How does Albert Einstein's theory of time help us today?

Answer 1

Albert Einstein's Special Theory of Relativity says many things. Among them is that, when an object is moving relative to an observer, the time line of the object is different than that of the observer.

This has been proved. Two atomic clocks were calibrated and checked. One was placed on an aircraft and flown around the world. When it returned, it was different than the first. Then it was flown around the world in the opposite direction. When it came back, it matched to first one.

Here's another one, in the theoretical realm... If a spaceman were to travel to Alpha Centari (our nearest star, 4 lightyears away), and then travel back, at a speed very nearly equal to the speed of light, the spaceman would seem to note that the round trip only took minutes, while an observer on Earth would note that the round trip took 8 years!!! This ignores the issue of mass and energy required to do so, of course.

In real terms, one example from today is that the orbiting GPS satellites have their master clock offset by a very small but measureable amount, in order to compensate for the dilution of time (as its called) due to their high velocity around the Earth.