A major outstanding challenge is to connect experimental observables—which are often indirectly related to membrane structure—with a microscopic model of the membrane. Over the microsecond timescale of a conventional molecular dynamics simulation a lipid explores roughly 1 nm2 of membrane area. In order to study immiscible liquid bilayer phases in the computer, which demands observation of lipid dynamics on at least 10 microsecond timescales for typical simulation lengthscales, we have been awarded a grant of time on the Anton machine. Anton is a special purpose supercomputer designed and built for molecular dynamics calculations by D.E. Shaw Research and housed and maintained by the Pittsburgh Supercomputer. Our calculations aim to uncover the experimental signatures of liquid-liquid phase separation in ternary bilayer mixtures.