Time dilation is an effect from Einstein’s theory of relativity. It means that time can pass differently depending on where you are. Near a black hole, gravity is extremely strong. Because of this, time passes more slowly for someone close to the black hole than for someone who is far away. For example, imagine two astronauts. One stays far away from the black hole, and the other travels close to it. When they meet again, the astronaut who was near the black hole will have experienced less time. A few hours for them could be many years for the astronaut who stayed farther away. What is interesting is that the astronaut near the black hole would not feel anything unusual. Their watch would work normally, and everything would seem the same as always. Time only appears different when they compare it with someone who was farther away. The closer you get to a black hole, the stronger this effect becomes. This is why time dilation is one of the most interesting ideas in modern physics.
Music from Hans Zimmer from Interstellar
