From: "Doug Homoelle" 
To: dwightk.elvey{at}amd.com
Cc: atm{at}shore.net
Reply-To: "Doug Homoelle" 



> >Photons DO HAVE a mass indeed, so they have no problem with gravity .
> >They behave as Newtons apples do.
>
>Hi
>  Not that I know of. My understanding is that Einstein's
>showed that it reacts differently than would be expected
>by gravity. As I recall, it was half the response but it
>has been a while since I've thought about such things.
>Dwight

Einstein's full energy equation is:

E^2 = m^2*c^4 + p^2*c^2

photon's are massless. only something that is massless can move at the
speed of light (according to Einstein).  but photons still have energy (E =
h * frequency)
you can solve for the photon's momentum with the above two equations.

E=mc^2 as generally thrown about really refers to a particle's rest energy.
If you had a particle of mass m, this is how much energy you would get if
you converted it from mass-energy to another form of energy (light-energy,
for example).

Doug

_________________________________________________________________
Add photos to your e-mail with MSN 8. Get 2 months FREE*.
http://join.msn.com/?page=features/featuredemail

--- BBBS/NT v4.00 MP