• TheQuestion
    58
    If the multiverse or parallel dimensions exist wouldn’t that violate the second law of dynamics?

    Or will it just mean that how we interpret entropy will change because of the possibility of foreign energy being able to be introduced into a encapsulated Universe.

    And entropy will need to be interpreted in a grander scale beyond our native Universe.

    Will this foreign energy behave the same manner in our Universes as compared to it’s own native Universe?

    You would have to assume that the physics in that Universe may differ compared to our own and so entropy may behave differently. Will it still be entropy?

    Just a thought.
  • Miller
    92
    Reality is a perpetual motion machine
  • Nils Loc
    965


    Are you confusing the 1st and 2nd laws of thermodynamics?

    All multiverses belong to the same universe which is undergoing a transition according to the first and second law of thermodynamics. All of the many worlds are winding down while energy is conserved. But I'm no expert.
  • TheQuestion
    58
    First let me say I am trying to understand Entropy and Enthalpy

    What I understand is Enthalpy is the amount of internal energy contained in a compound whereas entropy is the amount of intrinsic disorder within the compound.

    I also know that The first law of thermodynamics, also known as Law of Conservation of Energy, states that energy can neither be created nor destroyed

    I understand that...

    But Entropy doesn’t make sense to me because it contradicts the point of a expanding Universe.

    How can something become more disorganized if there is more space?

    To put it in simple terms. I have a messy room filled with stuff. Stuff being energy, wouldn’t my room automatically become more seemingly organized if the room is expanding? Room being the Universe.

    And another point is If the first law of thermodynamics states you can’t create or destroy energy. That would mean energy is finite. There is only a certain amount of energy in the Universe.

    And Entropy is the result of a expanding Universe with finite energy. Based on my understanding.

    So wouldn’t the multiverse change that perspective because that would mean you can introducing new energy in a encapsulated Universe or at least the possibility of introducing new energy to our Universe.

    And wouldn’t that explain the existence Dark Energy? Dark energy being the unknown energy expanding our Universe.
    And where it came from...

    Also, wouldn’t the multiverse cause problems on how we see a Entropy Universe?

    I have other questions to like, if the Multiverse is proven as true. How will that effect the other theories of physics?

    A good example how energy behaves differently between one Universe compared to another due to the possibility of different laws of physics.

    If we are living in a multiverse are we living in an encapsulated Universe and each Universe has a cosmic membrane or do Universes have no boundaries which in that case one universe can merge with another like two galaxies?

    If there is a cosmic membrane that mean there is an external force that this native Universe is trying to shield itself from. Like a air bubble in water.

    The point is the theory Multiverse would challenge how the laws of thermodynamics is viewed.

    Entropy would not make sense if the Multiverse theory is proven as true.
  • TheQuestion
    58
    Also if there is a Cosmic membrane what is it made of?
  • TheMadFool
    13.7k
    There's something subjective about entropy. The statistical argument for entropy goes like this:

    1. There's only one particular arrangement of particles that interests you. Call it x.

    2. For every x there are a large number of ways in which x is not the case. Call it Y.

    3. Say, x : Y = 1 : 999.

    4. Probabilities:

    The P(x) =

    and

    P(Y) =

    The entropy only increases if x is what you're interested in, right?

    On a die roll, if you want a 3, the P(3) = but if you don't mind whether a 3 or a 5 or a 6 then the probability of getting what you want = .

    My family on my father's side has a stock phrase which is "nothing will happen" which annoys my mother to no end; she interprets that phrase as "it doesn't matter" or "Que Será, Será". :rofl: Women! You can never really understand them! You can f**k 'em though. :rofl:

  • the affirmation of strife
    39
    I'm not brave enough to answer the title with any definitives, but my hunch is "no". To me, it seems like there are quite a few misconceptions in your posts, @TheQuestion. Forgive me for not offering a full tutorial on thermodynamics, but I sugges to watch some videos from the channel "PBS Space Time" on youtube, or even better: find a good book on the subject (I could suggest thermodynamics textbooks but that's likely not what you want). A short and approachable popular science/philosophy book that touches many of these topics is "The Order of Time" by Carlo Rovelli, I can highly recommend this book.
  • TheQuestion
    58
    I am trying to understand Entropy in the most simplest term.

    There is a couple of parts to this that I understand when defining Entropy.

    First Part:
    From what I can understand is that Entropy is a measure of the disorder in a closed system. In other words there is a certain amount of possible variables or X amount of possible mutations that can happen in a closed system.

    Second Part:
    Entropy increases when it gets hotter and decreases when it gets colder. So heat makes the Universe function creating more mutations and when the Universe gets cold it means that the Universe is dying cause there isn't enough Entropy to create more mutations.

    A good analogy is this...

    A customer hires a architect to design a house with X amount of materials. The house that this architect is designing will be a house that is constantly expanding itself. Let's pretend it is an "AI home" that can remodel itself without outside interference. The home can modify the existing rooms at will and can only add a certain amount of rooms due to the limitation of available materials it has. So this "AI home" can only modify itself an X amount of times.

    Materials being energy and the house being the Universe.

    another example:
    If you have 50 pieces of lumber that can only produce 3 rooms and be arrange in 20 different ways. That's it there is no other ways outside those 3 rooms and 20 arrangement ways.

    Like solving a rubik's cube there is only 43,000,000,000,000,000,000 ways to solve it, no more, no less.

    The solution being the amount of mutations that can occur in the Universe or possible amount of creations like planets, stars, blackholes, life, etc.....

    And heat is the motivating factor to cause Entropy to make things. When the Universe expands things get colder and Entropy can't produce more mutations due to the lack of heat. Hence the "Big Crunch theory". But evidence is pointing to more of "The Big Rip Theory" because the Universe is accelerating and it is getting hotter.

    If the Multiverse theory is proven to be true then that would mean a outside force is funneling energy in our Universe causing a rapid expansion. Which may contradict "the first law of thermodynamics" you can't create more energy to make more stuff. It also contradict "the second law of thermodynamics" that only an X amount of mutations can exist in our Universe.


    Either one, we are a bubble ready to pop "The Big Rip theory" or two the Universe will keep expanding forever. Either way is because some one or something is shoving more energy in our bubble Universe to create more stuff.

    If the Multiverse is true than isn't logical to assume that Entropy will become infinite with an infinite amount of possible creations will keep occurring?
  • the affirmation of strife
    39
    when the Universe gets cold it means that the Universe is dying cause there isn't enough EntropyTheQuestion

    Not really like that. I'm not the best person for the job but I'll give it a shot: The weird part about entropy is that it always increases. Decreasing entropy globally is the same as turning back time. Think about it like this: Put a block of ice in a room, it melts, because of the surrounding heat (random particle motion). But the same random particle motion will never cause the block of ice to re-form out of the water vapor in the air. Entropy death of the universe is also called heat death, precisely because it wouldn't be super cold. It would be just "meh", but the point is, temperature would be exactly the same, everywhere. Peak entropy.

    If the Multiverse theory is proven to be true then that would mean a outside force is funneling energy in our Universe causing a rapid expansion.TheQuestion

    I'm pretty sure the "multiverses" in this hypothesis are necessarily independent. No funnelling. Otherwise they are just "bubble universes" inside a bigger universe like @Nils Loc said. AFAIK the multiverse hypothesis doesn't save our universe, just that some kind of universe will always be there. I could be wrong on that.

    And heat is the motivating factor to cause Entropy to make things.TheQuestion

    Note that entropy doesn't produce things, it's just a measure of disorder. Heat can produce things, but only by transforming other things.

    Dark energy is out of my field completely, but it sure is weird. I hope I didn't come off dismissive in my earlier reply, it wasn't my intention. You're asking big questions and I only meant to suggest some resources that I found useful, to the small extent that I've delved into them.
  • SophistiCat
    1.8k
    How can something become more disorganized if there is more space?TheQuestion

    This is why entropy as a measure of disorder isn't always a good metaphor. A textbook example of increasing entropy is a half-evacuated chamber:

    180px-Before_during_after_sudden_expansion.jpg

    When the partition is removed or breached, gas fills the entire chamber. Assuming it does not exchange energy with the environment, the only change here is that the volume occupied by matter increases. Entropy increases because the number of micro-states available to it increases following expansion.

    An expanding universe does not require an adjacent empty space to expand into, since space itself expands, but otherwise it presents a similar case. Expansion means more available configurations - means higher maximum entropy at equilibrium - means steeper entropy gradients on the way towards that equilibrium state - means more interesting dissipative structures like stars and living things forming along the way. Yay expansion!
  • TheMadFool
    13.7k
    Interestingly, the law of thermodynamics, being statistical/probabilistic, contains the seed of its own destruction. Even though the chances of entropy reducing is vanishingly small, it isn't nought!

    :chin: Amazing! A law that, in principle, cannot be violated.

    This was our paradox: no course of action could be determined by a rule, because any course of action can be made out to accord with the rule. — Wittgenstein (rule following paradox)
  • jorndoe
    1.6k
    , or any of the physics folks, a quick question ...

    The expansion of the universe roughly means that mass or matter density decreases over time, matter dilutes, spreads, thins out spatially, apart from what gravity holds together. With entropy, the density tends to "even out".

    Yet, despite the spatial expansion, the quantum energy density remains constant, or the average micro-chaos, in lack of a better term, per spatial unit does not change.

    So, matter dilutes, energy of space itself does not. It's like space isn't "stretching", but rather ehh "growing", in lack of better verbiage.

    (The micro-chaos largely "cancels out", so that we don't see a photon flying off in one direction, and an anti-photon flying off in another, at least not normally, but, also, the background quantum-scale energy isn't exactly zero.)

    That's from memory (i.e. not reliable). Anyway, if I'm remembering right, then I think there might be some implications to how we think of these things, including conservation.
  • Hermeticus
    135
    1. We're not sure if our universe is an isolated system. The second law of thermodynamics may not apply as it is.

    2. If our universe is an isolated system, it would cease to be if it came in contact with a different universe. The second law of thermodynamics would stop to apply as they interacted with each other.


    Thermodynamics in space, as far as I'm aware, still has many questions open. It really depends what the "border" of our universe looks like - a question that we can't even begin to answer. Is there an edge of the universe? If yes, what happens if I attempt to cross the edge? Is it impermeable or can I pass through? If I pass through, do I arrive somewhere or do I cease to exist?
  • Count Timothy von Icarus
    282
    I guess it depends on what type of multiverse you're talking about.

    In the Many Worlds interpretation of quantum mechanics, every possible quantum outcome is physically realized, resulting in an endless multiplication of worlds.

    This would appear to have strong consequences for probabalistic interpretations of entropy:

    With a gas in a box, the probability that all the gas molecules are in one corner of the box at the same time is very small (for a typical box full of 1020 molecules or more, incredibly small): this is therefore a low entropy state. It is much more likely that the molecules are randomly distributed around the box, and are moving in random directions; this high disorder state is a considerably higher entropy state. The second law doesn't rule out all the molecules ending up in one corner, but it means it's far more likely that the molecules will be randomly distributed, and to move towards a random distribution from an orderly distribution, as opposed to the other way around.

    If you take this at the quantum level though, and assume the Many Worlds interpretation, there are series of outcomes where entropy isn't increasing as the universe expands. It seems like you could have a uniform, organized expansion after the Big Bang and thus not have the asymmetry of time as a property of the universe.

    If you're talking about the many universes posited by various anthropic principle claims (https://en.m.wikipedia.org/wiki/Anthropic_principle), then the 2nd Law is probably another of those constants that has to exist in order for observers to form, and for a view of the universe to exist. Without it, you'd have time symmetry and it doesn't seem observers would be possible. There could be universes with different strong and weak nuclear forced, a different speed of light, and static entropy, but they would never produce anyone to observe them and so the question would never get asked.
  • SophistiCat
    1.8k
    The expansion of the universe roughly means that mass or matter density decreases over time, matter dilutes, spreads, thins out spatially, apart from what gravity holds together. With entropy, the density tends to "even out".

    Yet, despite the spatial expansion, the quantum energy density remains constant, or the average micro-chaos, in lack of a better term, per spatial unit does not change.

    So, matter dilutes, energy of space itself does not. It's like space isn't "stretching", but rather ehh "growing", in lack of better verbiage.
    jorndoe

    I am out of my depth here, but as far as I understand, dark energy is what accounts for the expansion of space, which in turn creates more dark energy, and so on. What that does to entropy, beyond the effect of non-equilibrium expansion to which I referred earlier, I cannot say.
  • TheQuestion
    58
    So I may have taken the definition of “entropy” out of context here.

    Also I guess I need to first understand the “Theory of the Multiverse”.

    When I first heard of the Multiverse theory I automatically pictured a bunch of bubble Universes inside a giant single reality.

    And the Big Bang was the product of two membrane Universes banging up against each other creating the singularity or pre- Big Bang. You had the transfer of energy coming from two Universes creating this one.

    Cosmic honeymoon creating an offspring which is this Universe. LOL! Sorry Cosmology joke.

    But if this is evidence of a multiverse than the first law of thermodynamics is not applicable to a Universe.
  • TheQuestion
    58
    My post above is in regards to the “Cold Spot” in our Universe and how it is considered to be possible evidence of the Multiverse.

    Because the “cold Spot” maybe due to another Universe colliding with ours.

    It is to reference a article I read that is why I am posting this topic.

    “The first ever evidence of the Multiverse”
    - Marcia Wendorf
    https://interestingengineering.com/the-first-ever-evidence-of-the-multiverse
  • SophistiCat
    1.8k
    If you take this at the quantum level though, and assume the Many Worlds interpretation, there are outcomes where entropy isn't increasing as the universe expands. It seems like you could have a uniform, organized expansion after the Big Bang and thus not have the asymmetry of time.Count Timothy von Icarus

    You can have that without Many Worlds too. I don't see what Many Worlds adds here. Instead of one timeline you have an ensemble of timelines all subject to the same statistics.
  • SophysFile
    7
    All universes must obey the laws of thermodynamics, i.e, where time moves forward. Be it the many worlds in the MWI or whatever. There could be local reversals of time, like gas collecting in one corner, but these are due to conscious intervention. The initial state can't be such that this occurs later. Only in the very universe there could be local patches were time might seem to run backwards, but these are always embedded in the larger whole of forward time and can't lead to such time reversals in later times. Which is not to say that order can't occur.

    This discussion is often heard in the context of Boltzmann brains. This clearly violates the second law, and in an infinite universe, occupied by homogeneous matter, this should eventually happen. A whole universe could evolve like this. It is said that these fluctuations are temporary, like the local patches of time reversal in the early universe. The point is though that these kinds of local ordering can only appear in the very early universe, to be overtaken by the forward march of time. If they appear later this will need initial fine-tuning, while this fine-tuning is not required for ordered life to appear. All initial random configurations will inevitably lead to life, and any deviation from randomness will be flattened out fast.
  • SophysFile
    7
    Cosmic honeymoon creating an offspring which is this Universe. LOL! Sorry Cosmology joke.

    But if this is evidence of a multiverse than the first law of thermodynamics is not applicable to a Universe.
    TheQuestion

    This process can be repeated over and over. Every time a low entropy can be created from nothing (the two empty parallel branes) from two entropically maximized universe on both branes. Which is similar to two universes forming on two sides of a wormhole, accelerating away from each other, after which two new universes are created (like two branes periodically meeting, residing, approaching, meeting, etc.).
  • Kenosha Kid
    3.1k
    Yet, despite the spatial expansion, the quantum energy density remains constant, or the average micro-chaos, in lack of a better term, per spatial unit does not change.jorndoe

    QFT is valid for flat space-time only. There's no general, relativistic quantum theory, so nothing to say what happens to vacuum energy as the universe expands. Indeed, it is expected to change, but in what direction... ? E.g. https://arxiv.org/abs/1402.7049 compared with theories equating vacuum energy with the inflation field.
  • Manuel
    1.9k
    I am also above my abilities here, but that's never stopped a discussion, so, I'll ask:

    Shouldn't the second law of thermodynamics be called a "habit" instead of a law? It seems to me to speak of a tendency to disorder, not an iron-clad rule.

    We are here after all, so there are pockets or order within disorder, or something.
  • Kenosha Kid
    3.1k
    Shouldn't the second law of thermodynamics be called a "habit" instead of a law? It seems to me to speak of a tendency to disorder, not an iron-clad rule.Manuel

    Hey, if Hooke's law gets to be a law, thermodynamics is a cert!

    Btw , I recall a paper Hawking gave on how multiverses _restore_ the second law, solving the problem of what happens to information about particles destroyed in black holes. Iirc, it's that over an infinite number of universes, the net loss is zero. But don't trust my ability to rc.
  • jorndoe
    1.6k
    , , thanks lots.

    Found something over here:

    Dark energy might be neither particle nor field (Ethan Siegel; Big Think; Sep 22, 2021)

    cxm7xpzllr8hvw45.png

    I guess relativistic spacetime geometry and quantum field theory has no good unification (at the moment at least), but that'd be needed to say much when experimental confirmation/falsification is unavailable.
  • Kenosha Kid
    3.1k
    Also see the hypothetical inflaton field, which has a constant energy despite expanding... EDIT... in a metastable state, and may do in its ground state too.
  • Count Timothy von Icarus
    282


    Right, you could have it, but obviously we don't have it at the macroscopic level, as entropy is observably increasing. However, given many worlds, the almost infinitely improbable universe of non-increasing entropy is one of the (almost?) infinite worlds and actually exists.

    Whereas you as an observer in one world could expand the volume of a container of gas all day for a billion years and not see entropy remain static a single time, because the probability is incredibly low.
  • jorndoe
    1.6k
    , thanks.

    Yet another thing to read (Vacuum energy and cosmological evolution).

    FYI, this stuff came up some time ago while discussing "symmetries" like this:

    zk81ht59ygcogjzi.png

    Things shrinking versus space expanding.
    I haven't done the mathematics or other analysis.

    EDIT ... :-/ the to-read list just keeps on growing ...

    Eternal inflation and its implications (2007)
    Our Universe May Exist in a Multiverse, Cosmic Inflation Discovery Suggests (2014)
    Before the Big Bang 5: The No Boundary Proposal (2017, 50m:47s)
    A smooth exit from eternal inflation? (2018)
  • SophistiCat
    1.8k
    Shouldn't the second law of thermodynamics be called a "habit" instead of a law? It seems to me to speak of a tendency to disorder, not an iron-clad rule.Manuel

    Hey, if Hooke's law gets to be a law, thermodynamics is a cert!Kenosha Kid

    Hey, Einstein field equations are basically a glorified Hooke's law :)

    The second law is a statistical law, so yes, it doesn't deliver absolutely certain predictions. It works well with probabilistic epistemology though: its predictions should be treated as rational expectations. Yes, it is possible for all the air in your room to spontaneously bunch up in one corner, but you should not take that possibility seriously, on account of its vanishingly low probability.

    Right, you could have it, but obviously we don't have it at the macroscopic level, as entropy is observably increasing.Count Timothy von Icarus

    Well, it has been increasing so far, in our corner of the universe...

    However, given many worlds, the almost infinitely improbable universe of non-increasing entropy is one of the (almost?) infinite worlds and actually exists.

    Whereas you as an observer in one world could expand the volume of a container of gas all day for a billion years and not see entropy remain static a single time, because the probability is incredibly low.
    Count Timothy von Icarus

    A thermodynamic anomaly could still happen in our world, for all we know. Thermodynamics describes our expectations of what we are likely to observe, and that is not affected by there being many other worlds, because we are only experiencing one world.

    Besides, you shouldn't conflate the many branches of the universal wavefunction with the many microstates of each and every statistical ensemble described by thermodynamics. There is no one-to-one correspondence between them, since they describe very different things.
  • Kenosha Kid
    3.1k
    Hey, Einstein field equations are basically a glorified Hooke's lawSophistiCat

    I don't see how. The field equations are general (hence "general relativity") which seems a good condition for a 'law'. Hooke's works as long as you don't compress or stretch _too_ much, where "too much" could mean "almost anything" :rofl:

    Yes, it is possible for all the air in your room to spontaneously bunch up in one corner, but you should not take that possibility seriously, on account of its vanishingly low probability.SophistiCat

    Which tbf is now, post quantum theory, true of anything. Individual particles are statistical quantities.

    Yet another thing to read (Vacuum energy and cosmological evolution).jorndoe

    Dat's da same paper!
  • SophistiCat
    1.8k
    I don't see how.Kenosha Kid

    I was kidding, of course. But you could trace the ancestry to the Hooke's law from the stress components of the tensor. I am not sure, but that may have been the first example of a constitutive material equation, which evolved into continuum mechanics, and from there it's a hop, skip and a jump to GR :)
  • jorndoe
    1.6k
    A quick read

    The universe may have answered The Last Question (Nov 13, 2021) by Tim Andersen
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