Notices
Results 1 to 9 of 9

Thread: Deflection of light in classical physics

  1. #1 Deflection of light in classical physics 
    Forum Junior whizkid's Avatar
    Join Date
    Jan 2013
    Posts
    282
    We want to find deflection of light in classical physics considering light as any other object (Tangent lines to circles - Wikipedia, the free encyclopedia I couln't find a better picture)

    suppose light is travelling from q to P (7.5*10^10 cm, which we consider the x-axis with origin at O), space is measured in light-second, so x= 1 (= 3*10^10 cm)
    distance OP (R) is 2.5 c
    F_P = GM/ R^2 k = 23 593 at P (x=0)
    Please tell me now if the following is right, or correct what is wrong:

    - the total force F acting on light from -200 (sec) to P is the integral of cos * GM /D^2 = 2.5 * k = 59000
    (but it has the units of velocity)

    - the total deflection of light = F_T =( t: -200 - 200 sec) 59000*2 = 118000 / C

    is this correct so far?


    Last edited by whizkid; August 2nd, 2014 at 07:43 AM.
    Reply With Quote  
     

  2.  
     

  3. #2  
    Suspended
    Join Date
    Feb 2013
    Posts
    1,774
    Quote Originally Posted by whizkid View Post
    I hope Harold can say a resolutive word also about this problem: we want to find deflection of light in classical physics considering light as any other object (Tangent lines to circles - Wikipedia, the free encyclopedia I couln't find a better picture)


    is this correct so far?
    No, this is not how is done. But it will not stop you from posting errors.


    Reply With Quote  
     

  4. #3  
    Moderator Moderator Janus's Avatar
    Join Date
    Jun 2007
    Posts
    2,236
    If you consider light as you would any other object, then it would follow a hyperbolic trajectory.

    The angle of deflection for a hyperbolic orbit is found by the relationship



    b is the "impact parameter" or the closest approach the two objects would have made without gravity.
    v is the starting velocity of the deflected object, which in this case equals c.

    If you use the Sun for M and its radius for b, you get an answer of ~.875 degrees, which is in the order of 1/2 the value you get with GR. (Which is what you should expect, because the Newtonian answer works out to be 1/2 of the GR answer.
    "Men are apt to mistake the strength of their feelings for the strength of their argument.
    The heated mind resents the chill touch & relentless scrutiny of logic"-W.E. Gladstone


    Edit/Delete Message
    Reply With Quote  
     

  5. #4  
    Forum Junior whizkid's Avatar
    Join Date
    Jan 2013
    Posts
    282
    Quote Originally Posted by Janus View Post

    If you use the Sun for M and its radius for b, you get an answer of ~.875 degrees,
    thanks, Janus
    .875 degrees or seconds?
    can you give me a link where to find info about recent experiments of deflection

    Thanks for your invaluable help
    Last edited by whizkid; July 23rd, 2014 at 02:51 AM.
    Reply With Quote  
     

  6. #5  
    Moderator Moderator Markus Hanke's Avatar
    Join Date
    Nov 2011
    Location
    Ireland
    Posts
    7,302
    deflection of light in classical physics
    I think you mean "non-relativistic physics", not "classical physics". Classical physics encompass anything where quantum effects do not play a role, including GR; non-relativistic physics encompass scenarios where relativistic effects can be neglected ( can be both classical or quantum ).
    Reply With Quote  
     

  7. #6  
    Forum Junior whizkid's Avatar
    Join Date
    Jan 2013
    Posts
    282
    Quote Originally Posted by Markus Hanke View Post
    Classical physics encompass anything where quantum effects do not play a role, including GR; non-relativistic physics encompass scenarios where relativistic effects can be neglected ( can be both classical or quantum ).
    Thanks, Markus, I ignored the difference,
    in your your paper (5.8): https://www.dropbox.com/s/50rswg7ft7...ction%20SM.pdf
    you mention quasar experiments, can you give me a link where to find details?

    Thanks a lot
    Last edited by whizkid; August 2nd, 2014 at 07:26 AM.
    Reply With Quote  
     

  8. #7  
    Suspended
    Join Date
    Feb 2013
    Posts
    1,774
    Quote Originally Posted by whizkid
    please explain why we cannot use the Newronian formula F = V^2/R for the deflection of light?
    First off, the correct formula is F=m*V^2/R, not F = V^2/R. You need to learn to get your basic formulas right.

    Second off, F=m*V^2/R applies to particles that have mass, the photon DOESN'T, so the formula DOES NOT apply. This is why Soldner et al. got the wrong result.

    In order to get the right result, you need to learn GR. In order to learn GR , you need to learn calculus, something that you prefer to avoid in favor of trolling this forum.
    Reply With Quote  
     

  9. #8  
    Forum Junior whizkid's Avatar
    Join Date
    Jan 2013
    Posts
    282
    Quote Originally Posted by Janus View Post
    If you consider light as you would any other object, then it would follow a hyperbolic trajectory.
    Thanks Janus,
    Is trajectory different if you consider it like any other object?


    thanks
    Last edited by whizkid; August 2nd, 2014 at 07:21 AM.
    Reply With Quote  
     

  10. #9  
    Forum Junior whizkid's Avatar
    Join Date
    Jan 2013
    Posts
    282
    Quote Originally Posted by Janus View Post
    v is the starting velocity of the deflected object, which in this case equals c.
    .
    Can you explain why deflection is v/c (or give me any link) ? is v = 118 000 (is itcm/s?), the integral of the force acting on the photon?

    can we apply this procedure to the earth orbiting the sun?
    The earth gets roughly 1 cm/s^2 , in 400 sec it gets 400 (?) the initial velocity is 10^6, deflection is 400/10^6 = 0.0004? is this value in degrees or seconds?

    Thanks for your attention
    Reply With Quote  
     

Similar Threads

  1. Deflection of light
    By whizkid in forum Physics
    Replies: 46
    Last Post: July 25th, 2014, 02:28 AM
  2. What is trajectory Deflection Angle
    By Bjarne in forum Astronomy & Cosmology
    Replies: 3
    Last Post: January 27th, 2014, 02:16 AM
  3. A New Light In Physics
    By martillo in forum Personal Theories & Alternative Ideas
    Replies: 29
    Last Post: September 4th, 2011, 06:44 AM
  4. Calculating the value of Deflection
    By Eagle9 in forum Mechanical, Structural and Chemical Engineering
    Replies: 1
    Last Post: March 26th, 2011, 06:02 AM
  5. Replies: 41
    Last Post: June 18th, 2006, 08:12 AM
Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •