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Thread: Towards a Maxwell Demon space propulsion system

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    Towards a Maxwell Demon space propulsion system

    Out in space there are ions both near static and highly dynamic.
    (Voyager has encountered them).
    So an artificial tree cloud has a tree like structure with distributed leaves that are maintained by a central trunk. The leaves are either positively or negatively charged and can be switched by the controller in the trunk.
    There are conductors forming ring capacitors concentric with the trunk.
    There are ring anodes and cathodes, similarly.
    These are central concentric rings providing a thrust axis.
    Lesser twig rings are for attitude control.

    In collection mode, incoming particles are captured by electrostatic attraction on the leaves.
    In transfer mode, the incoming charges are stored in ring capacitance.
    In thrust mode the charges and ions are accelerated by voltage gradients in a preferred direction.

    This cloud engine uses incoming energy from stars and distributed charge, and organises it to produce thrust.
    It is a Maxwell Demon but has an energy input all the time.

    So, has this been proposed before?
    sicut vis videre esto
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    Bump!

    So to achieve useful levels of thrust using only collected energy from starlight, this structure would have to be roughly the volume of the Earth's Moon?

    Much more if you want to carry a payload, of course.

    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Quote Originally Posted by Noclevername View Post
    Bump!

    So to achieve useful levels of thrust using only collected energy from starlight, this structure would have to be roughly the volume of the Earth's Moon?

    Much more if you want to carry a payload, of course.

    Well firstly it collects charges, not light, not enough light out there but a sea of charges. Secondly it is scale independent if its charge collector filaments scale with mass. The point is it can travel in the interstellar medium we normally call space. No use for people but given time it will reach stars and planets. But you are right, I would make it quite large and make it grow like a directed crystal pancake, a few miles across.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by Noclevername View Post
    Bump!

    So to achieve useful levels of thrust using only collected energy from starlight, this structure would have to be roughly the volume of the Earth's Moon?

    Much more if you want to carry a payload, of course.

    Any thrust is useful. If its thrust to mass is one Newton per 100 kg, it travels at about 300,000 m/s after a year. It would zip across space near light speed and would have to reverse thrust when approaching another star.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by profloater View Post
    If its thrust to mass is one Newton per 100 kg, it travels at about 300,000 m/s after a year.
    Unless it's in a solar system it might never approach that level. Starlight is very thin on the ground in interstellar space, and the ISM is especially thin in the Local Bubble. It's really only practical as an in-system drive where sunlight and stellar wind can be of use.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Quote Originally Posted by Noclevername View Post
    Unless it's in a solar system it might never approach that level. Starlight is very thin on the ground in interstellar space, and the ISM is especially thin in the Local Bubble. It's really only practical as an in-system drive where sunlight and stellar wind can be of use.
    I think you forget the ions encountered by Voyager 1 and 2 . This is not a light system. Space is full of charged particles. The faster you go, the more you encounter. The charge being organised by technology is the energy source and the ions are the propellant.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    I actually remember seeing the original post but didn't answer, basically because I simply don't understand what is being described or how it works. It might just be insufficient knowledge on my part to understand it. Maybe other people had the same experience, though perhaps people with a good electrical background might have insights.
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    Quote Originally Posted by profloater View Post
    I think you forget the ions encountered by Voyager 1 and 2 . This is not a light system. Space is full of charged particles. The faster you go, the more you encounter. The charge being organised by technology is the energy source and the ions are the propellant.
    OK. Have the numbers been crunched on how much/how fast?
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Quote Originally Posted by Noclevername View Post
    OK. Have the numbers been crunched on how much/how fast?
    No, but I am describing a principle. The density of ions in space as observed by Voyager, well outside the solar system now, is in the order of several per cubic centimetre. The particles originate in the big bang story of stars and so on.

    The point of intelligent technology is that we can manipulate charge. The Maxwell Demon part is that we can separate plus from minus and accumulate it like the brilliant Wimshurst machine. The energy stored in the vacuum of space can be collected and directed to run a controller and produce thrust. Those are established technologies. Charge accumulation, electronic switches, electrostatic acceleration, plus magnetic effects to have a field way bigger than the device to suck in charged particles.

    If it is easier to imagine, make the device two units, one attracting positive charged particles and the companion, negative. The charge drives a current and already there is enough to form an engine. Space is the fuel. Not an empty vacuum but a space filled with potential energy.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by Jens View Post
    I actually remember seeing the original post but didn't answer, basically because I simply don't understand what is being described or how it works. It might just be insufficient knowledge on my part to understand it. Maybe other people had the same experience, though perhaps people with a good electrical background might have insights.
    I don't understand it either, but it sounds like a perpetual energy machine; I can't imagine how it could work. You need energy to keep a charge on the "leaves". A positively charged leaf will collect negative ions, but will become less positive until it is neutral. Where does the energy come from to keep it positively charged?

    In thrust mode you have you accelerate the particles with a voltage gradient - again you need energy to generate the gradient.

    Unless - is this device just a way to collect "fuel", but not generate energy? Is this basically just an ion thruster, but you are collecting the fuel from space? Reminds me of a Bussard ramjet. That might work, thought I'm not sure the density of particles in space is worth the effort.
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    Other considerations aside, the very interstellar medium you are using for an energy source and as propellant will impose drag on the device. This issue has long since been identified as a significant flaw in the concept of the Bussard Ramjet that renders the concept unworkable. Given that the Bussard Ramjet utilizes fusion, which would seem to get much more energy out of a given amount of interstellar medium than this proposed device could be capable of, and yet it won't work because of drag, my guess is that this concept is also unworkable due to drag or that, at a minimum, it would not be capable of attaining relativistic speeds.

    Of course, even if it was slow but otherwise did work it could still be very useful.

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    Profloater and Noclevername seem to understand the concept, so perhaps one of them could explain in more detail how this would work.


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    Quote Originally Posted by Jens View Post
    Profloater and Noclevername seem to understand the concept, so perhaps one of them could explain in more detail how this would work.
    It's PF's idea, I'll let them describe it.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    It does sound like another way to accomplish the same thing as a Bussard Ramjet, except far heavier and more complicated due to using many small physical "scoops" as opposed to one big magnetic field and all the other intermediate stuff.

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    Quote Originally Posted by Swift View Post
    I don't understand it either, but it sounds like a perpetual energy machine; I can't imagine how it could work. You need energy to keep a charge on the "leaves". A positively charged leaf will collect negative ions, but will become less positive until it is neutral. Where does the energy come from to keep it positively charged?

    In thrust mode you have you accelerate the particles with a voltage gradient - again you need energy to generate the gradient.

    Unless - is this device just a way to collect "fuel", but not generate energy? Is this basically just an ion thruster, but you are collecting the fuel from space? Reminds me of a Bussard ramjet. That might work, thought I'm not sure the density of particles in space is worth the effort.
    All good points. The drag will be an issue as speed increases because a magnetic field has to arranged to capture ions so there is a momentum change. this might be a perpetual motion device , it organises the charges encountered then uses them. If a positive leaf attracts electrons toward zero charge, that is a current into the leaf. But if the organisation needs work…

    There is an assumption that there is a distribution of charge, ie electrons and electron holes, and these do not just cancel into atoms because of the free path in vacuum.. i know there has been a fusion suggestion by Bussart and others but fusion is so difficult. This is just charge based.

    I mentioned Wimshurst, his machine generates charge by motion so it takes in work, but he then accumulated charge up to thousands of volts. If you are sailing through a sea of plus and minus charges, you need to separate them. Semiconductors take the place of the spinning wheels of Wimshurst.

    (Although for visualisation you can imagine an insulator collecting charge and transfering it mechanically to a capacitor as Wimshurst did.)

    The input energy is the potential energy of opposed charges. One captured you let them combine as a current in wires. That current can be used to do work. The nature of the work is to eject some of the charged ions in one direction to make thrust. Like any ion engine, that limits actual speed.

    This is not for human travel, but a machine that can go for aeons using the particles it encounters. Of course if there are no charged particles, just atoms, then it cannot work. But I get the impression there are charges to be mined in this way.

    I realise now that a funnel collecting particles and bringing them together until they attract each other to release potential energy is the same concept and it is no use if you have to do the work equivalent to make them move. That is the Maxwell Demon element.

    If you cannot separate them out by information, then this was a waste of time and thought, and I apologise. Where is Maxwell’s Demon when you need him/her.?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by Noclevername View Post
    It's PF's idea, I'll let them describe it.
    But you wrote:
    So to achieve useful levels of thrust using only collected energy from starlight, this structure would have to be roughly the volume of the Earth's Moon?
    How did you come up with that question? I didn't even understand enough to understand how big the structure would have to be.
    As above, so below

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    Quote Originally Posted by Jens View Post
    But you wrote:


    How did you come up with that question? I didn't even understand enough to understand how big the structure would have to be.
    Well, according to the OP description, it has to use particles in the Interstellar Medium, the hardest vacuum that humanity has access to. It would therefore need a great many ions to thrust as described, meaning a huge surface area of "leaves" to collect those particles. Much bigger than a light sail but probably placed omnidirectional, not just a 2-dimensional reflector. Also, I was under the impression that it would be powered by photovoltaics from starlight; IIRC that requires collectors as big as most space bodies. But profloater said that's not the case here, which means the ion collection has to do double duty as both a thrust propellant and a power source, so it has to be even bigger.

    In any case, I believe it would be impractical as a working interstellar drive. You'd get some motion, but very slow due to the extremely low energy and matter density of the medium.
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    Quote Originally Posted by Noclevername View Post
    In any case, I believe it would be impractical as a working interstellar drive. You'd get some motion, but very slow due to the extremely low energy and matter density of the medium.
    I think you're probably right about that, but honestly I didn't even understand how the system would work in the first place.
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    profloater, you said you would not use stellar light in your vessel. But it should be significantly stronger energy than the ISM. Would you consider it as a viable power source?
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    Quote Originally Posted by profloater View Post
    <snip>
    I realise now that a funnel collecting particles and bringing them together until they attract each other to release potential energy is the same concept and it is no use if you have to do the work equivalent to make them move. That is the Maxwell Demon element.

    If you cannot separate them out by information, then this was a waste of time and thought, and I apologise. Where is Maxwell’s Demon when you need him/her.?
    A Maxwell's Demon by its nature violates the 2nd Law of Thermodynamics. I'm not an expert on the topic, but I believe there have been some quantum scale devices that function in some ways like such a thing, but nothing macroscopic, nor something that creates more energy than it uses.
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    Quote Originally Posted by Noclevername View Post
    profloater, you said you would not use stellar light in your vessel. But it should be significantly stronger energy than the ISM. Would you consider it as a viable power source?
    It is at least an incoming energy! It was the ramjet effect of particles that got me started, you do not get that with light. If the particles were hydrogen and oxygen, you could collect them and reap chemical energy. But those are rare!

    Every time a photon hits one of these particles in the vacuum it can kick an electron into higher energy, later to be released again. But to harness that you need an even colder sink. Unfortunately my demon is energy hungry too.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by Swift View Post
    A Maxwell's Demon by its nature violates the 2nd Law of Thermodynamics. I'm not an expert on the topic, but I believe there have been some quantum scale devices that function in some ways like such a thing, but nothing macroscopic, nor something that creates more energy than it uses.
    Quite so, I wanted to convert the potential energy of the interstellar medium into kinetic energy. Maxwell’s original sat in a box passing only high velocity atoms to one end. for a while I supposed I could put negatives in one collector and positives in the other, by whizzing through them. But that is just a cousin demon. The clue was in my title, but I needed a demon with agency. They seem to live elsewhere.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by profloater View Post
    It is at least an incoming energy! It was the ramjet effect of particles that got me started, you do not get that with light.
    Well, you'd need a power source for any kind of ramjet, at least that's my understanding.

    The ISM particles are too random in their motion to provide any kind of practical propulsive force themselves, and the ions are too thinly distributed to add up to much electromagnetic energy.
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    This concept uses the interstellar medium as a power source.
    The Q-Drive
    https://www.centauri-dreams.org/2020...tellar-flight/
    I don't really understand it, but I think it only works if there is a net flow in the interstellar medium, which may be the case in much of the galaxy. It seems more likely to work on an interplanetary scale, although once again the energy source is small.


    It seems to work on a similar principle to those wind-turbine boats you see sometimes.
    https://www.energy-observer.org/inno...rbine-thruster

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    Quote Originally Posted by Swift View Post
    I don't understand it either, but it sounds like a perpetual energy machine; I can't imagine how it could work.
    The Wikipedia article which describes Maxwell's demon calls it almost exactly that:

    Maxwell's demon is a thought experiment that would hypothetically violate the second law of thermodynamics. It was proposed by the physicist James Clerk Maxwell in 1867.
    On a brief tangent I read a Larry Niven story many years ago which involved a discussion between two wizards. At the time I didn't understand the underlying context of their conversation. The quote below is the entire text of an unfinished story from The Time of the Warlock. So after 35 years since I first read this, the penny has finally dropped.

    As he left the blazing summer heat outside the Warlock's cave, the visiting sorcerer sighed with pleasure.

    "Warlock, how can you keep the place so cool? The mana in this region has decreased to the point where magic is nearly impossible."

    The Warlock smiled and so did the unnoticeable young man who was sorting the Warlock's parchments in a corner of the cave. The Warlock said, "I used a very small demon, Harlaz. He was generated by a simple, trivial spell. His intelligence is low fortunately, for his task is a dull one. He sits at the entrance to this cave and prevents the fast-moving molecules from leaving. The rest he lets pass. Thus the cave remains cool."

    "That's marvelous, Warlock! I suppose the process can be reversed in winter?"

    "Of course."

    "Ingenious."

    "Oh, I didn't think of it," the Warlock said hastily. "Have you met my clerk? It was his idea." The Warlock raised his voice. "Oh, Maxwell...

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    Quote Originally Posted by eburacum45 View Post
    This concept uses the interstellar medium as a power source.
    The Q-Drive
    https://www.centauri-dreams.org/2020...tellar-flight/
    I don't really understand it, but I think it only works if there is a net flow in the interstellar medium, which may be the case in much of the galaxy. It seems more likely to work on an interplanetary scale, although once again the energy source is small.


    It seems to work on a similar principle to those wind-turbine boats you see sometimes.
    https://www.energy-observer.org/inno...rbine-thruster
    Well now it is I feeling confused and must comment on the last analogy, the wind turbine sailing into the wind. This is nothing to do with propellent mass but the reaction effect of the dense water. The energy extracted from the head wind can be converted directly to a prop to propel the boat forwards. I even build one of these in a previous life. It is a gearing effect.

    In that life I won a bet about a light mass transit system using a moving chain in the ground. The cars can go, for example, at twice the chain speed. This is because of friction on the stationary ground. This was a real proposal and I showed that overall friction losses are minimised with the cars going twice the chain speed. The boat example is the same; the energy extracted from the wind relative to the boat is nearly independent of the energy needed to drive the boat in any direction. The Americas cup showed that rather well, albeit with just a sail.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by Swift View Post
    A Maxwell's Demon by its nature violates the 2nd Law of Thermodynamics. I'm not an expert on the topic, but I believe there have been some quantum scale devices that function in some ways like such a thing, but nothing macroscopic, nor something that creates more energy than it uses.
    I looked up the ISM in WP and it is quite complex and “not well understood” Away from stars it does seem to be mostly Hydrogen atoms with just a few ions. Voyager, which set me off thinking, is experiencing ions but that might still be solar induced. By gamma rays. No wonder the idea of a travelling fusion engine was invoked. That would be a real star ship!
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Fusion has its own issues...

    1. We can't make a fusion rocket yet, though it may be less difficult than a contained fusion reactor.
    2. The hydrogen out there is mostly simple Protium, only suited to fusion in conditions of a star's interior.
    3. The atoms and ions are scattered so thin that collecting any decent mass means you already have to be going at Ludicrous Speed to pass through enough of them to be worth a darn. The only alternative is to bring your own fuel, with the mass of a mountain, miles in diameter.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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