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bobie
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Hi,
I am trying to understand the difference between GR and classical deflection of light by the Sun.I found this
R = 2.5c (7.5*10^10 cm) point of impact, x distance of light from R in light-seconds, r (=√x2 +R2) distance of light from center of sun and then distance sun-earth = 200c (http://www.wolframalpha.com/input/?i=integrate+y=+2.5^3/+(sqrt(x^2+2.5^2))^3+from+0+to+200) = 2.4998
and distance star-sun -∞ (http://www.wolframalpha.com/input/?i=integrate+y=+2.5^3/+(sqrt(x^2+2.5^2))^3+from+-+infinity+to+0) = 2.5 (R/c)
the non relativistic pull should then be [itex]\frac{GM}{R^2} = 23600 *2*2.5 \frac{2*R}{c} → \frac{2 GM}{Rc} ≈ 118 000 cm/s^2 [/itex]
Can you check if it is right and clarify a couple of points:
- do observed light beams actually 'graze' the Sun? what is the usual distance of the observed beams? can you give me a link where to find details of recent observations? I read that deflection has been adjusted to 1.67'',but, at what distance from the center of the sun?
- In order to get the global pull by the sun we must multiply gsun (the force at x=0 (R)) by the integral and by 2 because the pull is exerted from -∞ to 200. This seems the obvious classical procedure, but BvU (I am not sure about mfb) considers this factor as the relativitic γ-factor, which would give 4 GM.
what is correct?
Your help is greatly appreciated
I am trying to understand the difference between GR and classical deflection of light by the Sun.I found this
I do not now how to apply a 'weight sin3' so I worked out my own equation in which;BvU said:They want us to integrate dx / c from -∞ to +∞ with a weight sin3Θ
(Hint: x = R/tanθ ; change to dθ ) My guess is that the integral gives 2R/c.
Contrary to what Mentor claims: the 2 is still important. Spectacularly so in 1919 when Einstein was proved right...
R = 2.5c (7.5*10^10 cm) point of impact, x distance of light from R in light-seconds, r (=√x2 +R2) distance of light from center of sun and then distance sun-earth = 200c (http://www.wolframalpha.com/input/?i=integrate+y=+2.5^3/+(sqrt(x^2+2.5^2))^3+from+0+to+200) = 2.4998
and distance star-sun -∞ (http://www.wolframalpha.com/input/?i=integrate+y=+2.5^3/+(sqrt(x^2+2.5^2))^3+from+-+infinity+to+0) = 2.5 (R/c)
the non relativistic pull should then be [itex]\frac{GM}{R^2} = 23600 *2*2.5 \frac{2*R}{c} → \frac{2 GM}{Rc} ≈ 118 000 cm/s^2 [/itex]
Can you check if it is right and clarify a couple of points:
- do observed light beams actually 'graze' the Sun? what is the usual distance of the observed beams? can you give me a link where to find details of recent observations? I read that deflection has been adjusted to 1.67'',but, at what distance from the center of the sun?
- In order to get the global pull by the sun we must multiply gsun (the force at x=0 (R)) by the integral and by 2 because the pull is exerted from -∞ to 200. This seems the obvious classical procedure, but BvU (I am not sure about mfb) considers this factor as the relativitic γ-factor, which would give 4 GM.
what is correct?
Your help is greatly appreciated
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