When do the laws of physics not apply?

Discussion in 'Physics' started by studiot, Feb 17, 2009.

  1. studiot

    studiot Thread Starter E-book Developer

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    We have had several threads lately about such subjects as temperature, entropy , the speed of heat transfer and their connection to statistical and quantum mechanics.

    Some interesting questions were raised which lead to the following one.

    Consider a universe containing a single isolated molecule.

    What would be the temperature, speed and entropy of this molecule?

    Do all the normal laws of physics apply in this universe?
  2. KL7AJ

    KL7AJ E-book Developer

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    They apply everywhere. That's why they're called LAWS of physics. Otherwise, they'd be called "suggestions."

    eric
  3. studiot

    studiot Thread Starter E-book Developer

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    So what is the entropy of this molecule?
  4. thingmaker3

    thingmaker3 Moderator Staff Member

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    If the molecule were the only thing in the little pocket universe, speed would be meaningless. One must have a "here" and a "there" to get distance, and a distance to get distance/time.

    We could, of course, specify a highly radioactive molecule. That way we could, after a random amount of time, have more than one thing and therefore more than one place. Speed, temperature, and entropy would then all result from the little bang.
  5. BillO

    BillO Well-Known Member

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    Ooooh, great question!

    My first reply would be, what laws of physics?

    Ours? Need not apply... different universe here…

    I’d go as far as to say that the basic metrics of our physics would not apply. What meaning would mass, length and time have in this universe?

    Back in my day this would have been a four or five pint question....
  6. beenthere

    beenthere AAC Fanatic!

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    The laws do not apply during: Star Trek, any George Lucas movie, any Matrix movie.

    Actually, the presence of a molecule is more interesting. Molecules are composed of two or more dissimilar atoms, so the question of the origin of those atoms and the means by which they made a chemical bond sort of implies some off-stage energy. Energy would show up as momentum, but how do you express if without a metric?

    Mass in that case is something like the tree falling in the forest - without another mass for gravitational attraction, does mass exist?

    Several pitchers, at least.
  7. Dave

    Dave Senior Member Staff Member

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    I would say temperature, speed and entorpy are relative concepts - in a universe with a single isolated molecule these concepts have no meaning (how far is A from B if one doesn't exist?). Only when we have multiple molecules do they take on meaning as the basis of laws of physics.

    Dave
  8. leftyretro

    leftyretro Active Member

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    Seemed to me a few such laws are either broken or bent often at
    Callahan's Place.

    Lefty
  9. studiot

    studiot Thread Starter E-book Developer

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    I would beg to differ here.

    Molecules are the smallest indivisible unit of any substance of fixed stochiometric composition, i.e.obeying the Law of Fixed Proportions.

    As such the smallest unit of gasses such as Helium is a single atom.

    Not all single atoms are molecules and not all molecules are single atoms, but sometimes they are one and the same thing.

    I'm glad you mentioned this because there are many eminent physicists who hold that the laws of Physics were different around the time of our 'Big Bang'

    As regards which physical laws or processes which might apply to my theoretical universe, consider

    I am assuming our molecule/atom is conventionally constructed of elementary particles and internally subject to the same laws that govern its internal mechanics as molecules in our own universe.

    If we consider an energy probability function for our molecule we should be able to assign a probability for any given energy and the integral over the entire line should sum to unity.

    Molecules in our universe emit radiation, due to their position on a similar energy probability scale, and some exhibit thermionic emission. So presumably the isolated molecule would do the same at appropriate energy states.

    These properties can also be related to a temperature scale.

    In principle we could thus also communicate by 'radio' with this molecule.
  10. Bill_Marsden

    Bill_Marsden Moderator Staff Member

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    How about black holes? The laws are definately different inside an event horizen.

    I don't know how the singularity would be defined, but it is a particle, of a sort.
  11. b.shahvir

    b.shahvir Active Member

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    Dear Studiot,

    I would have to go with Dave when he says that the laws of Physics would be applicable if you are talking about multiple molecules which form ‘matter’. I think the Laws of Physics would not apply to the Universe as a whole to the extent it would apply on Earth!

    Any matter possesses finite amount of mass.
    The major constituant of any universe (theoretical or practical) is ‘Space’ which itself is infinite and hence unfathomable. Infinite space in turn is the substratum of finite matter (multiple molecules). It is on this finite matter that the Laws of Physics are applicable in its entirety!

    It is not necessary that Quantum Mechanics or Physics is applicable everywhere in our Universe! There are many areas or ‘pockets’ in this infinite universe which contradict the principles of Physics. Take Black Holes for instant. The gravitational pull due to the Black Hole is so phenomenal (theoretically infinite), that it distorts (bends) the path of light as the speed of light is modified when it approaches it (it would also distort the ‘communication by radiation’ between your molecules, as mentioned by you). This itself is an exception to the laws of Physics, per se, which are applicable to our planet or to any matter in our universe.

    I think the same logic would also apply in your case on molecules (multiple molecules being considered) as it would also affect the entropy, speed or temperature of the molecules which are held together by atomic forces in the substratum of infinite space. There may be many parallel universes beyond the Black Holes, then the question is, would the Laws of Physics, applicable to the matter in our universe, are applicable to the matter in these parallel universes as well? Going by the variations or exceptions in the Laws of Quantum Mechanics and Physics in our own Universe, I would beg to differ!

    A single atom (eg Helium) still consists of multiple particles (electrons, protons, neutrons,neutrinos, quarks…etc and hence exceptions pertaining to the Laws of Quantum Mechanics and Physics are also applicable to it as well.
    I still strongly feel single molecules have no meaning until they come together to form matter, on which the Laws of Quantum Mechanics or Physics are then applicable albeit with certain exceptions when we consider the Universe as a whole as stated above.

    P.S. When you are free from your pre-occupation with the laws of Physics affecting your universe, please do divert your attention and reply to my Electrical threads which are of utmost importance to me in my universe. This is a humble request, absolutely no offense intended! :D

    Kind Regards,
    Shahvir
  12. KL7AJ

    KL7AJ E-book Developer

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    I would beg to differ that the laws of physics are different inside a black hole. Certainly they are outside our normal experience...but the laws of physics as we know them PREDICT fairly precisely what would happen inside the black hole.

    I think it's safest to say some laws are MORE RELEVANT under certain conditions...but the fact that a black hole has a recognizeable behavior tells us it not only follows law..but law that we KNOW a great deal about!

    eric
  13. beenthere

    beenthere AAC Fanatic!

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    The single molecule puts me in mind of Fred Hoyle, and continuous creation. But I suppose that only enough particles could come to exist, and somehow assemble into atoms, and thence into that molecule.

    I would also suppose that the molecule would warp spacetime, so gravity would exist, even if it would be largely irrelevant, given an absence of any other entity. Time would have meaning, as there would have been a duration between the formation of particles and the assembly of the molecule. Would it have meaning after that assembly, any more than gravity.

    How about energy? Does the local warp in spacetime provide a metric to measure momentum? How can we say that the single warp has displaced over time? Measuring from a point to that same point yields 0.
  14. stellarpower

    stellarpower Member

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    In a slightly abstract way, linking back to the original question, the laws of physics always apply. It's just that different rules apply in different circumstances. Similarly, one can never disprove the laws of physics. The laws don't change, we just have to correct our understanding of them, 'coz we messed up'. Also, due to quantum mechanics, as far as I know, your molecule can't exist, as it needs an observer to collapse the wave function. Technically, it shouldn't be a molecule, it should just be probability, and as there hasn't been an observer yet, it should have infinite possibility as it's state hasn't been restricted. On the other hand, I might be completely wrong, as I haven't finished my book on quantum physics yet!

    I hope this helps.
  15. studiot

    studiot Thread Starter E-book Developer

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    I notice that both the current Scientific American and New Scientist have leads about situations in astronomy where the laws of Physics are allegedly violated.
  16. Bill_Marsden

    Bill_Marsden Moderator Staff Member

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    Really, Infinite density?

    Possibly infinite space? That hole is deep, very deep.

    Time Travel in any direction?

    On this subject we don't really know too much, we look for signatures we think mark them, but that is the outside, where our laws apply. The inside we make a lot of assumptions, mostly untested and non-verifiable.

    Then there is the little issue of rotating black holes, which in theory can form a gateway to ???.

    Multiple event horizons are also possible.

    My own suspicion is the boundary layer is a dividing wall between universes, but that isn't provable either.

    We can't even prove Hawking Radiation exists, though I tend to favor the theory.
  17. studiot

    studiot Thread Starter E-book Developer

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    SCIAM and NS are not talking about black holes, although the articles do compare their proposals with them.

    Older readers of these sagas may remember previous incarnations of astrophysical 'theories of everything' that explained all (well most) - ( well some anyway)
    of the currently known and observed phenomenon. Yes the names of Hoyle and Bondi spring to mind.

    After the honeymoon period, doubts and exceptions started to creep in. This was followed by new observations, new phenomena and new theories. Theories 'cause that's all they are.

    I think we are just over the honeymoon period with black holes and a new darling is showing a leg. She is called the 'Naked Singularity' by SCIAM.
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