@dr.topazA photon crossing the entire universe would experience that trip as instant. From our side of things, watching it move, we'd clock billions of years passing by. That gap is what Einstein's theory of relativity forces us to sit with. The mechanics: as any object gets closer to the speed of light, time for that object runs slower compared to someone watching from outside. The effect has a name, time dilation. Push all the way to light speed and the elapsed time drops to zero. Physicists walk through this to show how much relativity changes the way we think about time itself. Weird to hold both versions at once, but there it is

@dr.topazA photon crossing the entire universe would experience that trip as instant. From our side of things, watching it move, we'd clock billions of years passing by. That gap is what Einstein's theory of relativity forces us to sit with. The mechanics: as any object gets closer to the speed of light, time for that object runs slower compared to someone watching from outside. The effect has a name, time dilation. Push all the way to light speed and the elapsed time drops to zero. Physicists walk through this to show how much relativity changes the way we think about time itself. Weird to hold both versions at once, but there it is