Time is Relative

When an airplane passes by overhead in the distance sky, standing on the ground and looking up, it appears that the airplane is moving very fast...  and, that is confirmed mentally because we intuitively know that an airplane is faster than our cars, buses, and/or trains. 

BUT, if you are in the airplane looking down at a person looking up at you, it appears that the airplane is moving relatively slowly...

So, why is this and what has this got to do with time?

Think about it this way...
When our male astronauts went into space for several days their beards did not grow as fast as did the beards of the males on the ground working at NASA...

What that tells us is that time slows down the farther we move away from earth.  And, this can be understood easier if we look at a bicycle wheel.

Look at the wheel on the left...  and, imagine that the earth is that round black circle in the middle and that the edge of the universe is the black larger tire with the orange wheel. 

It it obvious (at least to me anyway) that the inner black circle makes several complete revolutions by the time the outer tire completes one complete revolution.

If the inner black circle's complete revolution represents 365 days, then it might make 10 complete revolution or 10 years by the time the outer tire makes one complete revolution or 1 year...

So, as one moves farther and farther away from the earth, time does not pass by as quickly as it does on earth.

Does that mean that astronauts could live longer is they remained in Outer Space?