tive preceded that moment, which would render the creation moment merely a transition between eras—from negative to positive mass—rather than an abrupt singularity. In other words, the bang would become a blur.

Whether or not the effects of changing mass could be detected through experimentation depends on the rate of growth. The slower the increase, the less noticeable the effect. Therefore, in the limit in which mass changes by an infinitesimal amount, the five-dimensional theory would reproduce known results for standard four-dimensional relativity. There would be no detectable difference between the two theories. If, say, the rate of increase were approximately seven-billionth of a percent per year, the effect still couldn’t be measured in the laboratory. Nevertheless, over the 13.7-billion-year history of the observable universe, it would amount to an increase of 100 percent in each particle—that is, from masses of zero to their current values. This dramatic increase could potentially be detected through astronomical measures.

The idea of changing mass offers an intriguing solution to several of the conceptual problems that plague conventional cosmology. Mass is not created in a sudden “big bang” singularity. Rather, it grows naturally with time, much like the familiar Hubble expansion. To prove this conjecture, however, would require new and delicate tests.


If the solidity of mass is a phantom, a consequence of the viewing of five-dimensional geometry through four-dimensional spectacles, could the passage of time be an illusion as well? A number of thinkers, including Fred Hoyle, J. G. Ballard, Arthur Eddington, Julian Barbour, David Deutsch, and even Einstein, have suggested that time as we know it is purely an ordering device and that the real universe is in some fundamental sense timeless.

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