Freethought & Rationalism Archive

liquid · 04-08-2002, 03:05 PM

As some of you might recall, as an aerospace engineer one of my particular areas of cre/evo interest is thermodynamics. I was just browsing around the sci.skeptic FAQ when I came across this. It's a very neat little calculation and I am surprised that I haven't come across it before. Of course, it's essentially trivial because the system is open, but it's a nice demonstration of the scales involved. It might be worth getting the reference data and doing a nice write-up.

Quote:

It is interesting to observe that an enormous amount of entropy production is actually associated with the formation of life on earth.
According to Plank (father of quantum mechanics) the entropy flow from the sun is proportional to the reciprocal of the sun's temperature[I assume planck made the argument but I'd just like to note that this proportionality comes from the basic mathematical form of the second law for heat engines and has been around a long long time - Liquid].
More precisely it is four thirds times the heat transfer from the sun all divided by the temperature of the sun (about 6000 kelvin). By the law of conservation of energy (and ignoring global warming) the heat flow from the sun to the earth is equal to the thermal radiative heat transfer from the earth to outer-space. The entropy flow from the earth is therefore four thirds times the heat transfer from the sun all divided by the temperature of the earth as seen from outer-space (about 300 kelvin = 27 celsius). Therefore, the entropy flow from the earth is greater than the entropy flow to the earth which means that entropy has been produced on earth (via friction, etc.).

Thread Tools	Search this Thread
Show Printable Version	Search this Thread: Advanced Search

Freethought & Rationalism Archive

The archives are read only.