do photons have mass?

Question

hi i am fourteen and love physics but i am stuck... okay how can neutrinos reach and or exceed the speed of light? if they have mass and we calculate energy with E^2=(MC^2)^2+(PC)^2 then its impossible? unless photons have mass... which would make sense because they add weight to objects, they are effected electromagnetically, and by gravity? so do they have mass? please physicists out their please help me understand!

Answer 1

Neutrinos cannot reach or exceed the speed of light. The experiment that was believed to have demonstrated that was in error.



Photons have no REST mass (because they don't interact with the Higgs field). Photons have energy and can be equated to a mass equivalent thru e=mc^2.



Photons not only are affected by gravity, they also generated gravity. The energy density component of the energy-momentum tensor in General Relativity can be either the energy density of the rest mass of a particle or the energy density of an electromagnetic field.

Answer 2

Photons do no have mass. They do have energy though....and they have momentum.

also....PHOTONS DO NOT NEED TO HAVE MASS TO BE EFFECTED BY GRAVITY.

Check out these resources.

http://www.youtube.com/watch?v=A5IlKfdbjAk

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961102.html

Answer 3

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