  We propose that spontaneous folding and molecular evolution of biopolymers
are two universal aspects that must concur for life to happen. These aspects
are fundamentally related to the chemical composition of biopolymers and
crucially depend on the solvent in which they are embedded. We show that
molecular information theory and energy landscape theory allow us to explore
the limits that solvents impose on biopolymer existence. We consider 54
solvents, including water, alcohols, hydrocarbons, halogenated solvents,
aromatic solvents, and low molecular weight substances made up of elements
abundant in the universe, which may potentially take part in alternative
biochemistries. We find that along with water, there are many solvents for
which the liquid regime is compatible with biopolymer folding and evolution. We
present a ranking of the solvents in terms of biopolymer compatibility. Many of
these solvents have been found in molecular clouds or may be expected to occur
in extrasolar planets.
