Changes

== Mass and Momentum (25)==

== Mass and Momentum (25)==

"Relativity requires that anything traveling at the speed of light must have mass zero, so it must have momentum zero. But the laws of electrodynamics require that light have nonzero momentum. "

"Relativity requires that anything traveling at the speed of light must have mass zero, so it must have momentum zero. But the laws of electrodynamics require that light have nonzero momentum. "

I'm confused how this is a counterexample to relativity. Relativity does say that anything traveling at the speed of light must have 0 rest mass, but it does not make the claim that something of zero mass has zero momentum. It's a rather famous equation that <math> E^2 = (pc)^2 + (mc^2)^2</math>. Zero mass in the context of special relativity then simply implied that <math>E = pc</math> for massless particles. It's also true that the laws of electrodynamics require light to have momentum, but I'm confused, if you follow this line of reasoning is it trying to imply that light has mass given the premise of this counterexample? Photons have <math> E=pc</math> fits perfectly well in the context of relativity and is self-consistent as far as I'm aware. ([[User:Madblueplanet|Madblueplanet]] 09:00, 20 June 2011 (EDT))

I'm confused how this is a counterexample to relativity. Relativity does say that anything traveling at the speed of light must have 0 rest mass, but it does not make the claim that something of zero mass has zero momentum. It's a rather famous equation that <math> E^2 = (pc)^2 + (mc^2)^2</math>. Zero mass in the context of special relativity then simply implied that <math>E = pc</math> for massless particles. It's also true that the laws of electrodynamics require light to have momentum, but I'm confused, if you follow this line of reasoning is it trying to imply that light has mass given the premise of this counterexample? Photons have <math> E=pc</math> fits perfectly well in the context of relativity and is self-consistent as far as I'm aware. ([[User:Madblueplanet|Madblueplanet]] 09:01, 20 June 2011 (EDT))