Yo my fellow science lovers :).

I have a tricky question for you guys, I asked my physics prof but he did not have a answer to my question but I hope someone does :).

Question: If a particle can not be accelerated/move to/at the speed of light, how come only light can move at the speed of light?.

According to einsteins E=mc^2, energy is mass and vice versa. So light must have a mass and at the same time it behaves like a wave.
But something with a mass can not travel at the speed of light. From my perspective this is a major logic error. I don't have a physics Ph.d or something, just a curious fellow

i am thinking really hard about this

cannot acces site :S

from the other site, e = mc^2 is not the complete equation, there is a momentum term in it as well.


then there was another reply saying that its called massless because its rest mass is zero, where their relativistic mass is not zero.

This post was edited by cialda on May 7 2012 07:12am

and does it explain why a foton is the only "particle" that can travel at the speed of light?

all massless particles move at the speed of light...that's just an inherent property of massless particles...i'm fairly certain photons are the only known independent massless particles.

think of mass like the resistance to acceleration (a=F/m)

This post was edited by Derkaderk on May 7 2012 12:20pm

E=mc^2 does not apply to moving particles. The energy term just indicates how much energy there would be if ALL the mass in that object was converted into energy.

For a moving object, E = gamma*mc^2. At the speed of light, gamma is undefined so the equation does not hold.

a photons rest mass is zero, you dont see it creating a gravitational field of any kind



in fact, iirc at the speed of light you'll have an infinity-multiplied-by-zero problem, which is equivalent to 0/0, which is indeterminate but can have a value
that equation is just a wrong way of obtaining the E value, but it itself shows that it can have energy E.

This post was edited by Ocen on May 8 2012 12:07am