In the physical sciences, a state of matter is one of the many ways that matter can interact with itself to form a macroscopic, homogenous phase. The most familiar states of matter are solids, liquids, and gases. However, the most common state of matter in the visible universe is plasma. Less familiar phases include: quark-gluon plasma; Rydberg matter; Bose-Einstein condensates and fermionic condensates; quantum spin Hall state; degenerate matter; strange matter; superfluids and supersolids; and possibly string-net liquids.