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Entropy vs Life

  1. Jun 17, 2011 #1
    How do life and all processes linked to life go along with the second law of thermodynamics? If living creatures decrease their entropy because they are open systems and in a state of non-equilibrium with the environment, in general does the total entropy increase? (for example, if we have two exactly equal planets, does life evolution bring about a greater increase in entropy?) Is it correct then to conclude that, in some ways, nature uses life to achieve a higher state of entropy?
     
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  3. Jun 17, 2011 #2

    ZapperZ

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  4. Jun 17, 2011 #3
    I would not conclude that. Entropy increases with our without life. By consuming the plants formed on planets life is not making a very significant contribution. Most of the entropy in our universe is in dead stars.
     
  5. Jun 17, 2011 #4
    @ZapperZ: thank you for the very informative articles (I really enjoyed reading them). Could you perhaps clarify some points?

    1. If I am getting it right, entropy decreases because of day/night temperature differences and this decrease is much greater than the decrease in entropy due to life evolution, by several orders of magnitude. However, the decrease due to the sun is not related to life at all: it would be present even in Dead-Earth. But this decrease in entropy is what can possibly drive evolution and indeed for this reason the overall rate of entropy increase is positive. So my claim was wrong: if life didn't exist, entropy would be higher (I believed that, organizing themselves, living beings brought about greater increase of entropy in the environment. Maybe life is a statistical byproduct, whenever the conditions are permissive?). Did I understand Bunn's argument correctly?

    2. Could you explain these passages:

    'In this estimate we did not include any entropy increase due to thermalization of the radiant energy emitted by the Earth. If we assume that this radiation eventually thermalizes with the cosmic background (CMB) radiation in deep space, then an additional, much larger entropy increase results' What is thermalization?

    'With these assumptions, we can use the standard thermodynamic result mu/T=- partial S/partial N' I don't know how he came up with this.
     
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