My Retirement Plan At 35

[momoeagle]

hi momoeagle,
side-chat about physics since u said u specilaise in that, is it true that a returning astronaut from outer space is actually living behind earth time?

This is from H3 physics which I don't teach, but is part of junior physics olympiad which I teach :p

From the Special Theory of Relativity by Einstein, objects in a faster moving frame would experience something called time dilation. That means, time travels slower relative to us. To put it simpler, if we on Earth are considered as a stationary frame, the astronaut in orbit will be considered as in a moving frame. In time dilation, 1 second to the astronaut is probably 1.5 or more seconds to us on Earth, so yes, in fact, the astronaut having aged a day in orbit would be equivalent to us aging more than a day on Earth.

However, such theory applies mainly when they are travelling at speeds near to the speed of light, termed as c. If we calculate the orbital velocity of the astronaut, it's only at 3000 m/s (0.00001c), which is far from the speed of light (velocity on earth's surface is 480 m/s)

Being so far away from the speed of light, while astronauts in orbit may age slower, the difference, if any, will be insignificant.