----- Original Message ----- From: "Andrew Paul" <[EMAIL PROTECTED]> To: "Killer Bs Discussion" <[EMAIL PROTECTED]> Sent: Tuesday, September 21, 2004 5:51 AM Subject: RE: indeterminacy, chaos, and complexity
> From: Dan Minette [mailto:[EMAIL PROTECTED] > >>> There is no reason why the entropy of an open system cannot > >>>be reduced.as long as the entropy of other systems that are connected to > >>>this system rise at least as much as that system falls. So, localized > >>>drops in entropy, which appear paradoxical to the casual observer, can be > >>>seen to be very compatible with the laws of physics. > >> > >> I have long found this topic interesting. Does this have any sort of "action at > >> a distance" implications. How is the rise of apparent order, in the form of life on > >> earth say, balanced by some entropy increase elsewhere. And what form does this > >> take. When I mow my lawn, does some distant sun go supernova? A silly example > >> perhaps, but how is the presence of life (which does seem rather anti-entropic) > >> balanced somewhere else, in another system. How does this other system know > >> to become less ordered? > > >Becasue they are connected. Penrose has an absolutely brillient and > >intuative discussion of this in "The Emperor's New Mind" > > I confess, I purchased that an an airport, and never finished it. > > > >The sun radiates photons from its surface at ~4000K via blackbody > >radiation. They peak around yellow, in the visiable spectrum. The earth > >receives these photons as energy in a relatively low entropy form. Its in > >(roughly) thermal equilibrium, so it must radiate the same amount of energy > >out. But, since it is at, roughly, 300K, it radiates ~10x the number of > >photons each of which has ~10% of the energy of the sun's photons. > > >This is a significant increase in entropy. Plants produce internal lower > >entropy states by absorbing the higher energy photons, and using them in > >photosynthesis. If you look at the entrophy of the photons that hit the > >earth, and compare it to the entropy of those radiated by the earth, you > >will see a much larger increase in entropy compared to the decrease of > >entropy in the plants. > > > I can see where you are coming from here, but humour me... > > The earth re-radiating heat is going to happen, regardless of the presence of > life or not. The entropy increase is dependent on the temperature differential ? In a sense. 20 low energy photons are in a higher energy state than 1 higher energy photon. One way to look at it is to look at the probability of just happening on the state. There are many ways for 1 higher energy photon to intereact, with 20 low energy photons being the result. The reverse process is very unlikely. Its like the difference between having 100 marbles lined up in 10 nice tight rows of 10, and having them skattered all over a big box. If the box with the nicely arranged marbles is shaken, we know what will happen. There will be marbles all over the box. If the box with the scattered marbles is shaken, then it is theoretically possible to get 10 rows of 10, tightly packed, as the result. But, this is one particular state, with only one case. There are billions of ways to have marbles scattered all over the room, and very few ways to have them neatly in rows. The entropy increases as the marbles scatter. The same thing happens with the photons. Now, Penrose gave the metaphore of a waterfall as an example. Naturally, the water just goes down the falls, increasing its entropy. If one puts a waterwheel in the falls, one can do useful work. One can lift objects up a nearby cliff, for example, decreasing their entropy. Photosynthesis is like that waterwheel. Dan M. _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
