Time Dilatation

The most important thing in the General theory of relativity, made by Albert Einstein, is that the time depends on space - with bigger velocity time goes slower. Even when velocity equals speed of light time stops.
For example russian astronaut who spent two years from his life for living in space and orbiting around the Earth saved 1/50 second of his life, because on orbit his velocity was very high. Or the center of the Earth is two and half years younger than surface, because points on surface goes faster than points in the center.
This discovery opens new capabilities in physics. Now we can easily exchange time for speed and speed for time. It will be useful in long space journeys in future. We can also make computer calculations faster. In one sentence: we can play with time.

Funny is if I'd move with my computer with speed equal 99,7% speed of light I'd finish this post before 4 o'clock.