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B Expanding space time and Virtual particles

  1. Dec 9, 2017 #1
    If space time (the universe) is infinitely expanding what happens when it rips? Have we observed Virtual particles in an area and counted them? Does the expansion of space time affect the amount of Virtual particles in a particular area? Is it theoretically possible to expand space time to a point that it would rip? Is it possible that the higgs field expands with space time? Could the gravity from 1 single virtual particle be enough to cause a rip in a enormously empty space time void from infinite (maybe not) expansion?
  2. jcsd
  3. Dec 9, 2017 #2


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    It doesn't rip. Spacetime is not a fabric or anything else that can rip. Even the "big rip" in cosmology is nothing like what happens when you rip a hole in a piece of cloth.

    No, they are, by definition, unobservable.You cannot ever count them. Not even a single one.

    The number of virtual particles within a region of space is indeterminate as far as I know. Since they aren't observable, I don't think you can even talk about how many there are.

    Expansion is geometrical property which is associated with theories involving geometry (like General Relativity) or the motion of objects within space. The Higgs field is not one of these and trying to say whether it expands or not is... problematic.
  4. Dec 9, 2017 #3


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    You are asking a lot of very touchy questions in physics in one thread. The question you have asked is a question which several people have tried to answer several times and there are quite a few ideas.

    Let me look at your first question, is space infinitely expanding? Spacetime is not going to rip and rupture at a certain point like you may be inclined to believe. The misnomer that spacetime can rip is generated when people used the rubber membrane analogy for the effects of mass on spacetime. Spacetime is infinitely smooth and can be stretched forever and forever without "ripping". This is what Einstein believed. Spacetime can infinitely stretch and never rip.

    However, many physicists believed other "sub-theories" which were an extension of spacetime. String theorists who are believers of rolled up dimensions (read about String Theory) believe that spacetime curves around and around like a circle. If you were to navigate in one direction, you would reach back where you are in space. Then there are believers that think spacetime can actually rip when there is a large enough mass (this is the theory of wormholes).

    All of these theories are quite difficult to understand and even more difficult to quantify. No one has confirmed any theory for sure because we have no means of confirming anything.

    As for your interest in virtual particles. Virtual particles are not particles. They are small ripples in spacetime. Take a look at this link which explains it very well: https://profmattstrassler.com/artic...ysics-basics/virtual-particles-what-are-they/
  5. Dec 9, 2017 #4
    rip is a bad analogy. will space become "less dense" (or more fragile) the more it expands? it is not able to retain the same properties depending on the amount of matter occupying it so why isn't a tear or rip theoretically possible? (im bad at maths).

    this answer bewilders me (more maths) If they are there there must be a way to observe them even if we distort the outcome (double slit) at least we would know they actually exist.

    there must be a way (see last response ;) )

    "Problimatic" how so? fields are the very base of the universe. fields are able to be manipulated. the higgs is no different...
  6. Dec 9, 2017 #5
    thank you... i will read it and reply...
  7. Dec 9, 2017 #6


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    There is no quantifiable state where space will become fragile. Sure, you can try and think of it becoming fragile, but that analogy is useless since it is never going to rip. There is just no way for it to ever rip or be fragile. It is also not going to become less dense, it is just stretching and there are some mathematical and physical effects of this happening. Spacetime is NOT a piece of squishy stretchy rubber. It is a dimension.

    BTW, if you ever want to fully understand spacetime, I'm afraid you might hit some math.
  8. Dec 9, 2017 #7


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    A number of off-topic posts have been removed. Please remember the Physics Forums rule about not posting personal theories and speculation outside of mainstream science.
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