Alcohol constrains physical constant in the early universe
(Phys.org)—Radio-astronomical observations of a distant galaxy indicate that the ratio of the proton's mass to that of the electron has hardly changed over cosmic history. This fundamental constant of nature has changed by 10-7 or less, equivalent to a maximum of one hundred thousandth of a percent, in the past 7 billion years. Scientists from VU University Amsterdam and the Max-Planck-Institut für Radioastronomie (MPIfR) used the Effelsberg 100-m radio telescope to obtain accurate measurements of methanol absorption at several characteristic frequencies. Methanol, the simplest form of the family of alcohol molecules, was observed in a distant galaxy at redshift z = 0.89 toward the quasar system PKS 1830-211. The resulting stringent limit on the proton-to-electron mass ratio shows that molecules and molecular matter are, with high accuracy, the same now as 7 billion years ago. The work is published online in Science Express on 13 Dec. 2012.