Biology usually defines life through traits such as organization, metabolism, information, or evolution. But Solaris puts those categories under strain. Could there be some form of active presence that does not fit the terrestrial pattern? Perhaps the problem is not whether there is life beyond Earth, but whether we would know how to recognize it.
Physics adds a suggestive opening here. Known life remains far from equilibrium thanks to energy flows, and this can be expressed, for example, by ΔG = ΔH − TΔS. Without available free energy, there is no sustained process. The continuous transformation of a system can also be thought of as P = dS/dt. These formulas do not prove that a planet is alive, but they do suggest that life might be, before being a concrete form, a persistent dynamic.
