When astronauts head to Mars, they will experience time dilation. That's to be expected. In fact, your feet and your head experience time dilation, with your head aging ever so slightly faster than your feet. But how much time dilation will they experience (relative to Earth observers)?
First off, let's check we're all on the same page. Time passes at different rates for different observers, depending on their relative speeds, and their proximity to (and strength of) nearby gravitational fields. Time dilation is the difference between time elapsed on two clocks due to these causes, as described by special relativity and general relativity.
Gravity curves spacetime. The result is that the stronger gravity is near you, and the closer you are to the mass creating it, the slower time moves (from the standpoint of an observer, or whoever has the second clock. From your perspective, time ran at the usual speed). This is how your foot is younger than your old (relatively speaking) haggard head. READ MORE...
