I was eagerly waiting for this post. Thank you again @gogogadgetupvote for this great contest.
Do you know about The Twin Paradox ?
It is a thought experiment based on special relativity in physics which involves identical twins.
One of them makes a journey into space in a high speed vehicle (say a rocket). When he/she returns he/she can find the twin that stayed on earth has aged more.
This is because the physical and biological clock will run slower for the one that travelled in high speed.
Interesting ain't it?
I think that gravity also has something to do with the affect on the "biological clock". Stands to reason that in space with less gravity, vs. being on the planet under the full force of gravity would have an effect on that, as well. Definitely interesting and thought provoking! Third place!
Thanks!