Re: Does an expanding universe violate the Second Law of Thermodynamics?

Steve,
     There are two flaws in your argument.  The first is in your 
mathematics.  If S=H/T and both H and T are negative, then S will be 
positive.  More important to me is the flaw in your physics.
     It is not true that if the temperature decreases, the heat must 
decrease.  Heat and temperature are related, but very different things.  I 
can offer two brief examples.
     When you melt ice, the ice is absorbing heat, but its temperature will 
not change until all of the ice is melted.  You can see this yourself if 
you freeze a thermometer into a beaker of ice overnight so that it is nice 
and chilly (perhaps -10 or -20 degrees C) the next day.  Then put the 
beaker on a table or a slightly warm surface that will heat the beaker up 
(a hot plate on a low setting will work).  Take the temperature of the ice 
every couple of minutes.  When the temperature reaches 0 degrees C, you 
will notice that the rise in temperature levels off as the ice turns to 
water.  When the substance becomes entirely water, the temperature will 
begin to rise again.  The point is that while the ice is changing phase 
from solid to liquid, it is absorbing heat while the temperature remains 
constant.  
     The second example I have is the adiabatic expansion of a gas.  In an 
adiabatic expansion, no heat is lost by the gas.  This is the situation 
that exists in either a very rapid expansion or in a well insulated 
expansion.  As the gas expands, its temperature must decrease (both the 
pressure and the volume are decreasing, so the temperature must also 
decrease) but the amount of heat in the gas remains constant.  This second 
example best describes the expansion of the universe.  Often when you see 
the expansion of the universe described, you will see the term "adiabatic 
expansion" used.  The reason for this is that there is nothing for the 
universe to exchange heat with and so the expansion must be adiabatic.
     Actually, apart from what I have pointed out here, your arguments are 
quite sensible.  One of the acid tests of any theory is to stack it up 
against the second law of thermodynamics, and it is with this sort of 
analysis that objections to theories are raised.  Often it results in a 
better understanding of the physics as the situation is reviewed in a new 
light.  So keep asking questions like this one!