List of unsolved problems in physics
1 Unsolved problems by subfield
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