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#41
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On Feb 25, 7:47 am, Tom Roberts wrote:
The best model we have for the propagation of light near a massive object like the sun is GR, in which the curvature of spacetime is the important aspect in determining the path light follows. And it agrees with measurements to part-per-million accuracy over an enormous range. First, derive a set of geodesic equations a massed particle traveling at high speed near the sun. Then, gradually reducing the mass to zero and increasing the speed to c, do you see a discontinuity at mass = 0 and speed = c? As you know, the geodesic equations are independent of mass. What does that tell you when the model predicts a 1x deflection traveling at speed just a hair below c and suddenly jumps to 2x deflection at speed = c? F*cked up. |
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#42
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On Mar 1, 8:53 pm, Koobee Wublee wrote:
On Feb 25, 7:47 am, Tom Roberts wrote: The best model we have for the propagation of light near a massive object like the sun is GR, in which the curvature of spacetime is the important aspect in determining the path light follows. And it agrees with measurements to part-per-million accuracy over an enormous range. First, derive a set of geodesic equations a massed particle traveling at high speed near the sun. Then, gradually reducing the mass to zero and increasing the speed to c, do you see a discontinuity at mass = 0 and speed = c? As you know, the geodesic equations are independent of mass. What does that tell you when the model predicts a 1x deflection traveling at speed just a hair below c and suddenly jumps to 2x deflection at speed = c? Show us the mathematics in which this "2x deflection" appears, along with a consistent and clear definition of the terms. F*cked up. |
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#43
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On Mar 2, 1:54*am, Eric Gisse wrote:
On Mar 1, 8:53 pm, Koobee Wublee wrote: On Feb 25, 7:47 am, Tom Roberts wrote: The best model we have for the propagation of light near a massive object like the sun is GR, in which the curvature of spacetime is the important aspect in determining the path light follows. And it agrees with measurements to part-per-million accuracy over an enormous range. First, derive a set of geodesic equations a massed particle traveling at high speed near the sun. *Then, gradually reducing the mass to zero and increasing the speed to c, do you see a discontinuity at mass = 0 and speed = c? As you know, the geodesic equations are independent of mass. *What does that tell you when the model predicts a 1x deflection traveling at speed just a hair below c and suddenly jumps to 2x deflection at speed = c? Show us the mathematics in which this "2x deflection" appears, along with a consistent and clear definition of the terms. Just look in your books. Don't tell you collect them just to sit on. |
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#44
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On Feb 26, 3:28*pm, Cosmik de Bris
wrote: pmbwrote: On Feb 25, 2:16 am, Eric Gisse wrote: On Feb 24, 9:28 pm, "Y.Porat" wrote: On Feb 24, 11:25 pm, " wrote: Ok...so I've been wondering how on earth does gravity bend light, I mean I read all about how Einstein's General Relativity describes space-time, and when there's a mass in space-time it creates a curve(Bowling ball on a sheet or something), and that curve is Gravity, and when light passes through the curve it bends....but why? -------------------- just forget about curved spacetime light bends next topthe sun becuase of the most simple reason LIGHT HAS MASS !!! You are amazingly sure of this despite not having one shred of evidence to support your claim. Then again, it is more important to be original than be right, eh? (even Einstein ddint know to read his momentous formula E=mc^2 Show us the calculation of the deflection angle given the assumption that photons have mass. The reason that all text particles fall at the same rate given the same inititial conditions is because the gravitational mass equals the inertial mass and therefore the mass cancelts out in the equatuions of motion. Einstein predicted that light is deflected in a gravitational field because light has energy and energy has mass. You are still propagating this myth. Energy and mass are equivalent that doesn't mean that energy has mass. I disagree. And its not a myth at all. The true myth is believing otherwise. Anything which has inertial mass has energy and anything which has energy has energy has inertial mass. As Feynman wrote in the "Feynman Lectures" Vol -I page 7-11, Section entitled Gravitation and Relativity ---------------------------------------------------------------------------- One feature of this new law is quite easy to understand is this: In Einstein relativity theory, anything which has energy has mass -- mass in the sense that it is attracted gravitationaly. Even light, which has energy, has a "mass". When a light beam, which has energy in it, comes past the sun there is attraction on it by the sun. ---------------------------------------------------------------------------- Or as Einstein wrote in "The Evolution of Physics," page 221. Einstein is responding to the assertion regarding an observer in an accelerating elevator "The inside observer, who believes in the gravitational field acting on all objects in his elevator, would say: there is no accelerated motion of the elevator, but only the action of the gravitational field. A beam of light is weightless and, therefore, will not be affected by the gravitational field." ---------------------------------------------------------------------------- But there is, unfortunately, a grave fault in the reasoning of the inside observer, which saves our previous conclusion. He said : "A beam of light is weightless and, therefore, it will not be affected by the gravitational field." This cannot be right! A beam of light carries energy and energy has mass. But every inertial mass is attracted by the gravitational field as inertial masses and gravitational masses are equivalent. A beam of light will bend in a gravitational field exactly as a body would if thrown horizontally with a velocity equal to that of light. If the inside observer has reasoned correctly and had taken into account the bending of light rays in a gravitational field, then his results would have been exactly the same as those of an outside observer. ---------------------------------------------------------------------------- I understand that people may disagree with this since there is a tendancy to confuse inertial mass (which is non-zero for light) and inertial mass (which is zero for light). If you believe that you can prove otherwise then please do. Thanks. Best wishes Pete |
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#45
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On Mar 2, 12:53*am, Koobee Wublee wrote:
On Feb 25, 7:47 am, Tom Roberts wrote: The best model we have for the propagation of light near a massive object like the sun is GR, in which the curvature of spacetime is the important aspect in determining the path light follows. And it agrees with measurements to part-per-million accuracy over an enormous range. First, derive a set of geodesic equations a massed particle traveling at high speed near the sun. *Then, gradually reducing the mass to zero and increasing the speed to c, do you see a discontinuity at mass = 0 and speed = c? As you know, the geodesic equations are independent of mass. *What does that tell you when the model predicts a 1x deflection traveling at speed just a hair below c and suddenly jumps to 2x deflection at speed = c? It tells us that they are completely exclusive cases. But I do understand that YOU can't go there. Hell, you're still working on transforming algebraic domains. By the way, how's that coming along? Made any real progress lately? Have reached the level of an eighth grader yet? |
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#46
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Apologies if this is a duplicate -- I'm having some news problems.
In sci.physics Koobee Wublee wrote: On Feb 25, 7:47 am, Tom Roberts wrote: The best model we have for the propagation of light near a massive object like the sun is GR, in which the curvature of spacetime is the important aspect in determining the path light follows. And it agrees with measurements to part-per-million accuracy over an enormous range. First, derive a set of geodesic equations a massed particle traveling at high speed near the sun. Then, gradually reducing the mass to zero and increasing the speed to c, do you see a discontinuity at mass = 0 and speed = c? This is definitely a worthwhile exercise. I recommend that you do it. If you get stuck, you can find the details in Lightman et al., _Problem book in relativity and gravitation_, problem 15.9. As you know, the geodesic equations are independent of mass. What does that tell you when the model predicts a 1x deflection traveling at speed just a hair below c and suddenly jumps to 2x deflection at speed = c? It doesn't. The model predicts a deflection proportional to 1+v^2/c^2, which varies smoothly from the "Newtonian" value of 1 for small velocities to 2 as v approaches c. The moral is that before you decide that a model doesn't make sense, you should check what the model actually predicts. Steve Carlip |
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#47
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On Mar 3, 4:53 pm, wrote:
First, derive a set of geodesic equations a massed particle traveling at high speed near the sun. Then, gradually reducing the mass to zero and increasing the speed to c, do you see a discontinuity at mass = 0 and speed = c? This is definitely a worthwhile exercise. I recommend that you do it. Yes, indeed. If you get stuck, you can find the details in Lightman et al., _Problem book in relativity and gravitation_, problem 15.9. There is no need to get angry. We just have to reason all these out. As you know, the geodesic equations are independent of mass. What does that tell you when the model predicts a 1x deflection traveling at speed just a hair below c and suddenly jumps to 2x deflection at speed = c? It doesn't. The model predicts a deflection proportional to 1+v^2/c^2, which varies smoothly from the "Newtonian" value of 1 for small velocities to 2 as v approaches c. The moral is that before you decide that a model doesn't make sense, you should check what the model actually predicts. Starting with a segment in spacetime, we have the following. ds^2 = c^2 (1 - 2 U) dt^2 - dr^2 / (1 - 2 U) - r^2 dO^2 Where ** U = G M / c^2 / r ** R = Radius of the sun The photon also propagates through space or spacetime with an accumulation in spacetime of exactly zero. Thus the geodesic model that dictates the path through spacetime is the one that accumulates the least amount of spacetime is indeed absurd because it would never allow a coherent trajectory for light. Thus, this derivation falls back to the Fermat's principle where the geodesic path follows the path with the least accumulated amount of time. Yes, this violates the essence of SR which dictates relative simultaneity. Nevertheless, this model of geodesics does allow a photon deflection with the photon having a coherent path through out its course of being deflected by the sun. In doing so, we can easily find the Lagrangian that satisfy the minimum elapsed time to be the following. L c^2 = (ds/dt)^2 / (1 - 2 U) + (dr/dt)^2 / (1 - 2 U)^2 + r^2 (dO/ dt)^2 / (1 - 2 U) = c^2 Where ** L = 1, the Lagrangian ** T = Integral(t1, t2)[L dt], the action of accumulating time We find the following Euler-Lagrange equations that indicate conserved quantities. ** ds/dt = K (1 - 2 U) ** dO/dt = H R c (1 - 2 U) / r^2 Where ** K, H R c = Integration constants So, the Lagrangian becomes the following. K^2 (1 - 2 U) + (dr/dt)^2 / c^2 / (1 - 2 U)^2 + H^2 R^2 (1 - 2 U) / r^2 = 1 Presenting the above equations and the equation describing the conservation of angular momentum side by side, we have the following. ** r^4 (dO/dt)^2 / c^2 R^2 = H^2 (1 - 2 U)^2 ** (dr/dt)^2 / c^2 = (1 - 2 U)^2 (1 - K^2 + 2 K^2 U - H^2 R^2 / r^2 + 2 H^2 R^2 U / r^2 Combining the above equations together, we have the follwing. r^4 (dO/dr)^2 / r^2 = H^2 / (1 - K^2 + 2 K^2 U - H^2 R^2 / r^2 + 2 H^2 R^2 U / r^2) Or r^4 (dO/dr)^2 / r^2 = H^2 / (1 - K^2 + 2 u K^2 R / r - H^2 R^2 / r^2 + 2 u H^2 R^3 / r^3) Where ** U = u R / r ** u = G M / c^2 / R Applying the boundary condition, we find the following. K^2 = 1 - B^2 Where ** B = Speed of the particle at (r = infinity) Taking the sun away hypothetically, at the perihelion, the speed remains B. Thus, we find the following. H^2 = B^2 Then, the trajectory equation becomes the following. r^4 (dO/dr)^2 / r^2 = B^2 / (B^2 + 2 u (1 - B^2) R / r - B^2 R^2 / r^2 + 2 u B^2 R^3 / r^3) At the perihelion, (dr/dt = 0), and we find the distance that is deflected into the sun by the following amount. dR / R ~= u / (B^2 + 4 u (1 - B^2)) ~= u / B^2 Where ** dR = Deflected distance into the sun ** B^2 u Define the following. p = R / r - u / B^2 The trajectory equation simplifies to the following. (dO/dp)^2 ~= 1 / (1 - 2 u p - p^2 + 2 u p^3) Or dO/dp ~= 1 / sqrt((1 - 2 u p) (1 - p^2)) ~= (1 + u p) / sqrt(1 - p^2) Twice the integral with proper integration boundaries, we have the following. 2 O = 2 integral(-u / B^2, 1)[dp (1 + u p) / sqrt(1 - p^2)] Or 2 O ~= 2 (sin^-1(1) - sin^-1(-u / B^2) + u sqrt(1 - u^2 / B^2)) Or 2 O ~= pi + 2 u (1 + 1 / B^2) If (B^2 = 1), we have a deflection of (4 u) which is twice the Newtonian result. However, at the speed just below 1, the deflection angle is higher than twice the Newtonian result. I don't know where the maximum deflection is as predicted by GR with the geodesics obeying Fermat's principle. Perhaps, your students with lots of time at hand are willing to sort through the second or third order effects to find it. So, after doing the mathematics as you have wisely recommended me to do, I have to admit that I do not find this discontinuity I was expecting. However, the absurdity in GR is in deflection more than twice the Newtonian result at slightly lower speed than the speed of light. |
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#48
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On Feb 29, 8:04*pm, Igor wrote:
On Feb 29, 2:35*am, "Y.Porat" wrote: On Feb 28, 11:19*am, "Artful" wrote: "Y.Porat" wrote in message .... so thje formula shoul not be E=gamma m * times c^2 but .... E/Gamma = mc^2 !! That is the same formula .. just written slightly differently. AND m REMAINS * * COOOOOOOONSTANT * !! *(:-) It is constant 9assuming you are talking about the one object) in both formulas. *'m' means mass (rest mass or invariant mass) .. it doesn't change. *rewriting the formula does not make any difference whatsoever .. except that the formula you propose is less useful in that neither side directly gives you a meaningful value (ie most useful formulas have a single symbol on one side, and an expression on the other side that calculates the value for that *formula. ---------------- thas exactly the point !! *IT IS THE SAME FORMULA WITH A BASICALLY DIFFERENT PHYSICAL UNDERSTANDING!! And you're physical understanding is certainly different.- Hide quoted text - - Show quoted text - --------------- yess indeed and some people already told me that i am an orriginal thinker now just wtite it before you who told you that for the first time !! and please dont forget ..... Y.Porat ------------------------------------ |
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#49
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On Mar 3, 8:31*pm, Igor wrote:
On Mar 2, 12:53*am, Koobee Wublee wrote: On Feb 25, 7:47 am, Tom Roberts wrote: The best model we have for the propagation of light near a massive object like the sun is GR, in which the curvature of spacetime is the important aspect in determining the path light follows. And it agrees with measurements to part-per-million accuracy over an enormous range. First, derive a set of geodesic equations a massed particle traveling at high speed near the sun. *Then, gradually reducing the mass to zero and increasing the speed to c, do you see a discontinuity at mass = 0 and speed = c? As you know, the geodesic equations are independent of mass. *What does that tell you when the model predicts a 1x deflection traveling at speed just a hair below c and suddenly jumps to 2x deflection at speed = c? It tells us that they are completely exclusive cases. exclusive cases ?? (:-) nice we are doing some progress!! now if exclusive... why not doing a little further step: if the photon is an exclusive case why should it not be the only mass that can move at c ?? (:-) and you see as well that while masses are being s,aller they can reach CLOSER AND CLOSER TO c !! so why not at a limit case not to reach exactly c ?? and i still didnt mension that in E photon = hf(it id 6.6 x 10- ..... times 1 kilogram times 1 meter ^2/1 second !! so if my eyesight is not wronn i see even through my eyeglasses the KILOGRAM there do you have any idea what is that **Kg* doing there? do you have an idea how a physics formula is built and used ???.... that h is is hiding something for peoe who didnt use their own mind even theoretically ........ now again dont please forget who told you that the first time ATB Y.Porat ------------------------- *But I do understand that YOU can't go there. *Hell, you're still working on transforming algebraic domains. *By the way, how's that coming along? Made any real progress lately? *Have reached the level of an eighth grader yet?- Hide quoted text - - Show quoted text - |
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#50
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On Mar 4, 2:53*am, wrote:
Apologies if this is a duplicate -- I'm having some news problems. In sci.physics Koobee Wublee wrote: On Feb 25, 7:47 am, Tom Roberts wrote: The best model we have for the propagation of light near a massive object like the sun is GR, in which the curvature of spacetime is the important aspect in determining the path light follows. And it agrees with measurements to part-per-million accuracy over an enormous range. First, derive a set of geodesic equations a massed particle traveling at high speed near the sun. *Then, gradually reducing the mass to zero and increasing the speed to c, do you see a discontinuity at mass = 0 and speed = c? This is definitely a worthwhile exercise. *I recommend that you do it. If you get stuck, you can find the details in Lightman et al., _Problem book in relativity and gravitation_, problem 15.9. As you know, the geodesic equations are independent of mass. *What does that tell you when the model predicts a 1x deflection traveling at speed just a hair below c and suddenly jumps to 2x deflection at speed = c? It doesn't. *The model predicts a deflection proportional to 1+v^2/c^2, which varies smoothly from the "Newtonian" value of 1 for small velocities to 2 as v approaches c. The moral is that before you decide that a model doesn't make sense, you should check what the model actually predicts. Steve Carlip ------------------ lie!! the model ddint predict it was **fiddling** the data to the model Y.Porat ----------------------------- |
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