Is it possible to travel to the past or the future? | Brian Cox

The Impossibility of Past Travel

• 💡 Brian Cox and Nalini agree that traveling to the past is impossible.
• 🧠 Stephen Hawking's chronology protection conjecture suggests that the laws of nature prohibit backward time travel to prevent paradoxes.
• ⚠️ Einstein's theory of relativity and the speed of light fundamentally prevent travel to the past due to spacetime geometry.

Theoretical Concepts and Dimensions

• 🧩 Mathematically, there are complex answers involving higher dimensions and symmetries that could theoretically allow time travel.
• 🌌 Wormholes are hypothetical shortcuts that could shorten distances, but their existence doesn't negate the fundamental physics preventing past travel.

The Reality of Future Travel

• ✅ Traveling to the future is possible and has been experimentally proven, although it requires significant scientific effort.
• ⏱️ Time dilation, a core concept of Einstein's theory, means that moving clocks run slower compared to stationary ones.
• 🚀 Protons in the LHC traveling at 99.9% the speed of light experience time 7,000 times slower than observers.
• 👨‍🚀 Astronauts returning from space have experienced time passing slightly slower, effectively traveling a tiny bit into the future compared to those on Earth.