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Is dimensionless singularity truly dimensionless?

  1. Mar 29, 2014 #1
    Hi, everybody.
    I have the question about initial, gravitational big bang singularity.
    My first question is if the universe was created from dimensionless singularity, is singularity truly dimensionless?
    Can extreme gravity truly destroy all that is (space, time, matter, energy, just about everything you can or you can't think of at an given moment) and come back to dimensionless singularity.

    I wonder if physicists consider that singularity truly exists, since all the equations break down in it?
    I read Marcus posts on these subjects, but I'm still not sure what to think?

    Should I, and do you actually think that singularity is something real, I mean how can it be real if it literally destroy physics and space-time.
    I had a chat with someone who actually says that as a proven fact, so I came here without knowing what to think?

    Should I consider singularity as a fact?
    Should I consider that dimensionless-ness/sizelessness does exist?
    Is dimensionless-ness/sizelessness a proven fact, I'm not talking about just singularity, I'm also talking about dimensionless/size-less particles?

    I mean, is there any way to experimentally prove dimensionless singularity and dimensionless particles?
    How do you do it, what are the methods?

    There is also one more thing that tortures me:
    If universe does not expand into anything/nothing at all, I have a hypothetical question:

    Let's suppose you have to separate universes, both they have been created from dimensionless singularity, so let's suppose scientists want to get into another universe, how exactly can they do it, since there is absolutely nothing outside of any of those 2 universes?

    I heard this from any documentary if human civilization could reach such level of science and technology with so much energy in which you can open portal to another universe?
    But my question here is: how can you open portal at all to anything at all if there is absolutely nothing (no space, no time not anything, complete non-existence) between these 2 universes???

    Basically, what this is implying is that both universe and dimensionless singularity were created from absolutely nothing/non-existence, so non-existence creates existence?
    Of course that science cannot tell what was before the big bang and before singularity, but we have to think for just one minute, where did singularity came from as well.

    Also, dimensionless particles like let's say photon, how can they exist if they are truly dimensionless, how can they have effects on sorrounding environment and just about everything?

    But do physicists truly take singularity as literally dimensionless and literally the end of space-time, or do physicists take singularity and its dimensionlessness only as figurative speech, and yet the are aware that dimensionlessness does not exist-can anyone give me more detailed explanation here, because I truly don't know should I understand singularity and particles literally dimensionless or not, do the physicists understand singularity literally dimensionless of not?

    Does dimensionlessness of singularity and do dimensionless particles truly exist or not?

    How can the existence any of these non-existence and dimensionless singularity be experimentally and practically proven at all?
    That's all, I truly hope you can shed some light in this darkness.

    That' all.
    I also need to mention something, I owe apology to Drakkith for my pm-s to him regarding these subjects, regarding these questions.
    That was a bad and arrogant behaviour from me, I was lucky not to get banned permanently.
    Drakkith was ok to me all the time, and I truly don't know how did he have nerves at all, because I'd lose patience with myself too as well.

    Thank you for your time and patience.
    Last edited: Mar 29, 2014
  2. jcsd
  3. Mar 29, 2014 #2
    Some things that might help:

    Think about what causality actually is. Is there really any meaning to asking what caused the first event? By definition, nothing caused it. Our brains are prediction machines highly specialised to analyse cause and effect, so it's no suprise that they should get frustrated when they're asked to contemplate the one thing that doesn't fit what they were designed to do.

    Not all cosmologists believe that there is nothing outside our universe and not all believe that time and space originated at a singularity at the beginning of it.

    Hawking changes his mind quite a lot, but talks of the singularity occuring in imaginary time. I doubt that many cosmolgists really know what he's talking about.

    We have data for measurements incredibly close to what we call the start of our universe but no way of seeing before that.

    I'm not sure that it helps with your frustration with the subject but there are different ways of looking at the problem and some things that you can look into.
    Last edited: Mar 29, 2014
  4. Mar 29, 2014 #3


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    Many physicists, and laymen, struggle with the concept of a universe from 'nothing' - which probably accounts for the popularity of multiverse and religious ideologies. I fail to see how either alternative is satisfactory.
    Last edited: Mar 29, 2014
  5. Mar 29, 2014 #4


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    To my understanding, no, most scientists who actually work on this issue don't believe the singularity is real.

    I wouldn't. I'd consider it to be the point where our theories and models break down and stop giving reliable predictions.

    This is a complicated issue that cannot be answered in just a few sentences. Elementary particles are considered to be "point-like", but this does not mean that they are truly dimensionless objects. The reality is that the concept of size isn't very meaningful at the quantum level for fundamental particles.

    We can't start with the premise that there are two universes but nothing "outside" either of them. Furthermore, there is no known way to get from any universe to another in most of the various multiverse theories.

    Whatever you heard it from most certainly wasn't using mainstream science to come up with these conclusions, so we can't answer this. Portals allowing travel to places either inside or outside our universe don't exist as far as we know.

    Real science does not imply that. It makes certain predictions using theories and models that have very real limitations. Attempting to extrapolate beyond these models is almost guaranteed to either be wrong or not make any sense. So while the Big Bang Theory and the Standard Model of Cosmology allow us to make predictions very far back in time, they are ultimately limited in their scope to after the universe already existed.

    Unfortunately, most of your questions are on topics that science simply doesn't have a good answer for yet. Where did the universe come from? How small can things ultimately get? What is the size of the universe? None of these have satisfactory answers yet (And they may never have satisfactory answers).
  6. Mar 30, 2014 #5
    To be honest, that kind of surprised me, because I thought all cosmologists think there is absolutely nothing outside the universe and that space and time originated in singularity.
  7. Mar 30, 2014 #6
    Could you be more specific?
    What do you mean by probably accounts for the popularity of the universe?
    I guess, you mean multiverse theories are fairy tales or something like that?
  8. Mar 30, 2014 #7
    OK, this changes everything what I thought about singularity.

    OK, what do you mean by "the reality is that the concept of size isn't very meaningful at the quantum level for fundamental particles"? Does it have to do with Heisenberg's uncertainty principle or something else?

    What about dimensionless particles should we consider these particles (like photon and electron) truly dimensionless or they are just very, very small?
    If you look at this list of dimensionless quantities-should we consider this as fact as well?

    Just for the record, it was Michio Kaku who was saying this as an possibility if we could somehow achieve that kind of scientific and technological level to achieve what I wrote above.


    Sadly, but true.

    True, sadly, but true, my only hope science and technology will one day achieve level where we could actually detect beyond from what we can see now with telescopes, microscopes and that we can see further and that we can see smaller than today.
    Last edited: Mar 30, 2014
  9. Mar 30, 2014 #8
    Kaku will be referring to the open questions of whether such a thing can exist as a traversable wormhole formed by an Einstein Rosen bridge at the centre of a rotating black hole and if they can exist, where (and when) they lead. He tries very hard to engage non-physicists in physics and picks the most fantastical things to talk about.

    I can't vouch for the book, but if you want to find out more you could try this:

    The Physics of Stargates: Parallel Universes, Time Travel, and the Enigma of Wormhole Physics by Enrico Rodrigo

    The author has researched the subject professionally and published papers on it.
    Last edited: Mar 30, 2014
  10. Mar 30, 2014 #9
    OK, and could you also give (as well as others, too) opinion on question I asked Drakkith:
    OK, what do you mean by "the reality is that the concept of size isn't very meaningful at the quantum level for fundamental particles"? Does it have to do with Heisenberg's uncertainty principle or something else?

    What about dimensionless particles should we consider these particles (like photon and electron) truly dimensionless or they are just very, very small?
    Big thanks.
  11. Mar 30, 2014 #10
    I know Drakkith's answer seems vague, but I'm not sure that we have a better one at the moment. An elementary particle is only ever measured at an exact position and the concept of the existence of a particle beyond a measurement event is a complex one. When we do consider a particle to exist beyond a measurement event, its position isn't considered perfectly localised, which is related to the HUP. In the newer theories, which remain unproven, there's growing interest in the concept of the Planck length, which again is related to the HUP. For instance, in superstring theory, a string is of the Planck length, but I'm not sure that we could unambiguously say the size of a particle is the length of its string.
    Last edited: Mar 30, 2014
  12. Mar 30, 2014 #11


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  13. Apr 1, 2014 #12
    I actually though that is scientifically proven that dimensionless particles do exist-but like I asked before how do you prove that something is dimensionless with scientific experiments?
  14. Apr 1, 2014 #13
    That's certainly not true. String theory requires that particles exist in 10 dimensions. Other theories use the concept of a point particle, but that can be a misleading term for the reasons already given in this thread.
    Last edited: Apr 1, 2014
  15. Apr 1, 2014 #14
    So photon, quark, electron, boson and etc. are not dimensionless particles?
    Because when you google it, you'll find that these particles are actually dimensionless.
  16. Apr 1, 2014 #15
    You'll have to provide a more specific reference than google.
  17. Apr 1, 2014 #16
    Well, I don't know how good or bad is wikipedia, but I also have been reading in so many books, TV documentaries, Scientific American that photon, electron (which are elementary particles) are both dimensionless, I truly don't know if it has ever been posted from arxiv.org or anything like it.

    Unfortunately I don't have any kind of link, but try to google it and you'll find that particles like electrons and photons are considered dimensionless.
  18. Apr 1, 2014 #17
    Wikipedia's usually very good. Search for "point particle" there. That should explain what we're trying to get across very well.

    Let me offer a comparison based upon scale:

    When we measure the position of an electron we get a single location
    The position of an electron gets 'spread' across an entire atom at the scale of ~ 10^-10 m
    In superstring theory an electron has a string of length ~ 10^-35 m
    The entire observable universe is ~ 10^26 m
    (You might want to check these numbers).

    To give an idea of scale, if a string were the size of an atom, then a human would be the size of the universe.

    Which would you say is an electron size? The spread around an atom? The size of a string? The point that it's measured at? I'd say all three are valid and that's why we say that the concept of size of an elementary particle doesn't have much meaning.
    Last edited: Apr 1, 2014
  19. Apr 1, 2014 #18


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    We don't have a good answer for you. We can only say that they are point-like as far as we know, depending on how you define size for an elementary particle.
  20. Apr 1, 2014 #19
    To add a side note, particle physics can determine a particles mass, spin and momentum. However much of the information we get on a particle is usually measured by its deflections and impacts.
    Much of the particles were discovered by shooting particles at a small region and watching for path interference patterns. Most detection mechanisms rely on the fact that when high-energy charged particles pass through matter they ionize atoms along their path.

    The "Wilson cloud chamber" is an early example of a particle detector.
  21. Apr 2, 2014 #20
    When we talk about dimensionlessnes of particles; is the following true?
    According to one professor of physics:
    Yes, experiments with these particles have not shown any internal structure, deserving the name elementary particle. Why does that mean they are point particles? Relativity forbids faster than light propagation of signals. So pushing on one side of an extended electron would instantaneously move the other side (any elasticity would mean internal structure). That cannot be the case unless the size is zero.

    But how does this exactly prove that electron is dimensionless?
  22. Apr 2, 2014 #21
    But how does this prove that electron, quark, or photon and etc. are all dimensionless particles?
    They even say that composite particles are also dimensionless?
  23. Apr 2, 2014 #22
    Ok, understood, but if that's the case why is everyone talking about electron as purely dimensionless particle, when based on your post it is not dimensionless at all, after all?
  24. Apr 2, 2014 #23
    ... In QM. As far as they know. We can't be sure or able to tell the internal structure of a particle-absolute size. In a sense that we can deduce any inferences from the supposition that it is localized, at the cost of momentum uncertainty. Meaning particle is a wave packet - in principle have any given size and shape(above).
  25. Apr 2, 2014 #24
    That really needs a reference. If I search the internet for that quote, I find one result and it's on a Croation religion forum.

    Is that where you got it from?
    Last edited: Apr 2, 2014
  26. Apr 2, 2014 #25


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    I don't think you understood his post at all. Look again.

    He's saying that the size of an elementary particle such as an electron will be different depending on what you accept as size.

    To quote a paper on arxiv: http://arxiv.org/abs/quant-ph/0702112

    In other words, the electron behaves either as a point-like charge or as an extended distribution depending on how you ask the question. (Much like how a particle can be viewed as either a particle or a wave depending on how you set up the experiment)

    You keep wanting "proof" that an elementary particle is zero-dimensional. Perhaps it is best to say that an elementary particle can be either non-dimensional or 3-dimensional depending on how you look at it. There are times when the point particle concept is very useful and times when the "smeared out" 3-d view is useful.

    If you take anything away from this thread I think the above description would be most useful.
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