am i write in thinking a photon has no mass

[jackles]

am write in thinking that a photon is massless because all its energy is speed.

[MMasz]

Yes, you are correct. They do not have mass as in relation to matter.

[jackles]

ok thanks .i now know for certain un till some one says they do have mass.which they will.or is it they photons only have mass when they change state.which must be when they are slowed.but that cant be because time would just pass fasterrelative to them the photon.

[Immanuel Can]

A photon has no mass?

I didn't even know they were Catholic.

[jackles]

ha ha.

[HexHammer]

Anything must have mass in order to exist, mayb they have particles not sensetive to conventional forces.

[thedoc]

I believe it has been demonstrated that when an object absorbs light it gains mass, and when it emits light it looses mass.

[jackles]

yes that figures theo because massless speed energy goes back to mass state energy.energy is all relative then.

[Kuznetzova]

Photons have no mass, but they still have momentum.
This seems like a paradox at first. But the reason is because of relativistic effects.

http://hyperphysics.phy-astr.gsu.edu/hb ... om.html#c2

[thedoc]

'K' please stop pretending that you know something, it makes you look silly.

[Kuznetzova]

'K' please stop pretending that you know something, it makes you look silly.

[jackles]

so energy in just timespace terms is light.or light = time divided by space in terms of energy.so can we say energy = time divided space .as in waves of time divided by waves of space equals energy position +or- gravity.

[Blaggard]

Well you can't really prove it has no mass science doesn't do absolutes, but the lower limit where it may provably have mass, is so small, that even if it did have mass it's effect would be so tiny as to make no appreciable difference to the theory. Ie I think it's now in the pico or 10^-12 = 0.000000000001 range of non detection of mass.

Anything must have mass in order to exist, mayb they have particles not sensetive to conventional forces.

I don't think that is so, how did you come by this claim?

[HexHammer]

I don't think that is so, how did you come by this claim?

Purely spekulation.

Just skip the last part.

[Blaggard]

Incidentally the reason it was thought the photon was massless was because of special/general relativity and the lorentz transforms and how they fitted with e=mc^2, if you plug mass into either general or special relativity you end up with nigh on infinites or nigh infinitessimals that don't work and wouldn't agree with experiment, assuming it has a mass value of above a certain amount, the smaller that value the less it matters. If you'll pardon the pun.

Mind you it was thought that neutrinos had to be massless, and turns out they were wrong about that, they have mass and what's even odder is they only have left handed spin, but that's another topic altogether.