[gib65]

I googled for "define: entropy" and came up with this:

"A measure of the disorder in a system."

I also entered "entropy" into www.dictionary.com and found, among other definitions:

"The tendency for all matter and energy in the universe to evolve toward a state of inert uniformity."

So if I understand this correctly, entropy is the phenomenon observed when, for instance, an elastic band goes from stretched to slack or a building going from erect to rubble when demolished by means of explosives. Is this correct?

If so, what do we call the opposite phenomenon - that is, the building up of physical systems from something simple with uniformly distributed energy to something more complex and non-uniformly structured?

[JaKiri]

Creation of order.

But creation of order creates more chaos than the order anyway.

[YT2095]

in Chemistry it`s "Enthalpy"

http://en.wikipedia.org/wiki/Enthalpy

this may help too: http://www.mathpages...84/kmath184.htm

[Artorius]

atrophy....or is that a pint of beer

[YT2095]

I thought that was Muscle wastage from lack of use, Grey matter for example :P

[swansont]

Asking what the opposite of entropy is, is like asking, "What's the opposite of temperature?"



If you want to lower the entropy you have to do work, and the entropy will have to increase somewhere else, as JaKiri stated.

[YT2095]

Swansont, is there a word/term for this though?

[gib65]

Does the universe necessarily have to end in a state of disorder? I only ask because I've come to understand entropy to be a law that all physical systems succumb to eventually. But obviously, there are both entropic and "enthalpic" (thanks YT2095) processes in the universe. Why would the entropic processes prevail in the end? What about states of equilibrium?

[chadn]

Quote

in Chemistry it`s "Enthalpy"

enthalpy and entropy are two different things

theres even a way in which to relate entropy to enthalpy

G=H-TS

H being enthalpy
T being absolute temperature
S being entropy.

and G being Gibbs Free Energy

There isnt really anything I'd call the opposite of entropy. The closest thing would probably be Gibbs free energy, which is the energy from a reaction that is not lost to disorder. If you think of enthalpy as the total energy in a reaction released and entropy as the energy lost to disorder then the difference is that energy which is still available to do work or increase order. This difference is called Gibbs Free energy.

[YT2095]

Oh for Crying out loud!

I`m perfectly familiar with delta G thanks :)

that`s why I used it, and stated "IN CHEMISTRY"!

[Les Sleeth]

gib65 said:

So if I understand this correctly, entropy is . . . what do we call the opposite phenomenon - that is, the building up of physical systems from something simple with uniformly distributed energy to something more complex and non-uniformly structured?

Hi everyone, this is my first post here. :-)

I realize you are probably looking for a purely physical answer, but in terms of behavior at least, two apparently anti-entropic processes are the ordering that results in adaptive evolutionary change (remarkable since through reproduction it can last for a long time), and the tendency to order things a healthy consciousness exhibits. Of course, everyone knows in terms overall disorder (via metabolism, aging, etc., entropy still prevails.

[[Tycho?]]

Quote

in Chemistry it`s "Enthalpy"

http://en.wikipedia.org/wiki/Enthalpy

this may help too: http://www.mathpages...84/kmath184.htm

Uh, I dont think so. In chemistry we've studied entropy and enthalpy as different subjects. On is S, and I think the other one is G although I dont remember which is which.

But yeah, opposite of entropy is order. Usually things move towards a state of disorder, so the opposite of that would be the sponanteous ordering of a system.

[JaKiri]

Les Sleeth said:

two apparently anti-entropic processes are the ordering that results in adaptive evolutionary change

They aren't antientropic. They obey the 2nd law, and aren't very efficient either.

[Les Sleeth]

JaKiri said:

They aren't antientropic. They obey the 2nd law, and aren't very efficient either.

Hmmmmm, did you read my entire post? Anticipating someone thinking I don't understand entropy, I tried to make it clear I wasn't suggesting they didn't obey the second law; everything does. I specifically pointed to behavior and not to the thermal processes involved in achieving that behavior.

Part of the problem is that the term "entropy" has been expanded from thermodynamics to a general term for the ever-growing disorder in the universe. In my own mind I think about two variations as thermodynamic entropy and structural entropy, respectively. In terms of gib65's question, he seemed to be thinking about the more general, or "structural," use of the term.

In our universe, there are no known examples of extended ordering (structural antientropy) which surpass that found in life and consciousness. As impressive as the formation of the complex dynamics of a star is from collapsed interstellar gas, for instance, it doesn't hold a candle to billions of years of layer after layer organizing done through evolution. If anything comes close to structural antientropic behavior, evolution has to be a top candidate.

But then there is consciousness. Look at us, building, learning, creating, trying to survive . . . all of it structurally antientropic behavior. Of course, assuming consciousness emerged from life processes, that sort of makes sense.

My point was that although there is no thermodynamic term for antientropy, there are instances of extraordinary structurally antientropic behaviors which we have termed "life" and "consciousness."

[JaKiri]

It was the 'apparantly antientropic' that threw me, because it's quite clearly not.

[premjan]

Does entropy depends on the cosmological model? I think the big bang universe is one where entropy continuously increases, but there are other (less favored) cosmological models where low-grade energy may recycle back as mass.

[gib65]

Yes, yes, all very good, but what do the laws of entropy say about the fate of the universe (now that I know to distinguish between thermodynamic and structural entropy - thanks Les - I refer only to the structural type). Is the universe doomed to settle into a field of floating debri without much life to it at all, or is there hope that the universe could evolve into something greater from which it will never degrade, or at the very least continue forever in a state of equilibrium (with moderate fluctuations now and again). For instance, the idea that the universe will eventually collapse upon itself in a "Big Crunch", and then a "Big Band", and yet another "Big Crunch" after that, and so on, seems to me like a system that will never succumb to entropy. Or what about the Moon orbiting the Earth, or an electron orbiting a proton? Don't these represent systems in states of equilibrium such that the one body will continue to orbit the other indefinitely?

I'm not a physicist, so I'm not trying to strike a blow at the theory of entropy. Just asking 'cause I wanna know.

[TimeTraveler]

Quote

Yes, yes, all very good, but what do the laws of entropy say about the fate of the universe (now that I know to distinguish between thermodynamic and structural entropy - thanks Les - I refer only to the structural type). Is the universe doomed to settle into a field of floating debri without much life to it at all, or is there hope that the universe could evolve into something greater from which it will never degrade, or at the very least continue forever in a state of equilibrium (with moderate fluctuations now and again). For instance, the idea that the universe will eventually collapse upon itself in a "Big Crunch", and then a "Big Band", and yet another "Big Crunch" after that, and so on, seems to me like a system that will never succumb to entropy. Or what about the Moon orbiting the Earth, or an electron orbiting a proton? Don't these represent systems in states of equilibrium such that the one body will continue to orbit the other indefinitely?

I'm not a physicist, so I'm not trying to strike a blow at the theory of entropy. Just asking 'cause I wanna know.

I think entropy happens so slow on a universal level and the universe is so big it will be tens or hundreds of billions of years before it would pose any major effect. If there was to be a big crunch I think that would happen long before entropy effects were felt. But yes the universe is slowly decaying because of entropy (very slowly). The moon will not orbit the Earth indefinitely either will the Earth orbit the sun. Eventually they will succumb to gravity, I don't think entropy will play a role in that. I think the moon was estimated at about 50,000 years not sure about the Earth, 5 billion years maybe.

[JaKiri]

Entropy will play a role in that, in the sense that it is due to there being no perpetual motion device, if you see what I mean.

[Les Sleeth]

gib65 said:

. . . but what do the laws of entropy say about the fate of the universe (now that I know to distinguish between thermodynamic and structural entropy - thanks Les - I refer only to the structural type).

I think other posters are suggesting that entropy alone may not be the only factor determine the fate of the universe, which is true.

But just answering your question posed above, the law of entropy, considered as the only determining factor, says the universe is going to disintegrate.