I don't get time dilation/aging/relativity

No.11697295 ViewReplyOriginalReport
Like, I get how you can perceive time differently (the whole moving away from a clock at the speed of light thing) but isn't a second just a second???? I was watching interstellar and the scene where they were on the water planet and said that an hour on the planet was like a few years or whatever, how does that work??? isn't a year a year no matter if youre traveling at the speed of light or near a gravity well? isnt time constant??? Explain to me please /sci/ I'm not a scifag but i am interested in this