Dirac's Rest Mass in Minowski Spacetime

[Bob Dylan]

Dirac's rest mass seems to be expressed as a fourth dimension. If we were to try to include this rest-mass dimension into Minowski space time, could it be expressed as a distance in space? S^2=x^2+y^2+z^2+(rest-mass dimension)^2-(ct)^2?

 

[vanhees71]

Think about the dimensions in your expression! You'll see that it doesn't make any sense, and I'm pretty sure Dirac has never written such a nonsensical formula ;-).

 

[Bob Dylan]

Thank you again for the reply. Was I mistaken then in thinking of rest mass as a fourth dimension?

 

[vanhees71]

Of course, how can a mass (dimension kg in the SI) be a fourth dimension of space (dimension metre in the SI)? It's simply not making the slightest sense! Where have you gotten this idea from?

 

[PeterDonis]

Dirac's rest mass seems to be expressed as a fourth dimension.

Where are you getting that from?