Evolution's constituency

[Erasmus00]

Taking these facts into account, could we also lump neutron stars into the class of object that have a decreasing value of Entropy? Their gravity is huge by comparison and should be accumulating information at rates substantially higher than even very large planets.

 

No stellar object, left to its own devices, decreases in entropy. Very massive white dwarfs turn into neutron stars in order to increase their entropy, and neutron stars continue to radiate in order to increase theirs. The only way to decrease entropy is to constantly pour usable energy into a system.

-Will

[Buffy]

No stellar object, left to its own devices, decreases in entropy.

Just remember that its the "left to its own devices" that's critical, the greater the mass, the more likely its going to be to suck up lots of stuff that wanders close enough, and as you get closer to the galactic core, there's more stuff for stars to munch on...

 

Oh-dear-now-I'm-hungry,

Buffy

[infamous]

Just remember that its the "left to its own devices" that's critical, the greater the mass, the more likely its going to be to suck up lots of stuff that wanders close enough, and as you get closer to the galactic core, there's more stuff for stars to munch on...

 

Oh-dear-now-I'm-hungry,

Buffy

And not only this example has relevance to the question about the the relationship between gravity and entropy. I'm not sure about where theory has evolved to in the last few years but, the last I heard, the details as to weather the universe is closed or open was still undecided. If the universe is closed, then all the matter, energy, and information could one day recollapse. If this is the case, how then would we view this relationship between gravity and entropy.

[Fishteacher73]

LAst I heard was that the research really split the idea...some info pointed to a colosed system, some did not... :eek_big:

[infamous]

LAst I heard was that the research really split the idea...some info pointed to a colosed system, some did not... :eek_big:

So in essence, this brings us full circle. The questions brought out at the beginning of this thread as to the relationship of Gravity and Entropy along with Complexity and Equilibrium havn't been answered. My goal was to determine how these factors interrelate with each other to apply direction to the process of evolution. I've been doing some reading about Entropy and the one thing that seems to be universally accepted is that Entropy can be associated with the direction of time. In this respect Entropy and Evolution have something in common.

[Buffy]

I'm gonna have to go back and reread this whole thread again, cuz I'm not sure what you're asking...

 

Latest data says the universe is "flat" which is the magical point between closed and open. Its important to recognize though that the amount of matter and energy in the universe is finite no matter whether its open, flat, or closed, and thus is a "closed system" (completely different kind of "closed") as far as thermodynamics and information theory are concerned. Thus over time, defining the "closed system" to be the entire universe, yes, entropy is monotonically increasing.

 

It all depends on your point of view! I'll go back and think some more...

 

Cheers,

Buffy

[Fishteacher73]

Cosmology and physics are not my strong suit, but I was thinking...

Uniform disorder would no longer be disorder... Areas of order are needed to provide disorder, right?

[CraigD]

Using this example as a true statement, wouldn't every stable celestial body in the universe be decreasing in entropy because of gravities influence? Would that hold for all bodies collecting more information in the form of energy than those bodies radiating it back into space, ex. stars?

I’m a bit confused by your wording. In the conventional mathematical sense of the word, collecting information increases entropy. But never mind, this is not an important quibble.

 

One of the abiding weirdnesses to come out of computer modeling of the solar system is that most models predict the giant planets fairly rapidly loosing kinetic energy and spiraling into closer orbits. Yet the solar system is old, and as best we can tell, the giant planets’ orbits are stable. According to some models, this is because a poorly understood mechanism where the giant planets increase their kinetic energy via a kind of ping-pong-like use of small kuiper object – comets, etc. In these models, these little objects have their orbits all kinds of disordered – ejected from the system, crashed into the sun, crashed into the giant planets, or at least perturbed into a random, very eccentric orbit – in a way that preserves the giant planets’ very regular orbits.

 

If you look at this from another perspective, it looks very like a refrigerator – the “cool” “temperature” of the giant planets’ orbits maintained by “heating” the minor bodies’ orbits. Rather than the electromagnetic interaction transferring the energy, as in the usual, thermal refrigerator, the solar system’s “molecules” – its large and small orbiting bodies – interact gravitionally.

 

The whole solar system’s entropy, or course, increases, but a particular portion of it – that due to the orbits of the giant planets – increases at a slower than expected rate.

 

All this is just speculation about models, the crazy fringes of establishment science, but I’ve always found in compellingly romantic.

[CraigD]

Cosmology and physics are not my strong suit, but I was thinking...

Uniform disorder would no longer be disorder... Areas of order are needed to provide disorder, right?

This is only true when “disorder” is used in a philosophical sense. This sense is closer to the common usage than the sense to which thermodynamics refers.

 

In thermodynamic terms, systems consisting of such stuff as ultra-cool diamonds are very ordered, while the PC that I’m using to type this post is very disordered. Intuitively, I like to think I’m creating more order via my typing than I would be refrigerating a bunch or carbon, but in the strictest physical sense, the opposite is true.

 

In informational terms, a highly random value of a binary of a certain number of bits is maximally disordered, while a value of 0 or all 1s is maximally ordered. The number representing the state of a PC is somewhere in between. Intuitively, both the random number and 0/all 1’s are disorderly in that they are boring, while the in-between case is orderly because it’s not.

[infamous]

 

In thermodynamic terms, systems consisting of such stuff as ultra-cool diamonds are very ordered, .

The issue that I'm having difficulty understanding is; why is a compact object like a neutron star viewed as having increased Entropy? Gravity has assembled these objects together, combining electron and protons to form an homogenous sphere of very organized and a more simplfied structure. Please understand, I not arguing that this is a case for decreased Entropy, I just don,t understand how this can be defined as an increased value. Doesn't the recombination of electrons and protons constitute a decrease in Entropy?

[pgrmdave]

For a good explanation of entropy, look here:

 

http://hypography.com/forums/showthread.php?p=29292#post29292

[infamous]

I’m a bit confused by your wording. In the conventional mathematical sense of the word, collecting information increases entropy. But never mind, this is not an important quibble.

The reason for the confusion may be because I have been misinterpreting the definition for Entropy. It is, to say the least, a very confusing issue this thing called Entropy. I've seen definitions that state: Entropy is the arrow of time that seeks disorder. Then I have also seen definitions that state: Black holes have the greatest increase of Entropy of any physical object. Then my mind trys to rationalize these two seemingly opposite positions and I keep comming up with the question: If gravity collects all this matter and organizes it into a single object, my logic says that gravity is assisting in the ordering of the system. I seem to be missing something here, I just can't seem to rationalize what seems to my mind as two opposing definitions for the same physical construct.

 

I really wish we could reconcile this issue, because before we can move on with our discussion of Evolution and how these five influences affect the outcome we will need to define each precisely.

[Erasmus00]

I really wish we could reconcile this issue, because before we can move on with our discussion of Evolution and how these five influences affect the outcome we will need to define each precisely.

 

Probably the most fundamental deffinition of entropy, the one that really gets to the heart of things, is what is sometimes called counting (or sometimes microscopic) entropy. I will attempt to develop the idea using a deck of cards as an example. Lets say we have a deck of cards, and we ask the question of how likely it is that the deck of cards is in one specific configuration, say arranged A-K in diamonds, clubs, hearts and spades in that order. If we assume that any arrangement is equally likely, by simple probability theory this probablity is equal to 1/(total number of different card arrangements). Now, 52 cards in a deck, so the total number of different card arrangements is 52!. This is about 1.2 *10-68. Pretty unlikely we'd find a randomly shuffled deck in this arrangement.

 

Now lets look at the probablity that the cards are in a less specific arrangement. For instance, the probability that the cards are arranged half red, half black. This probablitiy is equal to (number of ways to arrange the cards half red, half black)/(total number of different card arrangements). So, how many ways can we arrange the cards half red and half black? There are 26! ways to arrange the black half, and 26! ways to arrange the red half, so there are (26!)^2 ways to arrange the deck half and half. Actually, twice as many, because we could arrange the deck red then black, or black then red. So our probability is now 2*(26!)^2/52!=4*10-15. So this arrangement is much, much more likely then one specific arrangement.

 

What does this have to do with entropy, you ask? In physics,we deal with many particle systems, and we know our system has some energy E. We ask "how likely is the system in one particular arrangement?" We make the assumption that any arrangement with the energy E is equally likely, and we calculate the probablities. Lets go back to the deck of cards, and take the log of the probability. This log gives us log probability of some state = log (number of ways to arrange our cards in some state) - log 52!. We immediately notice that the log 52! is simply a constant, and doesn't change at all with the state. The fundamental term is the [log (number of ways to arrange our cards in some state)]. In physics, this quantity is called the entropy, though for historical reasons, we put a constant out front. Entropy = Kb*[log(number of ways to arrange our cards in some state)]. Here Kb is the boltzman constant.

 

Is this making any sense?

-Will

[infamous]

 

Is this making any sense?

-Will

Of course, yes this is the understanding that as one shuffels the deck, disorder takes place. This I understand, but clear one thing up for me if you know the answer. Looking strictly at the atomic level, in the presence of a massive gravitational field as in a neutron star, electrons and protrons are transformed into neutron soup. Doesn't this singleness of identity create a greater degree of order? Whereas before the transformation we have a number of different particles and after the transformation we achieve a unity of sorts?

[Erasmus00]

Of course, yes this is the understanding that as one shuffels the deck, disorder takes place. This I understand, but clear one thing up for me if you know the answer. Looking strictly at the atomic level, in the presence of a massive gravitational field as in a neutron star, electrons and protrons are transformed into neutron soup. Doesn't this singleness of identity create a greater degree of order? Whereas before the transformation we have a number of different particles and after the transformation we achieve a unity of sorts?

 

First, realize in the many cases it is not entropically favorable for neutron stars to form. Thats why many stars never become neutron stars, stopping at white dwarfs are other things.

 

The answer is sort of subtle, and involves the fact that electrons in a white dwarf obey fermi statistics (as do neutrons in a neutron star). What this means is that, due to the Pauli exlcusion principle, electron energy levels in the neutron stars fill from the bottom up. What happens because of these statistics is that electrons that sit at low energy levels can only change state if they get enough energy to jump all the way to the top, which almost never happens. So the only electrons free to move about, as it where, are those within a width kbT (T is the temperature of the star) of the last filled energy level. All of the other electrons are trapped in one state. It becomes entropically favorable to form neutrons because it allows more particles to move about, so to speak.

-Will

[infamous]

It becomes entropically favorable to form neutrons because it allows more particles to move about, so to speak.

-Will

OK; and what this is telling us is, that because these particles are more free to move about, Entropy has increased. I think I can understand it from that point of view. Just because a system appears to be more ordered this appearence may not necessarily be factual. So taking this "orderly information", little pun there, we must conclude that Gravity and Entropy follow the same arrow of time. Would this be a correct statement?

[Erasmus00]

OK; and what this is telling us is, that because these particles are more free to move about, Entropy has increased. I think I can understand it from that point of view. Just because a system appears to be more ordered this appearence may not necessarily be factual. So taking this "orderly information", little pun there, we must conclude that Gravity and Entropy follow the same arrow of time. Would this be a correct statement?

 

I think the most accurate way to put things is that in a closed system, entropy always increases, wether the system interacts via gravity, electromagnetic forces, or nuclear forces. The beautiful thing about thermodynamic laws is that the specific mechanism of interaction is largely irrelevant to the behavior of very large systems.

-Will