What's Space?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Goldtop, Aug 3, 2018.

  1. Goldtop Registered Senior Member

    Here's what I know about space, so please school me where my logic goes wrong.

    Space is the distance between two objects, but it also acts as the medium to which all other forms of mass and energy propagate throughout the universe. Electromagnetic radiation, for example can travel through it but hits a wall at c, something to do with the permittivity and mermiability of space. This tells me space is made of something, but it's unknown if that something is quantized or not.

    As far as I can tell, the Big Bang event was little more than the introduction of space between every single Planck length material all at the same time. The material being what form mass and energy were prior to it.

    To me, this says space shouldn't be quantized, that the space between galaxies is the same as between atoms. Space would not then be a "foam" since a foam would have to keep multiplying it's little bubbles. A non-quantized space could be any size. The speed of light wouldn't be a constant in an ever expanding see of foam, but would if space wasn't quantized.

    This now makes me jump to the irrational assertion that it is space which causes gravity. Without space, there would be no need for gravity.

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  3. James R Just this guy, you know? Staff Member

    Hello Goldtop:

    Electromagnetic waves travel at the speed of light in vacuum. They do not speed up or slow down. Nobody actually knows why the speed of light is finite. It's just a fact of our universe.

    Space isn't made of something. Space contains things - fields, the odd particle here and there.

    Talking about what was "prior" to the Big Bang is difficult, due to the fact that the Big Bang is a singularity in time in our best current cosmological theory (general relativity). Nobody knows what, if anything, was "prior" to the Big Bang. (Also, in a sense, the Big Bang is still going on today.)

    I don't know how you can derive any conclusions about quantisation from what you've written.

    If space is empty, though, why would you expect the space between galaxies to be any different from the space between atoms? Galaxies are just bunches of atoms, after all.

    You need to specify more precisely what you mean when you say spacetime is a "foam". It's all rather vague.

    Why? What has size got to do with quantisation?

    Why not? Explain.

    In general relativity, gravity is the curvature of spacetime. That curvature is caused by mass and energy.

    Without space, there'd be nothing.
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  5. Seattle Valued Senior Member

    I have a theory that there is no light. Light is only the absence of dark. I have a theory of dark.
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  7. socratus Registered Member

    There are two kinds of ''space''
    a) space and time (Descartes coordinates + time)
    b) space-time (Minkowski 4=D or cone-space )
  8. Goldtop Registered Senior Member

    Hello James:

    I was under the impression that the permitivity and permeability of space had something to do with the finite speed of light? Would this not precipitate that space was made of something?

    Yes, I would assume all the matter in the universe was a one time all together in that there was no space prior to the Big Bang. A singularity could then describe such a phenomenon, but for the most part, do we know if that singularity was a singularity due to gravity or because there was no space?

    I thought that with an incomplete theory of gravity, it was assumed that space didn't have to be fundamentally "smooth" but instead consist of very small regions that fluctuate like in a "foam" like manner? I was arguing that space does indeed need to be 'smooth' in order for the speed of light to be constant. If space fluctuated like a foam, electromagnetic radiation could also fluctuate going through it, that is, if permittivity and permeability has something to do with space.

    It almost seems like we need 3 different theories for gravity, one for quantum, General Relativity and another for large scale objects like galaxies? I suspect space being or not being quantized would have something to do with it, in that the medium of space should be smooth.

    A smooth space would allow smooth transition of electromagnetic radiation while a constantly ever changing foam would not, hence the constant speed of light.

    Could it be such that the very existence of space is the cause of gravity, which causes mass and energy to curve it?

    But, wouldn't all the mass and energy in the universe still exist?

    Thanks for the responses, btw.
  9. exchemist Valued Senior Member

    You raise an interesting point with your comments on permeability and permittivity. Space appears to have properties, which suggests it is not a mere absence of anything. QFT also suggests it has certain behaviour, consistent with the presence of so-called vacuum fluctuations.

    I suppose it is a nice point to debate what we mean by nothing............
  10. Write4U Valued Senior Member

    I have always preferred to phrase it this way; Space is a permittive condition which allows EM waves to travel, but no faster than the speed of light, because that is the fastest possible speed which space allows for explication of something from an implicate state to a state of reality. QM.
  11. keith prosser Registered Member

    It seems to me that you want to resurrect 'ether'! You also mix it with the Higgs field which is the source of mass and, hence, gravity. How I wish I understood any of this stuff, but my fascination is greater than my knowledge!
  12. Seattle Valued Senior Member

    The strong force is the source of most of the gravity that we observe. Probably 2% comes from the Higgs field.
  13. NotEinstein Valued Senior Member

    What do you mean by that? Both gravity and the strong force are completely different fundamental forces.

    Source please.
  14. NotEinstein Valued Senior Member

    Please give the definition of "condition" you are using. It seems that you are suggesting that space is a purely abstract concept.
  15. Write4U Valued Senior Member

    Not really, it's a simple and straight forward generic definition.

    condition, noun,

    1. the state of something, especially with regard to its appearance, quality, or working order.
    "the wiring is in good condition"
    synonyms: state, shape, order


    2. something essential to the appearance or occurrence of something else : prerequisite:
    such as
    a : an environmental requirement
    • Available oxygen is an essential condition for animal life.

    3. A situation that must exist before something else is possible or permitted.


    4. a restricting, limiting, or modifying circumstance: It can happen only under certain conditions
    1. a circumstance indispensable to some result; prerequisite; that on which something else is contingent: conditions of acceptance.
    2. Usually conditions. Existing circumstances:

    As far as the ability to become reality being restricted by the speed of light is IMO proven during the "inflationary epoch" which occurred at FTL. But of course space did not yet exist, as it was being created during that very short time.

    Before then there was only a "permittive condition" without any physical restricions.
    Space is a permittive condition, but which poses certain restrictions on its permissions.

    This may seem vague and undefined, but I am trying to establish a reasonable foundation from which other fundamental properties may be gleaned in a hierarchical ordering of the permissions and restrictions in the ordering pattern we call spacetime.
    Last edited: Aug 4, 2018
  16. NotEinstein Valued Senior Member

    1) "space" is the "state of something";
    2) "space" is essential to "something else";
    3) "space" is a "situation";
    4) "space" is a "circumstance".

    Taking all these together, it suggests that I was right even though you just answered "not really". Do you consider space to be more than merely a "permittive condition" (which we now know to be a just a "condition", due to your definition 3)?
  17. Seattle Valued Senior Member

    Yes, they are both one of the 4 fundamental forces. The reference was to the Higgs field. It does contribute to mass but it's not what gives most of the mass to what we observe around us.

    That comes from the strong force binding the kinetic energy in the nucleus of an atom. That energy (remember E=MC2) is where most of our observable mass comes from and not from the Higgs. That's just because that bound energy in an atom is much more than the mass provided by the Higgs field.

    As far as a link or a source...you can find one easily enough. This is not something controversial that is only found on wacko sites. Pick any mainstream source of your choosing.
    Last edited: Aug 4, 2018
  18. NotEinstein Valued Senior Member

    Ah, OK, I thought you were suggesting the strong force directly contributes to the gravitational force, but you meant that the strong interaction contributes to the energy, thus to spacetime curvature, which is gravity. Got it.

    Can you please still point me to a source for your claim that most of the contributions to gravity come from the strong interaction, while 2% probably comes from the Higgs field?
  19. Seattle Valued Senior Member

    I'm talking about mass. You are talking about gravity. It's semantics but just to be clear...
  20. keith prosser Registered Member

  21. NotEinstein Valued Senior Member

    No, you were talking about gravity:
    And what about that source?
  22. Seattle Valued Senior Member

    Anything other than this was a typo. I was (and am) talking about mass.
  23. NotEinstein Valued Senior Member

    Your video says 21 grams is caused by the Higgs mechanism, and Seattle says that's about 2%. Are you claiming the average person weighs about 1 kilogram?

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