5 ms·
Note that speed is relative, but time dilation is not. That's the twin paradox, they're both relatively moving away from each other, but only one 'ages slower'.
by tux3 4y ago
Note that speed is relative, but time dilation is not. That's the twin paradox, they're both relatively moving away from each other, but only one 'ages slower'.
Though I don't know what it means to say a photon doesn't experience time, and even more so for hypothetical humans travelling at the speed of light. That's outside the scope of what relativity predicts.
- heavenlyblue 4y agoYou could also say “only one ages faster” so this is not a paradox because of that.
- misja111 4y agoOk so let's say two humans pass each other by somewhere in the universe, each in their own spaceship, in opposite directions. They both travel with half the speed of light, so relative to each other with full light speed. Which one is the one aging slower?
- ubercore 4y agoThey won't see each other moving at the speed of light though. This example is covered in any class on relativity. Having an approach velocity between two objects at the speed of light or greater is different than accelerating a frame of reference to c. When an approach velocity is c, nothing is actually _moving_ at c.
- Tyr42 4y agoIn particular, it's acceleration you need to account for when talking about time dilation, not speed. And acceleration is less symmetric.
- ryandvm 4y agoLove the Fermilab series of videos. Here's the one that covers the Twin Paradox: https://www.youtube.com/watch?v=GgvajuvSpF4 https://www.youtube.com/watch?v=GgvajuvSpF4