- #1
Frank Castle
- 580
- 23
As I understand it, since space-time is modeled as a four dimensional manifold it is natural to consider 4 vectors to describe physical quantities that have a direction associated with them, since we require that physics should be independent of inertial frame and so we should describe it in terms of objects that are invariant under Lorentz transformations.
Having said this, I'm slightly unsure as to why certain quantities that are scalars in classical mechanics are no longer scalars in the context of special relativity? For example, what is the reason why energy is not Lorentz invariant (I get that it is combined with 3 momentum to construct a 4 momentum vector, but I don't really understand why)?
Having said this, I'm slightly unsure as to why certain quantities that are scalars in classical mechanics are no longer scalars in the context of special relativity? For example, what is the reason why energy is not Lorentz invariant (I get that it is combined with 3 momentum to construct a 4 momentum vector, but I don't really understand why)?