# Einstein mass energy equation

## Main Question or Discussion Point

according to the theory, when an object is moving in the speed of light, the object will lose it mass and the lost mass will transform into energy.so when the object is moving,if we provide the same energy the object losses to it, will the mass of the object changes?

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DaveC426913
Gold Member
Your initial premise about relativity is in error. No object with mass can achieve the speed of light.

But accoring to the equation E=mc^2 , isn't that c is refer to the speed of light?

DaveC426913
Gold Member
But accoring to the equation E=mc^2 , isn't that c is refer to the speed of light?
Yes. But you cannot deduce from the formula what you have tried to deduce.

But isn't the particles losing it's mass when it is travelling in he speed of light?

DaveC426913
Gold Member
But isn't the particles losing it's mass when it is travelling in he speed of light?
No.
Massless particles (bosons), such as photons, always travel at the speed of light.
Massive particles (fermions), such as electrons or protons, can never reach the speed of light.

You can annihilate massive particles, which will release a burst of photons, and those photons will move away from the interaction at the speed of light. But you don't start with massive particles and accelerate them to c.

OK, thx dude,but i wanmaask if eectroms and protons will lose mass when they approch8ngthe sped of light?

PeterDonis
Mentor
2019 Award
i wanmaask if eectroms and protons will lose mass when they approch8ngthe sped of light?
No. Particles gain mass (more precisely, they gain energy, which is one possible meaning of the term "mass"--usually the term "relativistic mass" is used for this) as they approach the speed of light. Please review the following links for more information:

http://en.wikipedia.org/wiki/Mass_in_special_relativity

http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html

I'm closing this thread since this is a very basic issue and you should take some time to study it before asking further here. If you still have questions once you've studied, please open a new thread.