Yup, but it’s not felt like, it’s how much time really passed for you.
Another one I’ve always liked; suppose two people (or space ships, whatever) are together in the empty space between galaxies. One of you gets a boost from an external actor, and travels 10 lightyears away at the speed of light. After that, the other one gets the same boost and joins the first. So for both, ten years have passed. But, without an external reference, there is no way to know which one moved first.
Yup, but it’s not felt like, it’s how much time really passed for you.
Another one I’ve always liked; suppose two people (or space ships, whatever) are together in the empty space between galaxies. One of you gets a boost from an external actor, and travels 10 lightyears away at the speed of light. After that, the other one gets the same boost and joins the first. So for both, ten years have passed. But, without an external reference, there is no way to know which one moved first.