5.6: "The second law of thermodynamics says.... (Creation versus Evolution)
Description
This article is from the Scientific Skepticism FAQ, by Paul Johnson Paul@treetop.demon.co.uk with numerous contributions by others.
5.6: "The second law of thermodynamics says.... (Creation versus Evolution)
...that entropy is always increasing. Entropy is a measure of the
randomness in a system. So the universe is getting more and more
disordered. But if this is so, how can life happen, since
evolutionists claim essentially that life is a system that becomes
more ordered with time?"
[ The following answer was kindly contributed by
Dr. Roydon A. Fraser, Associate Professor,
University of Waterloo, Waterloo, Ontario, CANADA.
email <rafraser@mechoffice.watstar.uwaterloo.ca>. ]
This line of reasoning would be valid if it were not for the simple
fact that the above is a misstatement of the second law of
thermodynamics. A correct statement reads,
"The second law of thermodynamics states that the net entropy
within an ISOLATED system is always increasing or remains
constant."
An isolated system is one that does not undergo a change of state due to
external work or heat transfer. The entropy in an isolated system in
equilibrium is constant at its maximum value.
The major key here to demonstrating that life on earth does not
violate the second law is to realize that the earth is a NON-isolated
system. The earth is continuously absorbing radiative heat transfer
energy from the sun and continuously transferring thermal energy to
outer-space through thermal emissions. Because the earth participates
in these heat transfer processes it is non-isolated.
For instance, when you freeze water the molecules of H2O line up in
beautifully organised crystals. This organisation does not violate
the second law of thermodynamics because the work done by the freezer
in extracting the heat from the water has caused the total entropy of
the *universe* to rise, even though the entropy of the *water* has
decreased.
Similarly the existence of life on earth has not decreased the entropy
of the universe, so the second law has not been violated.
From a classical thermodynamics perspective the universe as a whole is
isolated, and hence, the net entropy (disorder) of the universe
continues to increase (the situation where the universe's entropy
remains constant does not exist because we live in a universe with
friction).
The second law states that the entropy of the sun plus the earth's
entropy plus the entropy of outer-space (i.e, the net entropy) cannot
decrease. It is completely acceptable for the entropy of the earth to
decrease provided the net entropy of the sun and outer-space
increases. As an analogy consider the freezing of water into ice.
The entropy of ice is less than that of water because ice molecules
are more organized (they are in a crystal lattice) than water
molecules (which move about randomly). That is, the water's entropy
has decreased, but only at the expense of increasing the
entropy in the room and at the expense of a net increase in the
universe's entropy (i.e., by the second law the entropy increase in
the room must be equal to or be greater than the entropy decrease
experienced by the water).
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.
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.).
In conclusion the existence of life on earth does not violate the
second law of thermodynamics.
Continue to:
My Books
