Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

by Steven Weinberg

The fact that the laws of nature seem to distinguish between stationary and rotating frames of reference bothered Isaac Newton and continued to trouble physicists in the following centuries. In the 1880s the Viennese physicist and philosopher Ernst Mach pointed the way toward a possible reinterpretation. Mach emphasized that there was something else besides centrifugal force that distinguishes the rotating merry-go-round and more conventional laboratories. From the point of view of an astronomer on the merry-go-round, the sun, stars, galaxies—indeed, the bulk of the matter of the universe—seems to be revolving around the zenith. You or I would say that this is because the merry-go-round is rotating, but an astronomer who grew up on the merry-go-round and naturally uses it as his frame of reference would insist that it is the rest of the universe that is spinning around him. Mach asked whether there was any way that this great apparent circulation of matter could be held responsible for centrifugal force. If so, then the laws of nature discovered on the merry-go-round might actually be the same as those found in more conventional laboratories; the apparent difference would simply arise from the different environment seen by observers in their different laboratories.