A light year is a unit of distance, not time, but it's a measure that's hard to wrap your head around. It's the distance light travels in one year, which is about 9.46 trillion kilometers. To put that into perspective, the nearest star to the Sun, Proxima Centauri, is about 4.24 light years away. That's a staggering distance that makes our own solar system look tiny in comparison.But what's even m...More