Two empiricisms impose constraints. First, most authors converge on a Proterozoic Earth radius about half the present radius. Second, rate of expansion has increased exponentially, with most rapid expansion in most recent times. More than one cause may co-operate, but the exponential rate-increase eliminates as main cause meteoritic accretion, which would diminish exponentially with time.
Phase change at constant mass is eliminated as main cause because the surface gravity force would have been unacceptably high with the Proterozoic (or even Palaeozoic) diameter. This is a problem shared by the whole Universe, because regression of Hubble dispersion would concentrate the whole mass of the Universe into a small space, billions of times more massive than a black hole, whence nothing could ever have escaped. Earth and Universe demand the same answer ? mass must increase exponentially with time, at a rate which must increase exponentially with time, with a significant exponent so that small bodies wax imperceptably slowly whereas centres of galaxies appear (as Jeans has remarked) like singular points where matter is "created" at high rates. Empiricism also suggests a modulating term with the primary exponential expression to add a pulsation,
Creation has no place in physics, yet all physics rests ultimately on creation, which however is outside the laws of physics. This dilemma vanishes if the sum of all matter, energy, momentun and charge is zero ? a universal null. Creation vanishes as a problem, because everything in the Universe has its equal and opposite, gemini which appear together, and mutually cancel. Indeed, it could not be otherwise!
It is easy to contemplate that all positive and negative charge cancels, and that all momentum cancels. But it is less obvious that matter is the antithesis of energy, like the obverse and reverse of a coin ? impossible of independent existence. The instant that new matter of mass m appears in the Universe, the potential energy of the whole universe increases by mc2, like increasing our assets by increasing our debt. We could call matter and energy positive and negative and write E=-mc2, which would be no more nor less correct. than, our convention of positive and negative charge, or writing + and - for N and S poles, or up and down. Putting energy negative with respect to matter seems to be contradicted by the release of nuclear energy with loss of mass. But this energy is only configurational energy of such very large or very small nuclei, which can be released by fission or fusion with loss of mass. But no such energy is available from iron or other atoms in the middle of the range, towards which both ends converge.
The inertial mass of any body equals the potential energy of the Universe in its field. As Mach, and later Einstein, observed, there can be no inertia against space, only against other matter. Universal mass and universal energy both commenced from zero at T0 (at minus infinity?) and have increased pari passu, The dilemma of creation vanishes, and with it Aristotle's problem of the unique initial term or uncaused cause. Physics is made whole, with no unique initial state outside its laws.
