🚀 go-pugleaf

Fred McGalliard  <frederick.b.mcgalliard@boeing.com> wrote:
>Christopher C. Wood wrote:
>
>> "Living systems" would be in equilibrium if what goes out is the same
>> as what goes in.  Last I looked, food and oxygen were different from
>> CO2 and human waste.
>
>Be careful. If you draw your circle around a community of organisims,
>rather than just an individual, your subject may certainly be in
>equilibrium. The current dynamic equilibrium is supported by the steady
>input of solar power, and is remarkably stable over all.

True, but what goes out is still different from what came in
when viewed in a global context.  The energy per photon coming
in from the Sun is much larger than the energy per photon radiated from
the Earth.  If you look at the energy flow through a system
you can see the entropy change.

"Quis tamen tale studium, quo ad primam omnium rerum causam evehimur,
tamquam inutile aut contemnendum detractare ac deprimere ausit?"-Bridel

Ethan T. Vishniac ---> http://grendel.as.utexas.edu/Welcome.html
Dept. of Astronomy      also Associate Professor of Astrophysiology
The University of Texas      G.G. Simpson Hereditable Chair of Evilution
Austin, Texas, 78712         University of Ediacara                   
ethan@astro.as.utexas.edu    `Knowledge, Wisdom, Beer'