"Light Speed" :
If I could travel as fast as light, then travelling to a planet on any star, would seem to me instantaneous. Like I had a blink, and the next moment I opened my eyes to find myself on a new planet some 20 light years away.
But reaching there I would also observe that 20 years have passed on that planet after that single blink. And in that time people on earth have been watching me traveling for 20 years to reach it.
Finally follows a page that shows how frustratingly slow "light speed" actually is. [ it doesn't explain what I wrote above ]
https://www.businessinsider.com/how-fast-speed-light-travels-earth-moon-mars-nasa-2019-1?