Black holes and the Big Bang - where physics breaks down and quantum gravity must provide new insights into the nature of spacetime.
Singularities are places where our current understanding of physics breaks down completely. They represent points or regions where quantities like density, temperature, or the curvature of spacetime become infinite - clearly unphysical results that signal the limits of our theories.
The two most famous singularities are at the center of black holes and at the beginning of the universe in the Big Bang. In both cases, general relativity predicts that matter gets compressed to infinite density in zero volume - a mathematical impossibility that suggests we need new physics to understand what really happens.
Quantum gravity offers hope for resolving these singularities. Just as quantum mechanics prevents atoms from collapsing by introducing a fundamental uncertainty, quantum effects might prevent the formation of true singularities by introducing quantum "bounce" mechanisms or other exotic phenomena that halt the collapse before infinite densities are reached.
The two fundamental singularities: black hole centers and the Big Bang