, I owe you that now (after falsely sending you off into the internet jungle.). But the math of physic was never my strong point, so may not be able to help (or hurt) much. Near your second drawing, which I do not understand except for the main EM wave/photon, especially the little blue blobs that make curved chains, I found text: "...when a point in space begins to change its electric and magnetic state to accommodate a passing photon, it does not reset to zero, but modifies its present state." Are you saying than once a photon has gone past point (x,y,z) that point is forever changed? (not "reset") Or just that there is some sort of shift while the photon is near a point, in fact at all points in universe with inverse r^2 diminishing effect? If the latter, are not all points changing all the time, at least very slightly? I.e. except for the much greater magnitude of the effect is there any thing special about the closest photon to (x,y,z)? In next block of text you conclude with the statement that all photons attract each other. I have my doubts about this. Certainly, in the conventional universe, photons inter act with gravity fields and their "straight trajectory" seem to be curved, but in some minimum action or GRT view is still "straight" (Some people don't do windows -I don't do GR, Please Register or Log in to view the hidden image! so I do not know much about this - just "spouting words.") About half a year ago, here at sciForums I formulated for my own use as simple rule (may not be correct) a to when the mass, m, associated with energy via E = mC^2 did "make gravity." Physics Monkey and some others much better informed did not like my rule and thought only via GR could one be sure etc, but it seemed to work. It was: If the energy is "frame invariant" - i.e. all frames agree the quanitity of energy is the same, then that energy does make gravity. For example thermal energy does make gravity and the kinetic energy of a flying bullet does not add any gravity to the rest mass gravity of the bullet. If my simple non GR rule is correct (a big IF) then photons do not* make gravity but they do respond to gravity from other sources. (I like to say they have “relativistic mass” but that infuriates more modern physicists.) That rule is the origin of my doubt about your statement concerning photons attracting each other. I am not sure of what the current well-versed physicist thinks. Why do you believe they do attract each other? Just by way of encouragement, I have always found it interesting that (1) electrostatic and gravity fields are the same inverse square fall off form their sources. and (2) why exactly 2.000000..., instead of 2.0367 etc for the power? I am well aware that if it were not exactly 2, there would be very serious consequences, not quite as sure that both must be the same, but perhaps only the anthropomorphic principle makes the power 2 - i.e. I doubt, but do not know, if we could exist it were different. It is not as obvious as fact that we could not exist if water were densest at 0 instead of a warmer point. (Oceans always frozen from the bottom up etc.) ----------------------------- *In some frames they are blue, but in others red with less energy.
Actually that should be "Del cross E" but I think you probably know that and it was a typo. Anyway, the curl of E is proportional to dB/dt and the curl of B to dE/dt. Appropriate constants and signs sprinkled in of course. Please Register or Log in to view the hidden image!
Fix broken link. Hi Billy T; thanks looking at my gravity attempt again. No; I'm just trying to show how the state of constantly changing photon flux can add to the changing fields of a passing photon and so cause it's central point to be offset toward increasing field strength of the photon flux. That would make the photon respond gravitatially. Gravity would actually be the photon flux. I think the current state of thinking in the standard model is that photons do attract each other gravitationally and respond to gravity as well; hence black holes etc. Photon Flux: The electric and magnetic fields surrounding a photon and extending outward forever, spreading at the speed of light. They are too weak to detect normally because they follow the inverse square rule diminishing with distance. This would be what is called the Virtual Photon field by the QM faithful.
I'm not sure I understand; is something missing ? I suspect that both sides of the mass energy equaiton "make gravity" whether it is in the energy state or the mass state. So if that is what you are saying; seems right to me.
I did not bring any of my physics books to Brazil, but is not Gauss's law: Divergence of E = rho ? (perhaps some factor to get the units correct) I.e I may be wrong again, but can not claim it was just a typo.
I am going to need some more precise definitions as I do not think I understand especially as I am trying not to assume what I already know. lets start with "photon flux" and then "central point" which I think is harder to define. Is "photon flux" more related to the number of photons in a beam of one square cm or the energy in the beam? Frankly, I was thinking in terms of one photon that is passin near (x,y,z) and many others much more distant. In this concept what is "photon flux"? I also have a lot of dificulty with the the concept of "central point." For example, if you set up a two path interferomenter with paths of unequal length and are using a modest pressure gas discharge lamp, certainly if a low pressure one, the lines are reasonably "sharp" - i.e. very well defined frequencies. (Use colored glass filters to eliminate all but one spectral line) When you apply Fourrier theory to these lines you know there must be many (billions) of cycles to define the frequency so well. This is true of each photon, nothing to do with a collection of them. Recall each photon "interfers only with itself" as very low intensity, long-exposure interference pattern photos show. Typically the "length of the photon" will be most of a meter, in the sense that if the path difference is more than that, then the interfernce pattern disapears (it fades out, not as on/off switch) -This because when the path difference is too great, the shorter path and longer paths no longer have the single photon coming out of them at the same time. I have done this experiment - it is true, though impossible for humans to understand how one photon goes via two different paths, but it does or at least "knows" all about both paths. I hope you believe me when I say that low pressure gas discharge photons are typically on the order of a meter long. For a while an Hg isotope* line, which is extremely well defined in frequency was used in the definion of the meter (or some such thing). That line is also from an "almost forbidden" transition (long excited state lifetime - low transition probability) and takes a long time for the excited state to end up on the lower state of the line. I do not remember, and did not try to measure its length, but I bet that very well defined frequency photon is at least 50 meters long (assuming it is traveling in free space etc.) Where is its "central point"? What is its "central point"? ----------------------------- *I think it was Hg198, but that is by memory and may not even be an mercury isotope. In any case, the line is so sharp that it is "miles away" from the very same line from a different isotope, due to the tiny isotope effect on spectral line frequencies. A meter was a specifed number of wavelengths of that line for several years as I recall. I don't know what it is defined as now.
I don't think I invented this; but this is how I think of a photon. Photon Flux are the electric and magnetic planes that define a photon. They are strongest near the central path of the photon and diminish in strength with distance away. They are the parts of the photon that interferes causing the interference patterns. The strength of the electric and magnetic fields reach the maximum possible value for a point in space at a point in the center of the photon. These fields are the photon, it consists of nothing else. This point of saturation at the center of all photons is why photons exist as a quantum entity. The fact that points in space saturate electromagnetically is the fundamental cause of the quantum nature of the universe. A single photon consists of one wavelength. Some photons could be miles long; a meter is not difficult to visualize.
I think if a photon consists of a single wavelength then it is infinitely long according to the uncertainty principle. -Dale
Hi DaleSpam; I don't get it; one wave length is a finite number. I don't know how you can apply uncertainty to cause it to be infinite. I've always thought that uncertainty phenomena had a more mundane cause than Heizenberg's definition of it. But even with Heizenberg; I still don't get it.
Sorry, I misunderstood your point. I thought you meant that a single photon is monochromatic, in other words it is a pure light with only one wavelength (single infinitely narrow spectral peak) rather than a mixed light with a variety of wavelengths (broadend spectral peak). -Dale
also according to simple Fourrier transform of a delta function frequency, but no real photon has a pure frequency (precise energy) and this no doubt is related to the uncertainity principle. I hinted at that when discussing the Hg isotpe line by noting that the time of the transition of this very precisely known energy is large - very low transition probablility and long upper state liketimes etc. I.e if delta E is very small then delta T must be large.
I did mean that a single photon must be monochromatic. If you want the spectrum you need separate photons in each frequency. I'm not inventing this stuff. This is what is generally accepted by your peers.
I think you guys are just pulling my leg. Every real photon has a pure frequency and precise energy. It is a mixture of photons that comprise a spectrum. Edit: Even with uncertainty it is your inability to know before measurement what the precise energy is, but after you measure it, you know what it certainly was.
If a single photon is monochromatic then its length is infinite according to the Heisenburg uncertainty principle. -Dale
