THE LOCATION PRINCIPLE

The Greeks developed the “two-sphere” universe that endured for 2000 years and consisted of a spherical Earth surrounded by a distant spherical surface (the sphere of stars) studded with celestial points of light. This geocentric picture was finally overthrown by the Copernican revolution in the sixteenth century and replaced by the heliocentric picture with the Sun at the center of the cosmos. The sphere of stars remained intact. But revolutions, once begun, do not readily stop, and by the seventeenth century the heliocentric picture had also been overthrown. Out of the turmoil of the revolution emerged an infinite and centerless universe that ever since has had a checkered history. In the eighteenth century the idea arose of a hierarchical universe of many centers, and in the nineteenth came the idea of a one-island universe – the Galaxy – in which the Sun had central location. Once again, in the twentieth century, we have the centerless universe.