Johnny5 Posted April 14, 2005 Share Posted April 14, 2005 I'm pretty sure that photons mediate the gravitational force now. Does anyone disagree? He was wondering about how it is that the universe can expand, and take the matter along with it... inquiring into the method through which space couples to matter. But a true vacuum can not ever couple to matter. So, he made me think about what really is responsible for the gravitational force. I know it's not action at a distance. Or I should say,"It isn't instantaneous action at a distance." If the sun suddenly stopped existing, we here simultaneous to that, would still follow an elliptical path around the place in the solar system, which is the center of inertia we currrently orbit. Then, in 8 or so minutes, it would be as if the umbilical cord was cut, and we would shoot off out of the solar system, in a straight line at a constant speed, by Galileo's/Newton's Law of inertia. Why do I say 8 minutes, and not simultaneously? The answer lies in Gravitational field theory, and the "retarded gravitational potential." We know for a fact, that our sun emits something, which we call light. At least that's what it was first called. It gives us heat, and warmth, and makes plant's grow, and allows us to see the surfaces of things. Then with photon theory, we now say particles. The sun emits particles, which get called photons. But whatever is really going on, is going on in the local region of space surrounding the earth, where these 'photons' and the material of the earth finally get a chance to interact somehow. Fourier series can describe it. Some kind of wave superposition going on, which leads to the elliptical orbit of the center of inertia of the earth, in the rest frame of the center of mass of the solar system. Like i said, spyman gave me an idea. Regards Link to comment Share on other sites More sharing options...
Bob182 Posted April 14, 2005 Share Posted April 14, 2005 I'm pretty sure that photons mediate the gravitational force now. So if I were to enclose myself in a sufficient amount of lead, I would become weightless? Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 So if I were to enclose myself in a sufficient amount of lead, I would become weightless? Why would you pick lead? To know the answer to this, to prove you know it, would be very complicated. BUt here.... Let it be stipulated that something emitted by our sun, is what by and large, causes the earth to take its elliptical path around the sun. If you could build something to block that which the sun emits, and shield the earth from that which causes it to move in its curved path, then indeed the earth would fly off, as though you reduced the local gravitational potential to zero. So... If you then took this material whatever it was, and encased yourself in a sphere, and entered outer space, it would block that which would otherwise keep you in orbit about the sun. But in space you are already weightless. But your idea is consistent with the notion that photons mediate the gravitational force. A shield would do just that, shield the interior from external effects. Link to comment Share on other sites More sharing options...
J.C.MacSwell Posted April 14, 2005 Share Posted April 14, 2005 So if I were to enclose myself in a sufficient amount of lead, I would become weightless? You can run (orbit) but you cannot hide! Link to comment Share on other sites More sharing options...
blike Posted April 14, 2005 Share Posted April 14, 2005 I would assume he picked lead because it blocks most electromagnetic radiation (i.e. photons), even x-rays. Also, what does your idea have to say about general relativity? Was Einstein's model wrong? Link to comment Share on other sites More sharing options...
Bob182 Posted April 14, 2005 Share Posted April 14, 2005 Let it be stipulated that something emitted by our sun' date=' is what by and large, causes the earth to take its elliptical path around the sun. QUOTE'] and that something emitted by the earth causes the moon to take its orbit around the earth Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 Let it be stipulated that something emitted by our sun' date=' is what by and large, causes the earth to take its elliptical path around the sun. QUOTE'] and that something emitted by the earth causes the moon to take its orbit around the earth Actually, I would prefer to answer this question mathematically. Not necessarily. It's getting complicated to answer correctly, very fast. You need a mathematical model of gravity at this point in the discussion. PS: Gravity is an electromagnetic wave, better to say, superposition of them. And then you have to link this to the path traced out in the right frame. Link to comment Share on other sites More sharing options...
Jacques Posted April 14, 2005 Share Posted April 14, 2005 I'm pretty sure that photons mediate the gravitational force now. Does anyone disagree? I disagree. You don't give a hint of how gravity would be mediated by photon... Link to comment Share on other sites More sharing options...
Bob182 Posted April 14, 2005 Share Posted April 14, 2005 PS: Gravity is an electromagnetic wave' date=' better to say, superposition of them. And then you have to link this to the path traced out in the right frame.[/quote'] so an object that emits more electromagnetic radiation has a higher gravitational attraction? Link to comment Share on other sites More sharing options...
island Posted April 14, 2005 Share Posted April 14, 2005 If the sun suddenly stopped existing' date=' we here simultaneous to that, would still follow an elliptical path around the place in the solar system, which is the center of inertia we currrently orbit. Then, in 8 or so minutes, it would be as if the umbilical cord was cut, and we would shoot off out of the solar system, in a straight line at a constant speed, by Galileo's/Newton's Law of inertia. [/quote'] What if the sun just stopped shining? Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 I disagree. You don't give a hint of how gravity would be mediated by photon... I only just started thinking about this recently. No model yet. Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 so an object that emits more electromagnetic radiation has a higher gravitational attraction? Before I attempt to answer this, what is the flux of the sun at the surface of the earth, do you know its value? Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 What if the sun just stopped shining? The answer to the question, must be centered around the concept of inertia then. The amount of gravity due solely to the sun, in the local region of space to the earth, is related chiefly upon the inertia of the sun. This fact will not be ignored in the final solution of the problem. With that in mind, there has to be a connection between the amount of inertial mass of the sun, call it gravitational mass if you want, and the photons being emitted by it, which are the carriers of the sun's gravitational effect upon the earth, which is as a force, which accelerates the earth, and therefore, alters the path of the earth, making it deviate from a straight line, it might otherwise take. The shining is from the photons, but they in turn are emitted in enormous numbers, because there is so much matter inside the sun, and that amount of that matter is related to the total inertia of the sun. I see your point... A ball of matter which isn't shining, such as a black hole, would still have a gravitational effect upon material that enters its nonzero gravitational potential somewhere in space. But photons are that which travel at c, not necessarily those in the visible spectrum. There are two variables that I can think of, that might influence the total amount of gravity, in the field, and they are: Intensity of radiation Energy per photon I have to keep thinking about this. [math] \psi = 1395\frac{watts}{m^2} [/math] This is the intensity of solar radiation at the surface of the earth. Assume the sun is an isotropic radiator. So there will be EIRP formulas, that is, equivalent isotropic radiated power. From memory, they involve natural logs, I forget the exact formulas. Intensity of radiation falls off as 1/r^2. Any help would be appreciated. Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 I want to compute the number of photons emitted by the sun per second. Assume that the sun is an isotropic radiator. Denote the energy per photon E as: [math] E = \hbar \omega = hf [/math] Now, we know the approximate earth-sun distance. Using google we find that: [math] R_{earth-sun} = 1.5 \times 10^{11} \text{meters} [/math] Which is equivalent to 150 million kilometers. Now, as the photons move outwards, the intensity falls off. The photon density decreases, over any spherical patch. Just think of a pin cushion. When you are near the object with the pins in it, there are say ten needles passing through an area of say one square millimeter. Now, move your tiny one millimeter square box away from the pincusion, and soon less needles will be passing through that same square. The number of needles per unit area, decreases as you move away from the pin cushion. You experience this basic effect, every time you move your face towards a light bulb. The number of photons hitting your face is larger when your face is nearer to the light bulb then when it is further away. I am trying to remember the formula for equivalent isotropic radiated power. Here are some formulas about it Antenna pattern measurment Link to comment Share on other sites More sharing options...
Bob182 Posted April 14, 2005 Share Posted April 14, 2005 Assume that the sun is an isotropic radiator. Are you referring to it radiating isotropically over all solid angle' date=' or isotropically throughout the electromagnetic spectra? The sun's spectra is approximately that of a black body at 5780 K (e.g. see here) As for the intensity, that of isotropic radiation will drop off as 1/r^2. Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 Are you referring to it radiating isotropically over all solid angle' date=' or isotropically throughout the electromagnetic spectra? The sun's spectra is approximately that of a black body at 5780 K (e.g. see here) As for the intensity, that of isotropic radiation will drop off as 1/r^2. I was just thinking of it as isotropic over all solid angle. I used to know all the formulas, for antenna gain, etc. They can come back if i need them to solve this. Here is a link to Stefan's law Here is Stephan's constant: [math] \sigma = 5.76 x 10^{-8} \frac{J}{s m^2 K^4} [/math] The units are joules per second, per square meter, per degree Kelvin to the fourth. So if we multiply stephan's constant by the thermodynamic temperature to the fourth, then the final units will be Joules/second per square meter. Joule per second is unit of power called watts. so.. Units will be Watts per square meter, which is a unit of intensity. And in the formulas I used to use for EIRP, we use the letter psi in order to denote the flux density of an emitter, which has units of Watts/square meter. So using psi to denote the flux density, we have: [math] \psi (T) = \sigma T^4 [/math] What I now need, is a formula for psi, in terms of the distance from the radiation source. The surface area of a sphere is: [math] 4 \pi R^2 [/math] The radius of earth is: 6,378 kilometers 6,378,000 meters Perform the analysis in the rest frame of the sun. Imagine a sphere of photons radiated outwards. Denote the number of photons emitted per second by N. The speed of a photon in the rest frame of the emitter is: 299792458 meters per second Now, the total number of photons on an expanding sphere is an S frame constant, since the speed of the photons in the frame are all the same, namely c=299792458 m/s. Now, eventually, the photons will encounter the earth. And when they do, only one side of the earth will be facing the sun. From the photons point of view, there is a circular area in their way, of area pi R^2, where R is the radius of the earth. Now, we have measured the intensity of the sun at the surface of the earth, as approximately 1400 watts per square meter. Link to comment Share on other sites More sharing options...
swansont Posted April 14, 2005 Share Posted April 14, 2005 I'm pretty sure that photons mediate the gravitational force now. Does anyone disagree? The light we see points toward where the sun was, 8 minutes ago, i.e. there is aberration. The gravitational vector points to where the sun is now. (This fact is often mistaken to imply that gravity is instantaneous.) How would you reconcile this? Link to comment Share on other sites More sharing options...
J.C.MacSwell Posted April 14, 2005 Share Posted April 14, 2005 The light we see points toward where the sun was, 8 minutes ago, i.e. there is aberration. The gravitational vector points to where the sun is now.[/b'] (This fact is often mistaken to imply that gravity is instantaneous.) How would you reconcile this? Then why is there a perhelion shift for orbits? Link to comment Share on other sites More sharing options...
us.2u Posted April 14, 2005 Share Posted April 14, 2005 Doe's the same set of rules apply to extra-solar planets? Link to comment Share on other sites More sharing options...
bascule Posted April 14, 2005 Share Posted April 14, 2005 M-theory speculates that the Higgs field and thus the gravitational force is composed of closed p-branes which are not bound to a d-brane like the open p-branes that compose all matter/energy/other forces are. The strings of these p-branes can freely flow between universes bounded by different d-branes, so the force of gravity is diluted across all dimensions. This would explain why we have never observed gravitons in particle accelerators; they are not d-brane bound and can escape into another dimension before we can observe them. The Higgs field is thus manifested in a way that change of velocities requires a change in the flow of multidimensional gravitons about you. In order to change your velocity you must reshape the flow. The most compelling coincidence is that the characteristics of gravitons as predicted by both quantum and M-theory (massless spin 2 particle) match up. If gravity is mediated by photons, then why is it so compratively weak to the other forces? Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 If gravity is mediated by photons' date=' then why is it so compratively weak to the other forces?[/quote'] Everything else you said was nonsense, in my ignorance I can say that, not to be offensive but its not Euclidean. Anyhow... I think this is it. Deductive, inductive it doesnt matter. I think photons mediate the gravitational force. Some other people seem to think the speed of gravity is near 299792458, so that should register at some point. It can't be infinite speed. It can't be speed zero. Therefore, it's somewhere in the middle. There is this magical speed that popped up in Maxwell's equations. And there is this magical speed that popped up in Fizeau's measurement. Change the name of them to graviton, and I don't think that changes the underlying physics of what is going on at the level of the fundamental interaction. We are going to end up always using wave superposition to describe the phenomenon, I just know it. I haven't done enough experiments with lasers, but people tell me they can attract. That beams can attract one another, and the force of attraction depends upon the photon frequency. These are the only clues nature will ever give us. All I would ask is this... If gravity is mediated by photons... could we then combine gravity and electrodynamics? Regards PS: No, those aren't the only clues. But something is here. Something in the thought that gravity is mediated by photons. It just makes sense for some reason. Something like this, which cannot be deduced, is entirely empirical. And empirical science is the way to go, even if you can deduce something, it's always better to figure it out by experiment. That being said, I will defer to someone who has done those laser experiments I mentioned. What I will say is this... If i knew for sure two laser beams attracted one another, i would just ask what the force constant was. If it was G, this would be a closed issue. Link to comment Share on other sites More sharing options...
swansont Posted April 14, 2005 Share Posted April 14, 2005 Then why is there a perhelion shift for orbits? Is there a perihelion shift that is not explained by GR? Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 Is there a perihelion shift that is not explained by GR? Swansont, what is a perihelion shift exactly? Regards Link to comment Share on other sites More sharing options...
Bob182 Posted April 14, 2005 Share Posted April 14, 2005 What I will say is this... If i knew for sure two laser beams attracted one another' date=' i would just ask what the force constant was. If it was G, this would be a closed issue.[/quote'] As far as I'm aware, such experiments are performed in plasmas and other non linear mediums, and are well known - e.g. google "self-focusing effect" Lasers do not interact in this way in a vacuum. Link to comment Share on other sites More sharing options...
Johnny5 Posted April 14, 2005 Author Share Posted April 14, 2005 As far as I'm aware' date=' such experiments are performed in plasmas and other non linear mediums, and are well known - e.g. google "self-focusing effect" Lasers do not interact in this way in a vacuum.[/quote'] I'm looking for a unifying principle Bob... how can anyone perform an experiment like that in a plasma??? I definitely need to read up on more experiments though. I just read up about it... self-focusing effect. Do you know much about it? Just read something called, "Observation of spatiotemporal self-focusing of spin waves in magnetic films." What is a "spin wave"? Link to comment Share on other sites More sharing options...
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