What in the world does E =mc2 mean?

[εllipse]

You are reiterating the concepts since abandoned by physicists. I am very aware that Einstein proposed relativistic mass long ago.

You asked for a reference; I provided one. No need to be so harsh.

And it is this situation (measuring acceleration in a single inertial reference frame) in which relativistic mass has any relevance.

You seem to be assuming that the only thing we care about is how the world looks to us as we accelerate. But what about how things look to us as we accelerate them, while we remain inertial? For instance, when we get particles moving close to the speed of light in particle accelerators, the concept of relativistic mass does have use to us then because we do have a single inertial reference frame with which to make the measurement. Why can't we put a charged particle in a strong enough magnetic field to accelerate it faster than the speed of light? A very simple explanation is that its relativistic mass increases as we accelerate it, so its inertia/resistance to acceleration increases as well.

 

[Aer]

You asked for a reference; I provided one. No need to be so harsh.

You seem to be assuming that the only thing we care about is how the world looks to us as we accelerate. But what about how things look to us as we accelerate them, while we remain inertial? For instance, when we get particles moving close to the speed of light in particle accelerators, the concept of relativistic mass does have use to us then because we do have a single inertial reference frame with which to make the measurement. Why can't we put a charged particle in a strong enough magnetic field to accelerate it faster than the speed of light? A very simple explanation is that its relativistic mass increases as we accelerate it, so its inertia/resistance to acceleration increases as well.

I've never said you cannot do this to obtain a correct result. However, it is not necessary to use relativistic mass to get the same thing, that is all I am saying. Relativistic mass is mearly a perception in other frames - however, too many people equate this perception to be actual mass accumulation to the object in the objects rest frame. This point of view is very wrong. It is just as easy to not use relativistic mass, but I'm not going to prohibit you from doing so.

 

[Aer]

Then as the gas is heated the particles move faster. The faster they move the greater the weight.

What is the weight of a particle (you may choose any particle you wish) moving .9999c through the atmosphere?