On Wed, Mar 19, 2014 at 02:40:16PM +1300, LizR wrote: > On 19 March 2014 14:27, Hal Ruhl <[email protected]> wrote: > > > Hi Liz: > > > > Hi Hal > > > > > The physics that I learned holds that the energy in a universe is > > constant. Therefore entropy in such a universe can not exceed 100% of this > > energy being unable to do work. That seems a max limit to me. > > > > The increase in the entropy ceiling is caused by expansion of the universe. > This effectively increases the potential energy of its constituents. This > would still reach some maximum in a universe without dark energy, however, > note that the vacuum energy thought to be accelerating the expansion of the > universe is constant per unit volume, and so the amount of it increases > indefinitely in an expanding universe. Although it may not be harnessable > by life or other "entropic" systems. >
More to the point, our best cosmology models give a value of precisely zero for the total mass-energy of the universe. This is because the mass-energy we see is exactly balanced by the negative gravitational potential energy. So an expanding universe should give rise to increasing maximum entropy, but the total energy remains constant (at zero). As for what happens to the free energy (stuff available for work), its a bit more complicated, but it appears that processes reducing the free energy (or increasing the entropy, as its the same thing) are not currently keeping up with the increase in maximum entropy caused by an expanding universe. -- ---------------------------------------------------------------------------- Prof Russell Standish Phone 0425 253119 (mobile) Principal, High Performance Coders Visiting Professor of Mathematics [email protected] University of New South Wales http://www.hpcoders.com.au ---------------------------------------------------------------------------- -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
