How I Can Become Younger Than My Grandson

Time is relative to your frame of reference and if you leave that frame of reference, then it is relative to the frame you are in. If you go into space and you have a watch and calendar to tell time and someone on the earth also has a watch and calendar to tell time, the time keeping will be different as long as there is relative motion between you and the person on earth. Now suppose I am 80 years old and my grandson who remains on the earth is 10 years old and I get into a space ship to travel at 186,291 miles per second, then the relative time between earth time and space time is 100. I travel at this rate for one year then return to earth to my grandson, my age is 80 + 1 = 81 years. My grandson’s age is 10 + 100 = 110 years.

When I am on earth with my grandson the passage of time is the same for both of us. This difference in time for an observer on earth and one in a space vehicle has been accepted universally. This particular case just emphasizes the difference.

At the present time our maximum speed is about 10 miles per second, so on our graph of relative velocities, that is S/C, one could see that this speed is much less than 0.1, so the curve is essentially still on the horizontal axis. The actual value is (10)/(186,300) = .000054.

If one takes the speed we were making in 1850 which is about 40 miles per hour then take our top speed today which is 18,000 miles per hour, then in 150 years our speed has increased by a factor of 450. From that rate of increase we would be traveling at 18,000 times 450 = 8,100,000 miles per hour or 2,250 miles per second in the year 2150. Now (2,250)/(186,300) = .012, which is still very low on our graph.