The Search for Quantum Gravity

Physics faces a profound crisis as it struggles to unify two foundational theories: general relativity and quantum mechanics. While general relativity explains gravity and large-scale phenomena, quantum mechanics governs the microscopic world of particles. Despite their individual successes, these theories conflict, prompting the need for a unified framework known as quantum gravity.

One promising approach is string theory, which posits that particles are actually vibrating strings in up to 11 dimensions. However, its lack of testable predictions has spurred alternative ideas, such as loop quantum gravity. This theory envisions space and time as a network of minuscule loops, challenging the notion of time as a fundamental construct. Remarkably, loop quantum gravity suggests time might not exist at all.