Friday, March 25, 2011

Entropy, how I loathe thee

So, isentropic processes are pretty cool.  It's where the entropy in state 1 is equal to the entropy in state 2, or no change in it, basically.  Unfortunately, no such process exists.  It's only an idealization by engineers to simplify problems where entropy change is negligable.  And trust me, dealing with entropy is a serious pain.  I can upload pictures of homework pages long for a single problem solving for it :(

Entropy, and thus, disorder, always increases in the universe whenever energy is being used.  What exactly does that mean?  Here's a simple example.  Say you have a jar of various sized rocks with different densities (mass/volume) in no particular order throughout.  If you shake the jar either with your hands or a machine, the rocks will arrange themselves so the highest density larger rocks are on the bottom and the smaller rocks are at the top.  That seems to be more ordered, doesn't it?  So how can entropy increase?

The answer is that even if you have a process which provides ideal work (also an idealization and impossible) or 100% efficiency for the energy into the system, it still will take more energy to get the rocks back into their original positions.  So, entropy has increased even though the rocks appear to be more ordered!  This, and of course the fact the process you use (your body or a machine) to shake the rocks also increases the entropy.

Of course, eventually the universe will be filled with so much entropy the energy required to get useful work done will be impossible.  Interestingly, proton half-life has been measured to be about 10^40 years.  I wonder if the protons will decay before the entropy wins!?  Everything in the universe has a death date, it seems.  Supermassive black holes will be the last thing to go at 10^80 years.  Luckily for those black holes that's a ridiculously long time.  Maybe vamps will still be around, they are immune to suffocation and freezing, right?

Comments appreciated and thanks for reading!

Have some future posts lined up, got a request to do something on time travel and I will be doing a piece about this awesome idea I had for a moon base on Europa, and future civilizations view of the universe!

18 comments:

  1. good thing we'll be long dead before black holes, and the sun crystalizing, yes?

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  2. Interesting. I suppose this theory holds up on a molar level too. The more force or tension between two opposing forces (whether it be waring nations or feuding couples), the harder it is to return them to a state of peace and calmness. Hmm..

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  3. um i think you're over my head with this one :)

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  4. hmm...
    interesting indeed. it makes sense, although i feel as if there are factors that aren't being considered here simply because there would be too many to consider.
    if you take requests can i request you blog about gyroscopic force and it's possible application in transportation especially space transportation.

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  5. @Asty well actually the sun will go into a silent highly condensed mass of heavy elements when its fusion stops, basically sitting silently (and darkly) in space for eternity. pretty metal death, i'd say!

    and if we do end up conquering our biology and having an indefinite lifespan (and I believe we will, I might post about it), it is a high statistically improbability that we won't perish via some kind of various accident (space ship hits something, supernova kills us, etc) in 10^40 years lol, even in the several billion till the sun does that )

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  6. I hope we'll all be dead before all of this! Whewwwww.

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  7. Entropy...that's my excuse for my room right now.

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  8. @stevesonaplane hahahah )

    there's a set of mock nobel prizes given out each year for ridiculous discoveries, and i remember maybe 2 years ago one of them was that a box of cords will naturally tangle themselves over time. that explains christmas lights! and it sounds like your room, right

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  9. I've read some stuff on entropy before, but your post refreshed it for me. Thank you for sharing this.

    Keep 'em coming! :)

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  10. So all things really do eventually come to an end.

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  11. I remember entropy from physics class. Oh yeah, i also remember failing. Followed! alphabetalife.blogspot.com

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  12. Interesting post as always Xuian, cheers

    I was watching a program on the possibility of terraforming Mars, do you have an thoughts on that?

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  13. Great post bud, I always enjoy reading your blog. I look forward to the time travel as well. ;) Keep up the great work!

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  14. @Danny Murphy, terraforming mars would be so insanely expensive it's just like.. Almost impossible to think of. Within the next 30-50 years anyway.

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  15. absolutely very expensive. I can do a post on it because it's interesting to me. What's funny to think about is if we weren't in a capitalistic society 'money' wouldn't be that much of a problem )

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