Sam's Believe It Or Not! Galactic Wonders Part 4
Speed of Light & Relativity 🚀 Light travels at 299,792 km/s—fast enough to circle Earth 7.5 times in just one second! A light-year (9.46 trillion km) is the distance light travels in a year, letting astronomers map the universe using time itself. According to Einstein’s relativity, as you approach... Sign in to see full entry.