The Death of the Proton

How the decay of one particle could lead to a theory of everything

Artist’s impression of a star approaching a black hole. Proton decay means a far future in which only black holes remain after everything else has crumbled and collapsed. Image by Nicole R. Fuller/National Science Foundation.

Three particles make up all familiar matter of the universe. From the murky brines of icy exoplanets to the ardent blue or red stars of distant galaxies, everything we see around us — on this world or on any other — is crafted from the same few ingredients. A single thread for every ornament on the tapestry of…