Actually, while mathematically heavy, it’s easy to measure in GR, assuming you’ve got a metric solved (If you don’t, you’re fucked. That shit is intractable to the point where you can name every exact solution on one page, and inexact solutions can just be lies) However, you may have to ask additional questions about what sort of time you want, which probably stems from why you need it.
Or anyone who has worked with general relativity
Actually, while mathematically heavy, it’s easy to measure in GR, assuming you’ve got a metric solved (If you don’t, you’re fucked. That shit is intractable to the point where you can name every exact solution on one page, and inexact solutions can just be lies) However, you may have to ask additional questions about what sort of time you want, which probably stems from why you need it.