Einstein's famous equation looks so simple, but calculating the actual speed of light? That required a tome of epic proportions. Ole Rømer was the first to prove light wasn't instantaneous in 1676, measuring Jupiter's moon eclipses to calculate that light moves at a finite speed. Modern physicists just write "c = 299,792,458 m/s" on the board like it's nothing, conveniently forgetting the centuries of astronomical observations, experimental failures, and mathematical headaches that went into that number. Science in a nutshell: centuries of painstaking work condensed into one elegant formula that undergrads memorize the night before an exam.