Time dilation is a concept that stems from Einstein's Theory of Relativity.
Some of us have heard or know about it already, for those who haven't, here's what it means- due to differences in the gravitational field in different regions of the universe time tends to flow differently. It flows slower for regions of space having a strong gravitational field and faster in other places.
Just like in the movie Interstellar.
On Miller's Planet - Cooper, Brand and Doyle go in search for Dr. Miller and her probe and had to experience time dilation of a severe magnitude because of being in a very strong gravitational field, that of Gargantua, a super massive blackhole.