dylanduck writes "Cosmologists have begun thinking that yet another fundamental constant of nature is, er, not constant. The constant in question is the ratio of a proton's mass to that of an electron. It governs the strong nuclear force but there's no explanation for why that ratio should be constant. If true it would provide support for string theory, which predicts extra spatial dimensions." From the article: "Researchers at the Free University in Amsterdam in the Netherlands and the European Southern Observatory in Chile discovered the variation in mu. They did it by comparing the spectrum of molecular hydrogen gas in the laboratory to what it was in quasars 12 billion light years away. The spectrum depends on the relative masses of protons and electrons in the molecule."