Reasonable doubt: Cosmology's gift for physics

Abstract

This paper is about some of the ways in which the study of Cosmology has been key, both in initially developing, and in probing retroactively into, the foundations of modern physics. The past role of cosmological observations in triggering the development of mathematical physics, and modern science in general, is well known. But the present role of cosmological observations in possibly triggering a review of some never-challenged assumptions is playing out only presently, and so is not completely known yet. The cosmological observations cited in this paper concern the apparently universal pattern displayed by barred spiral galaxies. The typical barred spiral galaxy follows a common ‘body plan’ consisting of two spiral arms, acutely curved, and a central bar, not exactly straight. The arm curvature seems about the same for all such galaxies, and the bar wandering, if it is visible, is similar in initial slope to the arms. The several issues in physical theory that this so-common pattern invites us to acknowledge and investigate first arose in Electrodynamics. They then propagated into Quantum Mechanics and into Special Relativity Theory, and then into General Relativity Theory. Quantum Mechanics and Relativity Theory are the main pillars of twentieth century physics. So better clarifying the issues in Electrodynamics is important. If that elucidation comes to pass, Cosmology will have driven modern science, yet again, to a new level of understanding.