Why Time Travel Will NEVER Exist | Brian Cox

Why Time Travel Will NEVER Exist | Brian Cox

You've already time traveled today. By the time you finish listening to this sentence, you'll have moved forward in time by several seconds. That's not a metaphor. That's physics. We're all time travelers, moving relentlessly into the future at a rate of one second per second. It's inescapable. It's universal. And it's completely useless for what people actually mean when they talk about time travel.

When we imagine time travel, we imagine something far more dramatic. Stepping into a machine and emerging in ancient Rome. Visiting the dinosaurs. Preventing disasters before they happen. Meeting our younger selves. Going back to fix mistakes, to change decisions, to rewrite history. This is the time travel of science fiction, the time travel that has captivated human imagination for over a century since H.G. Wells published The Time Machine in 1895.

And this kind of time travel, travel backward through time, is almost certainly impossible. Not just difficult. Not just beyond our current technology. But forbidden by the fundamental structure of the universe itself.

To understand why, we need to understand what time actually is. Not time as we experience it, that flowing river carrying us from past to future. But time as physics describes it, as Einstein revealed it over a century ago. Because time is far stranger than our intuitions suggest, and those strange properties are precisely what make backward time travel impossible.