Roger Penrose has penned a massive tome that takes on a pretty big job--that of addressing the physical laws that hold our universe together.  The equivalent of a B.S. in physics would seem to be the bare minimum required for the reader to make much sense of this book, with a Ph.D. in that discipline leaving the reader still less than completely prepared!  Of course the author himself freely admits that much remains that baffles him, including that apparently incomplete work known as quantum theory.<br><br>Nevertheless, many aspects of physics are explained in a way that at least seems not too difficult to understand.  On p.705 the author describes the Sun as Earth's entropy sink--with high energy photons absorbed by day--with many more low energy photons given off as that part of the Earth turns away from the Sun by night--and with the proliferating nocturnal low energy radiation quanta flows a large measure of entropy.  Meanwhile the entropy of black holes increase with the surface area of such objects--thus providing the entropy sinks of last resort for our universe.  So now I can at least begin to see how you can have a relatively well-ordered and life-bearing planet like Earth while still maintaining the monotonic increase in entropy within the closed system that is our universe.  This argument has stimulated me to imagine how a plant might accomplish its mission of alternating the population and depopulation of energy levels in such a way that the absorption of high energy photons and subsequent radiation of low energy photons allow that plant to achieve its own local reduction in entropy.