Fine-Tuning Is a Problem in Physics

If the first billionaire is worth an amount A, and the second is worth an amount B, then the difference between them is C, where A – B = C. Without any further knowledge, you should be able to assume something about C: it shouldn’t be much smaller than either A or B. The expanding Universe is basically a race between these two competing forces:

the initial expansion rate, which works to drive everything apart,

and the gravitation of all the different forms of energy present, which works to pull everything back together,

with the Big Bang serving as the starting gun. If we extrapolate back to the earliest stages of the hot Big Bang based on our modern observations, we learn that the initial expansion rate and the initial energy density must be balanced to something like 50 significant digits.

Source: www.forbes.com