This never made any sense to me whatsoever.
I’ve see all the physicists (Michio Kaku, Stephen Hawking, Neil DeGrasse Tyson, etc.) explain this principle but it doesn’t make sense. They say that if you were to go to the moon and back at a certain speed near the speed of light, you might return to Earth a thousand years into the future like what happened in Planet of the Apes. But if you were going at the speed of light, you would arrive at the time light takes to arrive there. Why the dip? What is being missed?
It doesn’t help that media often portrays this incorrectly. Take the movie Lightyear, for example. Sure, it’s a sci fi movie for kids so it doesn’t have to be scientifically accurate, but the way they portray it is completely nonsensical. They show Buzz Lightyear trying to reach light speed in his space ship. Each time he flies around the sun, he goes faster, but more time has passed on the planet he left by the time he gets back. In reality, the faster you go, the less time it takes you to get somewhere (from some external reference of time). It’s just your experience of time that changes.
Interstellar is at least a little bit closer (ignoring the whole time travel part)