General Relativity treats spacetime as a smooth, continuous fabric. Quantum physics suggests that at the smallest scales (the Planck scale , about 10-3510 to the negative 35 power meters), everything should be "chunky" or quantized.
The difficulty lies in how each theory views the stage of the universe:
Which of these theories—the "strings" of energy or the "loops" of space—do you find more ? Foundations of Quantum Gravity
Proposes that everything in the universe is made of tiny, vibrating strings of energy. It requires extra dimensions of space that we cannot see.
Foundations of Quantum Gravity: Bridging the Immense and the Infinitesimal General Relativity treats spacetime as a smooth, continuous
While no single theory is yet proven, several major contenders offer different "foundations":
Modern physics rests on two pillars that refuse to support the same roof. On one side, explains the universe at the largest scales—planets, stars, and the curving of spacetime. On the other, Quantum Mechanics governs the subatomic world where particles exist in clouds of probability. A theory of Quantum Gravity is the "Holy Grail" intended to unify these frameworks into a single, cohesive description of reality. The Core Conflict: Why Unification is Hard Proposes that everything in the universe is made
Our current laws of physics fail at the very first moment of the universe. Quantum gravity could explain how the "cosmic egg" actually hatched.