Like Hermann Weyl and Arthur Eddington before, Paul Dirac also noticed that the ratio between the dimensions of the universe (visible size and age) and the protons (diameter, duration of the passage of light through the proton) constitutes a large number of about 10^40. And that the ratio of the gravitational force and the electromagnetic force between an electron and a proton is roughly the same. From this he deduced a time-variation of at least one fundamental "constant" (he preferred the gravitational constant for this). He could only make a rough estimate, because of course he did not yet know the more precise value of 13.8 billion years world age assumed today. Especially the evaluation of the data from the Planck space telescope has produced this value in the last 10 years. So today we are in a position for a more detailed evaluation. We will show that gravity could result from an universal time-energy uncertainty relation if we assume that the universe's age is 13.8 billion years. We will give by this approach a precise and straightforward formula for the gravitational constant G without magic factors, powers or roots. Furthermore there has been a lot of guesswork in recent years about the size of the proton radius. It was triggered in 2010 by the measurements at the Swiss Paul Scherrer Institute, which measured approx. 0.84 femtometers, a radius value that is around 4 percent smaller than the independent measurements previously made. But in the meantime, this smaller value has been confirmed by several other independent measurements and is now considered the more accepted value. We are sure that the value of 0.84 femtometers will soon be rid of any last doubts. Because in a finite-time universe there can be no frequencies smaller than the reciprocal of the universe age Tu and accordingly all energy values in the universe must be an integer multiple of h/(2pi*T(u)). Thus all electromagnetic energy amounts must be rounded down by half of this value on average. We will show that for a proton radius of 0.84 femtometers, that energy value rounding is exactly in the same ratio as the gravitational force between proton and electron. So we will derive a simple equation for the proton radius from other fundamental constants. And we will show that the ratio between the Hubble radius and the proton radius is obviously a constant that gives the appearance of being invariant in time.