As a result of the misinformation concerning entropy I have seen the most extraordinary ignorance loudly trumpeted on the internet by otherwise highly educated people.. Recently I pointed out to a well known TV Physicist one fundamental problem with the Big-Bang is it produces just a very big ball of slowly cooling H2 with some He. How can that form a star.?
The question was put; How is it that the product of the Big Bang, (a cool ball of H2), being high entropy (highly disordered) is theorized to self compress under its own gravity to become the first star or galaxy (low entropy) without violating the Second Law? The Second Law says that the total entropy of the universe will always increase and we are talking about the whole universe. He did not disagree with the premise and passed the question on to a more knowledgeable authority.. who passed it to another authority.. who diverted the whole discussion into entropy of black holes..!
So how is the star being a high concentration of mass and energy at high temperature more 'ordered' than the cooler ball of H2? Isn't the star a boiling mass of high energy atoms also very disordered and perhaps more so than the cooler huge diameter ball of H2 where the atoms have slowed down. Have I got these terms mixed up?
In my former example of a box with one side hot and the other cold I showed a calculation based on the heat flow from hot to the cold in that closed system. The heat flow into the cold side (+ve) always gives a greater entropy increase than the entropy decrease of the hot side (-ve) because T is lower and thus dQ/T will always be greater. Does not this mean the hot side is going from high entropy to lower entropy the very reverse of the point in my question.
The mistake is to think of the hot side/object in isolation and not the whole box or this case the whole universe. The calculation is for the whole system.. hot body AND its surroundings. It is a calculation of the total system going from an initial state where energy is concentrated in part of the system and naturally starts to spread itself out more evenly. It is the SYSTEM that is low entropy (ordered).
So for the Big Bang universe after expanding to a huge ball of H2 at lower temperature what happens under self gravity.. David Wallace published his calculation in 2009 saying..
"on this model even a cloud which begins at absolute zero will only contract to about half its initial radius before reaching its maximum entropy state"
That is a real problem..
