Stellarator wrote:Source of the post This raises an interesting point as to the affects of time dilation, as I remember reading about that famous experiment involving the ISS astronaut Scott Kelly staying aboard the ISS for 520 days — all of which he spent zooming around Earth at 17,500 mph (28,160 km/h). When he came back do to Earth, he was 6 minutes and 5 milliseconds younger then his twin brother, Mark.
Space travel has a lot of complicated effects on the human body. But I do not think it is correct to say that he came back 6 minutes younger, and time dilation definitely cannot explain that. For spending 520 days in orbit, the time dilation would amount to him losing about 13 milliseconds compared to his twin. (-15 milliseconds from special relativity, and +2 milliseconds from general relativity.)
So he did come back literally younger, which would be measurable by an atomic clock (regular wristwatches are not accurate enough to measure a 13 millisecond difference out of a year), but not to any extent measurable by medical science. Whatever changes they found in his body had a different cause.
An'shur wrote:Source of the post I might have been overlooked
Sorry An'shur -- I didn't overlook it, but I don't know of the answer offhand. I may try to figure it out when I have the opportunity.