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Question entropy rises over time right?

  1. Mar 30, 2006 #1
    i have a question
    entropy rises over time right?
    how is a ball of hot plasma more organized than the modern universe with its galaxies, planets, and people?
  2. jcsd
  3. Mar 30, 2006 #2


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    Staff: Mentor

    The entropy of the universe rises over time. Local entropy can fall as long as it increases the entropy around it.
  4. Mar 30, 2006 #3
    In a finite expanding universe, entropy increases.

    Forget the word "organized" here. It will only mislead.

    First, the SI unit of Entropy is J/K. That means Joules per Kelvin (not "just kidding" :tongue2:)

    That means in simple terms the ratio of mass-energy to temperature.

    Consider the universe's changing entropy:

    The far-away Cosmic Background Radiation used to be 3000 degrees Kelvin. Now it is a little under 3 degrees Kelvin. The mass hasn't decreased by a factor by 1000, whereas the temperature has. That's why the universe is increasing in entropy.

    J/K is increasing.
    Last edited: Mar 30, 2006
  5. Apr 3, 2006 #4
    what if the universe was static(somehow) or even collapsing?
    then would the entropy stay the same?
    or even lower?
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