A story about space travel from which astronauts come back to the grown old friends the same young people do not excite creation any more as many years ago. However and today the question of a current of time on Earth and in space is clear not to everyone.
Whether young people can return from space
For a start it is necessary to clear up in the concepts "time" and "ageing speed". Time per se – the concept which is thought up by the person. Counting of seconds an arrow, days, months and years – all this the person uses for own convenience. But time in itself – a concept abstract. If to speak about a current of time, then it is identical everywhere: in space, on Earth or on any other planet of the Solar system. In the same way there will be processes of cell aging and a human body.
From where did the theory that in space the people do not grow old undertake? Everything is simple. Let's address the theory of relativity. Time really does not depend on location, but can depend on the speed with which you move. At a speed of the ship exceeding the speed of light, time on it will really begin to flow more slowly in relation to time, for example, on Earth. Astronauts of a difference will not notice – in their reference system everything stable: time and space pass with a former speed. It as the train which rushes by the platform: in the car the passengers quietly have tea and play cards, and people at the station can hardly distinguish their silhouettes – so quickly they rush by.
Delay of time
The theory of relativity has one more curious aspect concerning a current of time on Earth and in space. According to it, gravitation of our planet has some impact on the speed of a current of time. Than gravitation is more, the more the curvature of space time in this point, and the more slowly flows time concerning the observer who is far from the massive body creating this curvature.
According to this theory, far from our planet time will pass slightly quicker. Can seem that the theory of relativity in this point contradicts itself, but you do not hurry with conclusions. The fact is that change of speed of a current of time so insignificant that it can easily be neglected. The most ultraprecise hours in the point of space remote from our planet, because of this effect will show time with a difference 45900 nanoseconds/day faster than, just the same hours determined on Earth.