Re: Policy asked to investigate entropy-claim in website of Turku University in Finland

On Mar 29, 11:14 pm, "Perplexed in Peoria" <jimmene...@xxxxxxxxxxxxx>
wrote:
"Mark Iredell" <im.b...@xxxxxxx> wrote in messagenews:1175210569.048973.3600@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Perplexed in Peoria wrote:
"Mark Iredell" <im.b...@xxxxxxx> wrote in messagenews:1175132372.307658.168890@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Perplexed in Peoria wrote:

...energy from the sun DOES increase entropy on Earth....

The sun radiates Earth with high-energy photons, while Earth in turn
radiates to space with low-energy photons. Earth's net energy change
through this process is zero (neglecting the small amount of heating
coming from the Earth's core), but the net entropy change is NEGATIVE.
That is, the net radiative effect of the sun truly DECREASES the
Earth's entropy. As we know, the biosphere makes good use of this
source of negative entropy.

You are using rather creative 'accounting rules' to reach this conclusion.
For example, the idea that those low-energy photons which the Earth radiates
to space at night should be counted as something that the sun does to Earth.

It's simplest to look at the problem from the point of view of space.
Consider just the closed sun-Earth-space system. The presence of the
warm Earth robs cold space of high-energy photons in exchange for low-
energy photons.

Your rationale seems to be that (in order to be fair) we need to analyze
a steady state system. Ok, if that is the approach you wish to take, I
would ask just how long you think the Earth has been in a steady state with
its entropy decreasing.

Entropy is only conserved under reversible processes. Low entropy is
continually eroded on Earth by irreversible processes, such as life.

Furthermore, the sun shines mainly in the tropics where it's already
hot. This further decreases entropy. I can't say if the biosphere uses
this extra source of negative entropy, but the atmosphere sure does.

Ok, that almost makes some sense. Your accounting rules now have the sun
pouring photons on the hot tropics, and the cold polar regions radiating
the same total amount of heat (at lower temperature) to space. And the
negentropy drives convection - palpable work is being done. Ok, but
then you are apparently not accounting for the entropy generated by
the frictional resistance to the convection.

So your position seems to be that by choosing the accounting rules cleverly,
we can say anything we want about thermodynamics. Gee, don't tell the
creationists about this! They might get ideas. And use this creative
accounting dishonestly!

I don't think considering just the closed sun-Earth-space system is
arbitrary. I think it's the simplest way to look at the problem.

[2nd repost- damn SBC/ATT to hell!]
It is not an absurd way to look at the problem - depending on
what problem you are looking at. Suppose you see the problem
this way: We notice a number of dissipative processes on
Earth, including the hydrological cycle, atmospheric
circulation, and green plant growth and decay. These
processes produce entropy, yet the entropy of the Earth does
not seem to be increasing - we are not approaching equilibrium
- we remain in a rough steady state far from equilibrium. What
is the explanation? What is the source of negative entropy?

If this is the question you are asking, then the correct
answer is indeed that we are emitting high entropy photons to
space while replacing the energy lost by absorbing low entropy
photons from the sun. (Lower entropy because there are fewer
of them - not lower entropy per photon, but lower entropy per
joule).

An entirely correct analysis. But it remains the case that
each photon we receive from the sun *increases* the entropy of
the Earth.

Well, I'm confused, which is what normally happens every time
this issue is raised. I'll make a guess about what you mean
and you can tell me how close I am to correct:

- Energy from the sun increases the entropy on earth.
- The less usable energy from earth increases entropy of space
even more.

Therefore subract entropy_received_from_sun from
entropy_going_to_space_from_earth and entropy on earth is
decreased. That is the source of negative entropy on earth.


Assuming the above is what you meant, I have a different take
on this entire issue, which is normally met with a deafening
silence each time I raise it, so I will present it again here
in the hope that it will prevent you from replying to (and
thus criticizing) my comments above.

In my view the fundamental source of negative entropy in our
universe is gravity. Basically I think that gravity has a
different opinion about what entropy is than do the other
forces. So gravity is forcing matter in planets and stars etc.
into a state of lower entropy from the point of view of the
weak, strong and electromagnetic forces.

And that was the entirely correct point of the entirely stupid
creationist who called in the cops. And then the university
spokesman showed himself to be even stupider by saying that
analyzing the thermodynamics of this situation is a
Nobel-prize level research topic. If it is so damned
difficult, why are they claiming they have the answers on a
web site?

For the same reason AIG has an explanation for coal mines on
its site.

I feel better now that I have that flame out of my system. ;-)

Hopefully this will add order to your thinking.


Cordially;

Friar Broccoli
Robert Keith Elias, Quebec, Canada Email: EliasRK (of) gmail * com
Best programmer's & all purpose text editor: http://www.semware.com

--------- I consider ALL arguments in support of my views ---------

.

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