List of unsolved problems in physics

1 Unsolved problems by subfield

1.1 General physics/quantum physics

1.2 Cosmology and general relativity

1.3 Quantum gravity

1.4 High-energy physics/particle physics

1.5 Astronomy and astrophysics

1.6 Nuclear physics

1.7 Atomic, molecular and optical physics

1.8 Classical mechanics

1.9 Condensed matter physics

1.10 Plasma physics

1.11 Biophysics

2 Problems solved in recent decades