gravitational time dialation

In simple terms, gravitational time dialation refers to the effect gravity has on the passage of time. Clocks that are closer to a source of a strong gravitational field (such as a planet) run slower than clocks further away from the gravitational field. For example, scientists have demonstrated an atomic clock located in the International Space Station runs at a slightly faster pace (a matter of nanoseconds) than an atomic clock located on the earth.