Carlo Rovelli: Why Time Doesn't Exist in Fundamental Physics

The Relativity of Time

• ⏳ Time is not uniform; it passes slower at lower altitudes and faster at higher ones.
• 🌌 Near black holes, time slows dramatically, effectively stopping at the event horizon due to extreme gravitational forces.
• 💡 Einstein's theory predicted this phenomenon of time dilation long before direct observation.

Exploring the Infinitesimal

• 🔬 Physics delves into the microscopic structure of reality, examining scales far beyond atoms and DNA.
• 🧩 At its most fundamental level, space is not smooth but is fractured into tiny "loops", a concept central to loop quantum gravity.

Time's Absence in Fundamental Equations

• 📝 The equations of loop quantum gravity, which describe the universe at its smallest scales, remarkably do not contain a time variable.
• 🔑 This suggests that time is not a fundamental component of the universe's ultimate structure, unlike our everyday perception.

Time as a Human Approximation

• 👁️ Humans do not directly perceive time; instead, we observe the relative movement of objects, such as the swinging of pendulums or the sun's position.
• ⏱️ The concept of a universal, flowing time is a useful approximation for daily life but proves inaccurate for precise descriptions in fundamental physics.

A Relational Universe

• 💃 Rather than a single universal rhythm, the universe is better understood as an infinite dance of independent elements, each with its own unique pace.
• 🧭 Just as "up" and "down" are relative to Earth, the concepts of "before" and "after" are relative constructs that disappear in a more fundamental description of the cosmos.
• 🌱 Science continuously challenges our "provincial" views of the world, pushing us to embrace a more accurate and less anthropocentric understanding of reality.