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Author | Topic: Thermodynamics and The Universe | ||||||||||||||||||||||||
Percy Member Posts: 22391 From: New Hampshire Joined: Member Rating: 5.2 |
Hoot Mon writes: There is no doubt that the expressions of genes, manifesting in phenotypes, produce much more entropy than equivalent weights of minerals bound up in rocks. No doubt? There is every doubt. Calculating entropy changes for complex non-homogeneous materials is incredibly complicated. A simple counterexample to "expressions of genes...produce much more entropy than...rocks" is a seed growing into a tree. While such growth is extremely complicated, we know that the tiny seed system with only a little stored chemical energy and information has changed to become a large tree system with a huge amount of stored chemical energy, and more information, too, though not genetic. --Percy
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Son Goku Inactive Member |
Remember entropy is not fundamentally related to disorder. There are many cases where one can have two systems, the most disorderly of which actually has lower entropy than the ordered one.
Also the measure of entropy, as originally conceived by Boltzmann, depends on exactly where you draw your macro/microstate boundary. Entropy is more a measure of how generic a macrostate is. However a lot of "disordered" states are very generic and hence the link.
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Fosdick  Suspended Member (Idle past 5500 days) Posts: 1793 From: Upper Slobovia Joined: |
Percy wrote:
I was only supposing that genetic expressions in manure amount to greater information/entropy production than the lifeless rocks. Calculating entropy changes for complex non-homogeneous materials is incredibly complicated. A simple counterexample to "expressions of genes...produce much more entropy than...rocks" is a seed growing into a tree. While such growth is extremely complicated, we know that the tiny seed system with only a little stored chemical energy and information has changed to become a large tree system with a huge amount of stored chemical energy, and more information, too, though not genetic. This of course brings into question the meaning of "information" contained in water and rocks verses that contained in living systems. According to information theory, more order means less information, so thermodynamic entropy and information can be equated for theoretical purposes. An information theorist would say that the freezing of water amounts to a loss of information, owing to the reduction of uncertainty in microstate/macrostate networks of communication. Genes are communicators in biosystems, which also maintain high states of order (complexity?). But living systems are dissipative structures, according to Prigogine, and things behave differently when operating "far from equilibrium." Such dissipative structures are disproportionately greater entropy/information producers because they operate far form equilibrium at much high energy costs. This is why manure should produce much more entropy and information that a rock of an equivalent size. ”HM
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Percy Member Posts: 22391 From: New Hampshire Joined: Member Rating: 5.2 |
I understand the point you're trying to make, but you're going to have to consider much more simple and homogeneous objects than manure and rocks in order to be certain of your answer. How much information is contained in 97 billion nearly identical copies of a microorganism? Is your rock homogeneous or does it consist of many different elements and crystalline structures, or does it contain significant amounts of radioactive elements?
Though I was originally replying to Buzsaw and his manure example, I also have in mind what you said back in Message 94, that "Earth has a great deal more entropy production than Mars or Venus, because dissipative structures (e.g., bacteria) produce considerably more entropy than non-dissipative structures (e.g., rocks)..." But what you're doing is drawing conclusions about apples from an example about oranges. In the short term, whether the entropy in a recent cowpat is increasing or decreasing is an extremely complicated and probably unanswerable question. In the long term I'd have to concede it very likely that considered as isolated systems a pound of cowpat began with lower entropy than a pound of, say, granite, but planets that orbit active suns are not isolated systems. If a cowpat has lower entropy than a rock, it still tells you nothing about whether earth is currently gaining or losing entropy. The sun is pouring energy onto the earth, and whether it results in net entropy gains or losses at this point in time I don't think anyone knows. Certainly in the long term, billions of years, earth will experience huge entropy gains, but right now, who knows? The reason I'm quibbling over this is because Buzsaw seems to believe that we can know whether entropy is increasing or decreasing for something the size of a planet. My point is that entropy change is very difficult to determine even with something as simple as a cowpat (especially while the microorganisms are still active), let alone a planet. --Percy
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jar Member (Idle past 394 days) Posts: 34026 From: Texas!! Joined: |
How would you describe the relative "entropy" levels of the following?
Aslan is not a Tame Lion
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Fosdick  Suspended Member (Idle past 5500 days) Posts: 1793 From: Upper Slobovia Joined: |
jar wrote:
That should be fairly easy. Just tell me the file size in kilobytes of each picture. The larger the file the more information it contains, and, corrspondingly, the more entropy it represents. How would you describe the relative "entropy" levels of the following? (5 photos follow) ”HM Edited by Hoot Mon, : No reason given.
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jar Member (Idle past 394 days) Posts: 34026 From: Texas!! Joined: |
Sorry, but I was referring to to the objects the pictures represented.
Aslan is not a Tame Lion
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cavediver Member (Idle past 3643 days) Posts: 4129 From: UK Joined: |
The larger the file the more information it contains, and, corrspondingly, the more entropy it represents That's making some very large (and probably incorrect) assumptions concerning compression techniques.
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Fosdick  Suspended Member (Idle past 5500 days) Posts: 1793 From: Upper Slobovia Joined: |
Percy wrote:
Of course the point of comparing manure to rocks is that manure actively produces more entropy through its microbial metabolism than a rock (of equivalent size) does by way of its internal chemistry and radiation (unless perhaps the rock is a concentrated uranium ore or somethinmg like that). The entropy production of 97 billion identical microbes in manure should make the difference when compared to a rock of equal size without as many bugs.
I understand the point you're trying to make, but you're going to have to consider much more simple and homogeneous objects than manure and rocks in order to be certain of your answer. How much information is contained in 97 billion nearly identical copies of a microorganism? Is your rock homogeneous or does it consist of many different elements and crystalline structures, or does it contain significant amounts of radioactive elements? Though I was originally replying to Buzsaw and his manure example, I also have in mind what you said back in Message 94, that "Earth has a great deal more entropy production than Mars or Venus, because dissipative structures (e.g., bacteria) produce considerably more entropy than non-dissipative structures (e.g., rocks)..." But what you're doing is drawing conclusions about apples from an example about oranges.
To some degree, yes.
In the short term, whether the entropy in a recent cowpat is increasing or decreasing is an extremely complicated and probably unanswerable question. In the long term I'd have to concede it very likely that considered as isolated systems a pound of cowpat began with lower entropy than a pound of, say, granite, but planets that orbit active suns are not isolated systems. If a cowpat has lower entropy than a rock, it still tells you nothing about whether earth is currently gaining or losing entropy.
I don't know how a pound of manure could begin with lower entropy than a pound of rock. A pile of manure can be so thermodynamically energetic it catches on fire, but a pile of rocks usually does not have such a combustible nature.
The sun is pouring energy onto the earth, and whether it results in net entropy gains or losses at this point in time I don't think anyone knows. Certainly in the long term, billions of years, earth will experience huge entropy gains, but right now, who knows?
Yes, the macroscopic aspects of this issue are relevant. I don't know exactly how they could be sorted out. But one thing is certain: Earth is covered with life; her seas a chuck full of it, her land masses, too. All that bio-entropy ought to count for something when comparing the "macro-entropy" of Earth with that of other planets. ”HM
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Fosdick  Suspended Member (Idle past 5500 days) Posts: 1793 From: Upper Slobovia Joined: |
jar wrote:
And the question was, "How would you describe the relative "entropy" levels of the following?" Sorry, but I was referring to to the objects the pictures represented.But all you provide for analysis are 2-D photographs of landscapes. Could you tell me something about the microbial life in those surface photos. If these photos are of Earth's surface then try using a filter that blocks out everything but DNA molecules (assuming, of course, that this is possible). I would expect to see each photo in silhouette form of its original, because on Earth just about everything is cover and/or saturated with DNA molecules, which belong mostly to microbial life. ”HM
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Fosdick  Suspended Member (Idle past 5500 days) Posts: 1793 From: Upper Slobovia Joined: |
The larger the file the more information it contains, and, corrspondingly, the more entropy it represents.
cavediver observes: That's making some very large (and probably incorrect) assumptions concerning compression techniques. ”HM
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ringo Member (Idle past 411 days) Posts: 20940 From: frozen wasteland Joined: |
Hoot mon writes: A pile of manure can be so thermodynamically energetic it catches on fire, but a pile of rocks usually does not have such a combustible nature. Hmm.... When I was a kid, we used to burn rocks in the kitchen stove. Help scientific research in your spare time. No cost. No obligation. Join the World Community Grid with Team EvC
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Percy Member Posts: 22391 From: New Hampshire Joined: Member Rating: 5.2 |
Hoot Mon writes: Of course the point of comparing manure to rocks is that manure actively produces more entropy through its microbial metabolism than a rock (of equivalent size) does by way of its internal chemistry and radiation (unless perhaps the rock is a concentrated uranium ore or somethinmg like that). The entropy production of 97 billion identical microbes in manure should make the difference when compared to a rock of equal size without as many bugs. You're still using an example orthogonal to your point, so let me try again, this time explaining in a slightly different way. If you separately isolate a cowpat and a rock so that each is an isolated system, then I concede it very likely that as time goes by the cowpat will experience a larger increase in entropy than the rock, assuming the rock isn't of some interesting material. But you're using this example to make a point about the earth, and the earth is not an isolated system. So to make your example relevant we have to consider a cowpat and a rock in situations where they, too, are not isolated. So we have to consider something more like the situation the earth is in, such as a cowpat and a rock sitting in a field. The sun is beating down on them during the day. Are they gaining or losing entropy? Beats me, and probably everyone else, too. Do undigested seeds embedded in the cowpat that begin to grow count? Do microbes that fall onto it from the air count? Fly larvae? Do microbes that somehow make a living off rock count? A planet is far more complex. Is the earth gaining or losing entropy right now? Who knows!
I don't know how a pound of manure could begin with lower entropy than a pound of rock. A pile of manure can be so thermodynamically energetic it catches on fire, but a pile of rocks usually does not have such a combustible nature. This reads like you've got the definition of entropy backwards.
Yes, the macroscopic aspects of this issue are relevant. I don't know exactly how they could be sorted out. But one thing is certain: Earth is covered with life; her seas a chuck full of it, her land masses, too. All that bio-entropy ought to count for something when comparing the "macro-entropy" of Earth with that of other planets. Let me get this straight. You feel that some significance can be attached to whether the earth is changing entropy at rates different from other planets, but you don't know whether it is changing at a faster or slower pace, or even whether the change is in a positive or negative direction. Whatever the actual situation turns out to be, since we don't know what the situation is at this point it neither supports nor negates your point. Referring back again to your Message 94, now I'm beginning to wonder if you *are* misunderstanding the nature of entropy. I'm looking at this:
The collective entropy in Earth's biosphere should be computable, via Prigogine, and any life-supporting planet should have measurably higher amounts of entropy than others of equal size that are lifeless. I originally assumed you misspoke and meant to say that any life-supporting planet should have measurably higher rates of increasing entropy, but in this last message you've repeated this. The raw materials of life mixed up and compressed into a rock have much *higher* levels of entropy than the same materials realized as a large colony of bacteria. Life is highly ordered and hence has *lower* entropy. --Percy
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1.61803 Member (Idle past 1503 days) Posts: 2928 From: Lone Star State USA Joined: |
delta s=0 is where the buck stops.
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Fosdick  Suspended Member (Idle past 5500 days) Posts: 1793 From: Upper Slobovia Joined: |
Percy wrote:
Would you expect to see more entropy produced by a one-milligram bacterium or by a one-milligram grain of sand? Since the bacterium is a dissipative structure and the sand grain is not I would expect to see more entropy produced by the bacterium.
This reads like you've got the definition of entropy backwards. I originally assumed you misspoke and meant to say that any life-supporting planet should have measurably higher rates of increasing entropy, but in this last message you've repeated this. The raw materials of life mixed up and compressed into a rock have much *higher* levels of entropy than the same materials realized as a large colony of bacteria. Life is highly ordered and hence has *lower* entropy.
Highly ordered as a dissipative structure, which is a high-rate entropy producer. And remember, a living dissipative structure must dissipate more than just thermodynamic entropy; it must also dissipate digital information through it communication nettworks. ”HM
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