Re: Does Newtonian gravity bend light?

[Leigh Palmer <palmer@SFU.CA>]

> One of the textbooks on my desk says regarding predictions of GR "Gravity
> should bend light rays, an effect not predicted by Newtonian mechanics
> because light has no mass."  Yet
> <http://www.theory.caltech.edu/people/patricia/lclens.html> claims that
> Newtonian gravity bends light, just less than Einsteinian gravity does.
> What gives?
>
> Thanks,
> Larry

If one imbues light with mass m and momentum mc, and then applies
Newtonian methods, one gets a gravitational effect one-half as
great as that calculated using GR. This assignment of mass to
electromagnetic radiation is in concert with Eistein's equivalence
of mass and energy (E=mc^2) and is mass of the old fashioned kind,
what we old timers call "relativistic mass". In modern jargon
electromagnetic radiation is massless.

Leigh