What if time and length are no longer absolutes? You’ve got your digital watch on your wrist and a ruler on your desk. These seem like absolutes: a second and a centrimetre for you must be the same as they are for me, and the same as they are on Alpha Centauri. But maybe they’re not. If I stay on my balcony while you start flying round the galaxy at an incredible speed, and if you could later whiz past my balcony so that we could somehow compare watches and rulers, my theory is your ruler would be smaller and your watch would be going slower than mine. It wouldn't seem different to you but I think the speed would make it different the weird thing is if a person went really fast around the earth and came back they'd have aged differently than someone on Earth and I don't have the math done yet but it would explain some of the strange stuff we observe about light appearing to be the same speed even if we are going closer or farther away from the source of it.
If someone wants to help with the math that would be really great because I think of stuff and then don't always know the best math to use when figuring it out.