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Could you help me understand what it means to "pump entropy out of a system"? I asked ChatGPT and it claims "It is generally not possible to "pump" entropy out

Could you help me understand what it means to "pump entropy out of a system"? I asked ChatGPT and it claims "It is generally not possible to "pump" entropy out of a system in the same way that it can be added to a system. This is because the second law of thermodynamics states that the total entropy of a closed system will always tend to increase over time."

samus 4y ago
"Pumping entropy out of a system" to me means keeping the system more orderly. To drive such processes, you have to increase entropy elsewhere, which is also known as using energy.
monkeydreams 4y ago
Wouldn't the star itself be the closed system? Any lifeforms within it are free to reduce their own entropy so long as they increase entropy within the system.
- nextaccountic 4y ago
  The star is constantly sending stuff outside (solar wind and light / photons)
- Sharlin 4y ago
  A star, of course, is itself almost as far from a closed system as it is possible to be in our universe. A bomb calorimeter in a chemistry class might be approximated as a closed system for the purposes of thermodynamics. Very few things in nature can.
nextaccountic 4y ago
ChatGPT is wrong here because in order to "pump" entropy out of a system this system must not be closed! So to ask it, you must insist the system isn't closed. And, specifically, living organisms can't be closed systems, because their existence depend on spending energy to decrease their internal entropy, increasing the entropy of the external environment in the process, in order to keep their own entropy low enough to still function without random breakage we would expect from an aging system. And we all know that entropy always wins in the end, and we always break if we are old enough, so this is a sisyphean task; but we still do it all day every day, because we are afraid to die. Anyway, https://en.wikipedia.org/wiki/Entropy_and_life https://en.wikipedia.org/wiki/Entropy_and_life
mtlmtlmtlmtl 4y ago
As usual ChatGPT is only half right. The sun is not a closed system.
- idiotsecant 4y ago
  I disagree, I think it's a case of the question being asked imprecisely. When you ask the right question chatGPT gives you a very insightful and accurate answer. Human : By what means might entropy be pumped out of one part of a system and into another part? ChatGPT: There are several ways that entropy can be transferred from one part of a system to another: Heat transfer: Entropy can be transferred from a hotter body to a cooler body through heat conduction, convection, or radiation. Work: Entropy can be transferred from a system to its surroundings when work is done on the system. Mass transfer: Entropy can be transferred from a system to its surroundings through the transfer of matter. Information transfer: Entropy can be transferred from a system to its surroundings through the transfer of information. Chemical reactions: Entropy can be transferred from a system to its surroundings through chemical reactions, either through the production of heat or through the transfer of matter. Electrical currents: Entropy can be transferred from a system to its surroundings through electrical currents. Magnetic fields: Entropy can be transferred from a system to its surroundings through the generation of magnetic fields. Gravitational fields: Entropy can be transferred from a system to its surroundings through the generation of gravitational fields.
  - mtlmtlmtlmtl 4y ago
    If the person knew how to ask the question "correctly", they wouldn't need to ask. They asked about systems, not closed systems. ChatGPT just regurgitated the 2nd law, which is just plain wrong no matter how you slice it. Any physicist asked this question would explain the distinction.
    - idiotsecant 4y ago
      In the context of this question, system has a specific technical meaning though. This is a very technical question so chatGPT might be forgiven for assuming the technical meaning.
jerf 4y ago
It's a bit of a colloquialism, I think, but the idea is, all of your biological processes are constantly generating entropy.It is constantly tending toward a system in equilibrium, as physical systems do, but you are essentially made out of non-equilibrium systems. You need the water to be here, but not there. Your nervous system is based on electrical gradients that, left to their own devices, will normalize. Every cell has an electric potential gradient it maintains (google "cell proton gradient"). All of these things and thousands more are constantly breaking down and require energy to maintain. Basically, imagine the difference between a recently dead body that just attained ambient temperature and a living one. Characterizing all those differences would be more than the work of a lifetime. A super abstract, but physically valid, way of expressing that is that your body is constantly "generating entropy" and it needs to consume energy to fight it. "Pumping out that entropy" is what the body is doing when it takes in energy and uses it to maintain all those gradients. Life in general may not use organic chemistry, or chemistry at all, but the advantage of this level of abstraction is that any life form (in this universe) will have to do something to "pump out the entropy". It is essentially by definition a deviation from the equilibrium state around it, and it will require energy to maintain. The point I am making here is that there must be some ability to pump out the entropy faster than it is being generated, or pushed in to the system. Otherwise those gradients and variations from equilibrium will be erased. Inside a sun, there is so much heat energy being pressed in to the system that it is challenging to imagine how any conceivable structure could push it back out again. This boils down to the observation that "Holy cow, the sun is, like, REALLY HOT!", but, you know, wrapped up in a different formalism that allows us to get past "But what if, like, there's something that could deal with that?". You see this online, the challenge that someone needs to prove that there's no way to build something that could live in the sun. If you don't have thermodynamics as a tool, this isn't even necessarily unreasonable. But thermodynamics gives us a principled way to turn around and say "Any such system would have to have this and that and the other property, and it's really hard to see how plasma and magnetic fields in such a violent environment could have that." It's so not-close that it's not really plausible. ChatGPT may be referring to the general conceptual space/idea that you can't just build a machine to "reverse entropy" trivially. The most common example of this is that you can't just build an anti-microwave, that remotely cools things by shooting radiation at it in some easy manner. It is sooooo much easier to add entropy than remove it; that is definitely true. In fact, it's kinda a key element of my point here. But you can pump entropy out of a system, in some ways, with some machines, in some manners; since you are literally such a machine yourself, you are an existence proof of that.
trenchgun 4y ago
It's time to stop with the god damn ChatGPT spam in HN comments! https://www.youtube.com/watch?v=2k0SmqbBIpQ https://www.youtube.com/watch?v=2k0SmqbBIpQ

samus 4y ago

"Pumping entropy out of a system" to me means keeping the system more orderly. To drive such processes, you have to increase entropy elsewhere, which is also known as using energy.

monkeydreams 4y ago

Wouldn't the star itself be the closed system? Any lifeforms within it are free to reduce their own entropy so long as they increase entropy within the system.

nextaccountic 4y ago
The star is constantly sending stuff outside (solar wind and light / photons)
Sharlin 4y ago
A star, of course, is itself almost as far from a closed system as it is possible to be in our universe. A bomb calorimeter in a chemistry class might be approximated as a closed system for the purposes of thermodynamics. Very few things in nature can.

nextaccountic 4y ago

ChatGPT is wrong here because in order to "pump" entropy out of a system this system must not be closed! So to ask it, you must insist the system isn't closed. And, specifically, living organisms can't be closed systems, because their existence depend on spending energy to decrease their internal entropy, increasing the entropy of the external environment in the process, in order to keep their own entropy low enough to still function without random breakage we would expect from an aging system. And we all know that entropy always wins in the end, and we always break if we are old enough, so this is a sisyphean task; but we still do it all day every day, because we are afraid to die. Anyway, https://en.wikipedia.org/wiki/Entropy_and_life https://en.wikipedia.org/wiki/Entropy_and_life

mtlmtlmtlmtl 4y ago

As usual ChatGPT is only half right. The sun is not a closed system.

idiotsecant 4y ago
I disagree, I think it's a case of the question being asked imprecisely. When you ask the right question chatGPT gives you a very insightful and accurate answer. Human : By what means might entropy be pumped out of one part of a system and into another part? ChatGPT: There are several ways that entropy can be transferred from one part of a system to another: Heat transfer: Entropy can be transferred from a hotter body to a cooler body through heat conduction, convection, or radiation. Work: Entropy can be transferred from a system to its surroundings when work is done on the system. Mass transfer: Entropy can be transferred from a system to its surroundings through the transfer of matter. Information transfer: Entropy can be transferred from a system to its surroundings through the transfer of information. Chemical reactions: Entropy can be transferred from a system to its surroundings through chemical reactions, either through the production of heat or through the transfer of matter. Electrical currents: Entropy can be transferred from a system to its surroundings through electrical currents. Magnetic fields: Entropy can be transferred from a system to its surroundings through the generation of magnetic fields. Gravitational fields: Entropy can be transferred from a system to its surroundings through the generation of gravitational fields.
- mtlmtlmtlmtl 4y ago
  If the person knew how to ask the question "correctly", they wouldn't need to ask. They asked about systems, not closed systems. ChatGPT just regurgitated the 2nd law, which is just plain wrong no matter how you slice it. Any physicist asked this question would explain the distinction.
  - idiotsecant 4y ago
    In the context of this question, system has a specific technical meaning though. This is a very technical question so chatGPT might be forgiven for assuming the technical meaning.

jerf 4y ago

It's a bit of a colloquialism, I think, but the idea is, all of your biological processes are constantly generating entropy.It is constantly tending toward a system in equilibrium, as physical systems do, but you are essentially made out of non-equilibrium systems. You need the water to be here, but not there. Your nervous system is based on electrical gradients that, left to their own devices, will normalize. Every cell has an electric potential gradient it maintains (google "cell proton gradient"). All of these things and thousands more are constantly breaking down and require energy to maintain. Basically, imagine the difference between a recently dead body that just attained ambient temperature and a living one. Characterizing all those differences would be more than the work of a lifetime. A super abstract, but physically valid, way of expressing that is that your body is constantly "generating entropy" and it needs to consume energy to fight it. "Pumping out that entropy" is what the body is doing when it takes in energy and uses it to maintain all those gradients. Life in general may not use organic chemistry, or chemistry at all, but the advantage of this level of abstraction is that any life form (in this universe) will have to do something to "pump out the entropy". It is essentially by definition a deviation from the equilibrium state around it, and it will require energy to maintain. The point I am making here is that there must be some ability to pump out the entropy faster than it is being generated, or pushed in to the system. Otherwise those gradients and variations from equilibrium will be erased. Inside a sun, there is so much heat energy being pressed in to the system that it is challenging to imagine how any conceivable structure could push it back out again. This boils down to the observation that "Holy cow, the sun is, like, REALLY HOT!", but, you know, wrapped up in a different formalism that allows us to get past "But what if, like, there's something that could deal with that?". You see this online, the challenge that someone needs to prove that there's no way to build something that could live in the sun. If you don't have thermodynamics as a tool, this isn't even necessarily unreasonable. But thermodynamics gives us a principled way to turn around and say "Any such system would have to have this and that and the other property, and it's really hard to see how plasma and magnetic fields in such a violent environment could have that." It's so not-close that it's not really plausible. ChatGPT may be referring to the general conceptual space/idea that you can't just build a machine to "reverse entropy" trivially. The most common example of this is that you can't just build an anti-microwave, that remotely cools things by shooting radiation at it in some easy manner. It is sooooo much easier to add entropy than remove it; that is definitely true. In fact, it's kinda a key element of my point here. But you can pump entropy out of a system, in some ways, with some machines, in some manners; since you are literally such a machine yourself, you are an existence proof of that.

trenchgun 4y ago

It's time to stop with the god damn ChatGPT spam in HN comments! https://www.youtube.com/watch?v=2k0SmqbBIpQ https://www.youtube.com/watch?v=2k0SmqbBIpQ