List of unsolved problems in physics

The following is a list of notable unsolved problems grouped into broad areas of physics. Some of the major unsolved problems in physics are theoretical, meaning that existing theories are currently unable to explain certain observed phenomena or experimental results. Others are experimental, involving challenges in creating experiments to test proposed theories or to investigate specific phenomena in greater detail.

Extends: [Lists of unsolved problems](https://wikipedia.org.ai/Lists of unsolved problems), [Physics-related lists](https://wikipedia.org.ai/Physics-related lists), [Unsolved problems in physics](https://wikipedia.org.ai/Unsolved problems in physics)