The claim that the young universe was in a low-entropy state seems at odds with
I've looked at some other answers and they're too technical for me, but I think I've understood the reason to be basically this:
"Entropy was lower because the universe was smaller."
Is this right?
Is this right?
No. I think you've arrived at this because you're not considering the gravitational degrees of freedom. Sheldon Goldstein puts it this way:
[T]he attractive nature of the gravitational interaction is such that gravitating matter tends to clump, clumped states having larger entropy. . . . For an ordinary gas, increasing entropy tends to make the distribution more uniform. For a system of gravitating bodies the reverse is true. High entropy is achieved by gravitational clumping — and the highest of all, by collapse to a black hole.
So, gravitationally speaking, the young universe had very low entropy because the distribution of mass-energy was nearly uniform rather than clumped.
Now, the question of why this was the case is much more difficult to answer.
At the beginning there was a single waveform expanding to the present , very high temperature /energy, and no space ie. one single wave state- low entrophy.
