Chapter 5, The Need for a New Theory, General Relativity vs. Quantum Mechanics Summary and Analysis

Since quantum mechanics governs the very small, and general relativity the very large, in most situations one uses either one theory or the other, but not both. However, in some situations—like the central point of a black hole which is both very small and very massive—both theories are needed. However, when combined, the theories are completely incompatible. Quantum mechanics states that, on a microscopic level, energy and momentum are uncertain: they are constantly fluctuating, borrowing, and creating energy, though on average it all cancels each other out, leaving empty space looking serene. This is the major problem in uniting quantum mechanics and general relativity. To attempt solving this problem, physicists developed quantum electrodynamics, and ultimately...