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Show ALL Forums  > Science/philosophy  > Entropy, Does it Change Over Time?      Home login  
Joined: 9/3/2011
Msg: 5
Entropy, Does it Change Over Time?Page 1 of 1    
Let me just emphasize one point here, entropy is a tendency within a closed system. In this case, the only known truly closed system is the universe itself (a closed system being one with no interaction with anything around it and the universe qualifies for any decent definition of the term "universe"). A lot of misunderstandings with entropy miss that point.

Now, can entropy change or reverse over time? Maybe, though the mechanism of how a law of the universe like that might change isn't known at this time. Though if it was possible then the universe would become a rather strange place.
Joined: 1/16/2008
Msg: 6
Entropy, Does it Change Over Time?
Posted: 9/9/2011 6:57:49 PM
It should also be noted that, while the overall trend in the universe is towards increased entropy, there can be pockets of decreased entropy and/or increased order. Emergent order out of chaos. This is not a violation of the laws of thermodynamics because the overall trend is toward an increase in entropy.
Joined: 5/26/2011
Msg: 7
Entropy, Does it Change Over Time?
Posted: 9/12/2011 8:17:18 PM
The pockets of order themselves follow in line with chaos on a larger scale - in any truly chaotic system, even order must be present in some form for there to be the disorder and randomness of chaos in the first place.

Systems break down over time, but the systems by which the breakdown occurs are also processes with their own system and rules. Really, what were talking about isn't a matter of the universe doing anything different, rather quite simply a matter of SCALE.

Joined: 8/16/2011
Msg: 8
Entropy, Does it Change Over Time?
Posted: 9/13/2011 5:43:08 PM
I do not understand the concept of "packets of decreased entropy".

As I understand it, entropy is borne out of the fact that energy differential is needed to create useful work. Energy does not decrease, but the differentials tend to even out each time some energy is used up to heat something. Because you can't cool something, only heat it.

Take water evaporation, for instance. It seems you cool something by evaporating water that is on it. But what you do is heat up the water to make vapour out ouf it, and the body on which the water is sitting, also gives some of its heat to the water.

The apparent effect is that the body cooled down, but nobody thinks of the water that heated up.

When you burn a piece of wood, heat energy is created, which is impossible to put back into matter. When you combine carbon dioxide and water to make oxygen and carbon, and molecular hydrogen, you apply energy, true, so it's almost like you are putting heat back into the product of burning wood to get the wood back. But you are not adding heat. You are adding energy in another form.

Entropy is not called the "third law of thermodynamics" for nothing. Entropy's basic functionality is gained by the universe's inability to put heat back into objects and get something cool again. Like burning some wood, and then reversing the chemical reactions.

All effective cooling takes energy.


That said, what do you mean "decreased entropy"? In this context. Order, in my very own opinion, is an interpretation of entropy, an apparent effect of it. But it is not part of the law, maintaining order is not necessarily an entropical event, in which a system entropy is reveresed. Inactivity can maintain order, and random events can create order. Order, in effect, is a human concept borne out of human perception and opinion. Order is not a value or attainable objective in the universe outside of what a human minds sees it as.


Is decreased entropy a way of creating useful energy out of useless energy? Creating energy differentials that had not existed before?

That is impossilbe to do.

There may, just may be a way that from the human standpoint "usefulness" is harnessed, but in a physics way that is not possible. Remember, in a human valuation "useful" is something that makes you happy, directly or indirectly. In a physics sense, "useful" means that a potential of energies exist which can create a work situation, in which force is used to accelerate bodies, or move them against other resistance different from inertia. You can't create this difference of energy potentials. If you could, then entropy would be shown to not exist.
It is extremely dangerous to not recognise equivocations. In this sense, a usefulness by human valuation is equated to a usefulness in the physics sense. Aristotle showed how and why this is wrong to do, so let's not do it.

My question, at its very basic, what is "decreased entropy"? In the physics sense.
Joined: 5/26/2011
Msg: 9
Entropy, Does it Change Over Time?
Posted: 9/14/2011 6:07:33 PM
Entropy in the broader sense is a measure of any systems disorder. Eventually everything degrades into inert uniformity, and yet here we are....a globular sphere of chaos, untold amounts of energy shifting and changing forms in every moment. Every plant, animal and process balances out in a way to keep the system running without any outside influence except for that of the sun. Very little waste or inefficiencies in the larger sense, as there is always something else to change energies form, and recycle it back into the system to be used again.

That is, until we evolved and became the all powerful rulers of the planet. Making chemicals and such that throw the balance off and stop the systems from running properly to continue on support life forms. Humans are a curious thing, we have both the power to continue on for untold millennial, or to simply blow our traveling green globe into cold space rocks.
Joined: 9/7/2011
Msg: 10
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Entropy, Does it Change Over Time?
Posted: 9/15/2011 3:54:13 PM
It seems to me the definition of entropy is dependant on the definition of order and disorder, and personally I don't believe in disorder no matter how disordered it appears because chaos itself is said to be order. Another factor is the apparent/theoretical continuing creation of energy within the universe, apparently/theoretically increasing at a faster rate as the universe ages. Is a tree's log rotting away entropy or simply a change in order which promotes mushrooms? Is a machine's rust entropy or simply a reverting to original order, an undoing of mankind's interventions? Physics seems bound with philosophy, and Einstein said imagination is more important than knowledge.
Joined: 6/29/2009
Msg: 11
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Entropy, Does it Change Over Time?
Posted: 9/16/2011 1:40:37 AM
Thanks, canoequiet, that's exactly what I have long thought about the whole "entropy" concept. It always seemed to be a very anthropocentric sort of idea, wherein "entropy" was defined as "stuff tends to turn into stuff we can't use all on it's own. "

But then, I'm a Historian-oriented person, not a physicist-oriented person. I always had an emotional reaction to the idea of entropy, because the idea of ever increasing entropy sounds so bleak, and makes all struggles against it ultimately pointless.

As to what a 100% entropy-achieved universe might look like, I wonder if perhaps the common street version of molecules and atoms adrift in a lifeless, cold darkness is really accurate. First, I'm in no hurry to find out, but since we've seen by way of the fact that WE exist as we do, that the natural result of OUR situation has been in INCREASE in order (evolution of beings hasn't resulted in LESS complicated organisms after all), maybe the "entropic" universe would ALSO have order to it.

No doubt this means I have no idea what "entropy" really means. I always thought it meant "systems tend to balance themselves, thermodynamically, owing to the nature of heat energy being gregarious." Thus, all existence will eventually become 'tepid.' I certainly DO recognize from repeated experimentation, that this is true of all tea.
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