Trevor Pitts Former former CEO of an environmental remediation Corp. Chemist.
Roger Penrose was very puzzled by this question, essentially, how could the universe be at extremely low entropy at the beginning? The general feeling was that low entropy is some sort of inverse bank, allowing events to occur by increasing. I believe entropy is fundamentally misunderstood. It is not a driving force, it is a measurement. The universe is expanding in spacial size, like raisin bread, the raisins get further apart, and the farther they are apart, the faster they separate as the dough rises, ie it expands evenly throughout. The Hubble expansion is not like a hand grenade, blowing outward, leaving an expanding void as the shrapnel flies away from the explosion. The universe also gets older. Space and time are inseparable, spacetime expands. What we call entropy is fundamentally dilution.
Mass gets further apart and energy density falls. This is the redshift, light and other electromagnetic waves increase in wavelength. The intense light released when the temperature of the universe fell enough to form ordinary matter from plasma, so that space became transparent, was stretched until it became the cosmic background radiation. If the universe were not expanding, no complex events could occur, because no heat sink would exist. Why? Olber’s Paradox, an example of how scientists can believe the impossible.
Olber’s paradox is quite simple. Light fades as the square of the distance, the inverse square law. But light sources, stars, increase with the volume, ie the cube of the distance. So if the universe were static, no matter how huge, eventually the temperature of every point would rise to be the average temperature of the surface of stars. The sky would be purplish white, at 10,000 degrees K at least, not the current 3 degrees K. Obviously this had not happened, yet everyone, including Einstein, thought it was static, until Hubble proved otherwise. The expansion of spacetime IS time. Increasing entropy does not drive the arrow of time, it is the other way round. The only means allowing heat engines to work is the great, cold, expanding vacuum acting as the ultimate heat sink. Every activity we indulge in from metabolism to rocketry, ends in heat, which must diffuse and then radiate into space. Gravity appears to be too weak to slow or reverse the expansion. Time’s arrow is simply outward, expanding everywhere, like space and with space. To talk of the entropy of the universe is simply to talk of its age.
Physicists will still quibble that time is not symmetric, but I proposed an answer to that, in 1999. This is to propose time symmetry via another universe on the other side of the big bang, where time expands outward in negative time from the origin, which is in the center of time. According to Feynman the matter there would be antimatter to us and vice versa for them. Nobody is “before” the big bang and yet both us and the antipeople are “after” it in terms of time’s arrow. The distinction does not exist.
Details and references are at:https://fundamentalstudies.org/