For Newton, the time interval between two physical events dt is also absolute, or as he put it absolute and mathematical time, of itself, and from

For Newton, the time interval between two physical events dt is also absolute, or as he put it absolute and mathematical time, of itself, and from its own nature, flows equably without relation to anything external, and by another name is called duration. That remains the same with respect to all observers (a Lorentz invariant) who differ in state of motion by a constant vector velocity. Two observers in motion relative to one another (especially close to the speed of light) who measure events to be separated in space and time may differ in the individual values of d!2 and dt 2 , but not in ds 2 . Einsteins theory of general relativity adds the ideas that gravitation might curve space and warp time. What do we mean by that?