Part 4/9:
Efforts to formulate a single theory that encompasses both quantum mechanics and gravity have, so far, failed to produce a complete, consistent model. Einstein’s general relativity, which describes gravity as the curvature of spacetime, conflicts with quantum principles when energies become extremely high, such as near singularities in black holes. This incompatibility persists despite decades of research, making gravity the key outlier blocking the path to a unified theory.