Measuring Time and other Spatio-Temporal Quantities

Ordinary clocks do not measure time in the common and Newtonian sense, and there is a similar problem for spatial measurements due to effects of motion and gravitation. Einstein’s theories of relativity are based on the denial of the possibility of the ‘absolute’ measurements that would be required. Nevertheless, here it is shown how such measurements can be performed. For this purpose, a “light clock” (or equivalent) is linked with a “space-time odometer” that counts the zero crossings in the field of the cosmic microwave background radiation. The readings of these two instruments allow to calculate the time interval and the length of their path in Euclidean space even in the presence of local variations in gravitational potential.