Photons lack mass, but they do not lack mass-energy, so they do behave
as a source for the bending of space. So I say that they do tug, ever
so slightly back on the sun.
________________________
Joel Rauber
Department of Physics - SDSU
Joel.Rauber@sdstate.edu
605-688-4293
| -----Original Message-----
| From: phys-l-bounces@carnot.physics.buffalo.edu
| [mailto:phys-l-bounces@carnot.physics.buffalo.edu] On Behalf
| Of David Ward
| Sent: Friday, October 12, 2007 5:22 PM
| To: phys-l@carnot.physics.buffalo.edu
| Subject: [Phys-l] starlight deflection
|
| Dear Phys-L Colleagues:
|
| Starlight deflects as it grazes the sun, as the sun's mass
| warps space...so the vector momentum of a photon is altered
| by its encounter with the sun. But an altered momentum means
| that a force was exerted. So, does the starlight tug
| ever-so-slightly on the sun? Photons lack mass, so I suspect
| they don't warp spacetime...
|
| In any event, this boils down to "if the sun exerts a force
| (momentum alteration) on a photon does the photon do the same
| to the sun?" My general relativity is so very poor- I suspect
| the answer may lie there.
|
| This is a student question, and I'd be very grateful for any
| response you could share. Thanks!
|
| david
|
| David Ward
| Professor of Physics
| UNU# 3160
| Dept. of Physics
| Union University
| 1050 Union University Drive
| Jackson, TN 38305-3697
| office (731)661-5241
| FAX (731)661-5175
| dward@uu.edu
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