Comment on Know your place
ininewcrow@lemmy.ca 18 hours agoHere’s another perspective … this is local galactic group. Our nearest galactic neighbor is the Andromeda Galaxy … it’s located about 2 million light years from us. Again, if you could travel at the speed of light (which is impossible), it would still take you 2 million years to get there.
Another way of thinking of it is that the light we see from Andromeda today started it’s journey when our first prehistoric human ancestors first evolved in Africa 2 million years ago.
zout@fedia.io 16 hours ago
If you could travel at the speed of light, the only tim it would take you is the time spent speedign up and slowing down. Traveling at the speed of light stops the time for you.
ininewcrow@lemmy.ca 16 hours ago
It gets messed up really fast tho … so if you travelled at the speed of light 2 million light years to Andromeda and it only felt like a few minutes to you … then you travelled back 2 million light years back to our galaxy and it only felt like a few minutes to you … wouldn’t 4 million years have passed at your start point while you were gone?
zout@fedia.io 16 hours ago
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.