Missing Mass

[rparrish]

Has all of the energy produced by energy emitting objects, (stars, hot bodies etc) been accounted for in the estimates of total mass in the univers?

 

[kmarinas86]

This is a good page<br /><br />http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html

 

[alokmohan]

I understand photon has mass.

 

[unclefred]

Your statement that a photon has mass is fighting words for most people who regularly post on this web site. They will immediately scream that photons have no mass and that space is warped. Do a search on photon and mass and you will get lots of web sites and read up a little. The concept of zero photon mass is basic to relativity discussion.<br /><br />From a simplistic point of view, photons apprear to act like they have mass. They are affected by gravity and they impart momentum when they hit something. Assigning a mass value to a phonton and using newtonian physics will in many cases get you the right answer, or atleast get you very very close. But current theory assigns zero mass to photons.

 

[siarad]

I'm not sure I agree. I posted this earlier but have not received any replies so I guess it's stupid or badly put.

 

[killium]

E = MC2<br /><br />If a photon have 0 mass, then it gives:<br /><br />E = 0 X C2<br /><br />which gives 0 energy. Does a photon have 0 energy ? What did i get wrong ?<br /><br /><br /><br />PS. This was more well written the first time but the board crashed again. Will this board be stable one day ? <div class="Discussion_UserSignature"> </div>

 

[killium]

any takers on this one ? <div class="Discussion_UserSignature"> </div>

 

[killium]

Your explanation made me think differently about that equation. If i (now) understand it right, it could be worded like this:<br /><br />"If you take a mass M and you accelerate it to the speed of light (C^2), then you endup with energy only, which quantity is proportionnal to the original mass."<br /><br />would that needs adjustments ?<br /><br /> <div class="Discussion_UserSignature"> </div>