The derivative of time in the spacetime* tensor is just 1. There's no speed up, locally, which is what counts. The rest is just an effect of observation. *I do

The derivative of time in the spacetime* tensor is just 1. There's no speed up, locally, which is what counts. The rest is just an effect of observation. *I do not remember nor care what it's called. I'm sure you know what I mean anyway.