# Light with Gravity and Mirrors

1. Nov 4, 2008

### Naty1

I was just looking at how a gravitational mass bends/curves light:
A sketch is at:

http://www.mathpages.com/rr/s6-03/6-03.htm

(It resembles spaghetti being turned on a fork...!!)

This is eerily similar to a mirror bending/reflecting light without the influence of any gravity.

Each enables us to see behind an object....as does "gravitational lensing" does; looks like some light is bent 180 degrees...turned around...

What else bends light???:

Does an an electromagnetic field ??;ie, a charged particle?....I think "no" because the EM field is not self interacting as is the gravitational field??? But then how did cosmic opaqueness clear following the "bang" (big or bounce or quantum)....straight line collisions between photons and ions???

Strong nuclear force?

Going from one optical density to another (prism, for example; or a glass of water) does for sure....

What other phenomena curve/bend light???

Would any of these also work for the strong force, also mass zero??? so what??

Are there hints hidden in these interactions regarding the nature of light?? other than wave/particle dualities...??

(I am clearly spending too much time on this forum!!!!)

2. Nov 5, 2008

### DrGreg

Light can bend relative to an accelerating observer.

I was curious to see what happens here so I did a calculation (in Rindler coordinates) for a uniformly accelerating observer in flat spacetime. Light that is emitted from the observer in a direction perpendicular to the acceleration follows a curve (relative to the observer) that is, in fact, the arc of a circle of radius $c^2/a$, heading towards, but never quite reaching, the event horizon at a perpendicular distance of $c^2/a$ behind the observer. This is somewhat surprising because in relativity you usually expect to get hyperbolas instead of circles or parabolas.