What does Einstein's theory of relativity say about time and space?
We like to think of time as a steady drumbeat — tick, tick, tick — the same for everyone, everywhere. And space as a giant unmoving box we all live inside. Comfortable, right? Well, plot twist. About a hundred years ago, a daydreaming young man named Einstein looked very closely at light, and discovered that time and space are nothing like that. They bend. They stretch. They keep secrets.
It all starts with one stubborn fact about light. No matter how fast you chase a light beam, it always zooms away from you at the exact same speed. Run toward it, run away from it — doesn't matter. Light just shrugs and travels at one fixed speed, always. That sounds harmless. It is not. To keep light's speed the same for everyone, the universe has to bend something else instead — and the only things left to bend are time and space.
