Length Contraction in the Muon Experiment

Discussion in 'Physics & Math' started by Aer, Jul 26, 2005.

  1. Aer Registered Senior Member

    Messages:
    2,250
    OK - so you think "dark accelerator" = "dark matter" and you have evidence for "dark accelerertors".

    I don't think dark accelerators are dark matter. The accelerators, whatever they are, are emitting gamma-rays. Dark matter does not emit any detectable radiation.

    Your link doesn't come to the conclusion you came to. So I am assuming you made it up. That is your prerogative, do you have creditials to make such an analysis?
     
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  3. James R Just this guy, you know? Staff Member

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    Aer:

    The "inside" has no edge. Our universe seems to be spatially infinite. So, nothing prevents you travelling "outwards", but you can never get outside the universe.

    As I said before, the universe, as far as we can tell, is homogenous on large scales. There is not a central mass-filled region surrounded by nothingness. The mass is everywhere. Moving "outwards", you never get away from the "mass filled universe".

    I agree.
     
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  5. Aer Registered Senior Member

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    Seems infinite according to who? We can't see anything past a specified distance I thought (is this incorrect?). I thought that defined the age of the universe and the big bang concept meant that all matter/energy originated at one point and has radiated outward ever since. If it is continuing to radiate outward, then this space that it is radiating out to would be the area of mass deficiency I was refering to.


    I didn't mean that you would be able to get away from it. But you can "imagine" something else to be out there. Anyway - I think this point has gone off the main topic.
     
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  7. James R Just this guy, you know? Staff Member

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    Aer:

    According to observations of the average energy density of the universe, combined with GR cosmological models.

    No, that's right. But we only see a part of the complete universe - the part that light has had time to reach us from.

    No. The big bang happened everywhere at once. The big bang was an explosion of spacetime, which is very different to an explosion in spacetime.

    The matter didn't start at one point and expand outwards into pre-existing space. The space and matter both came into existence at the same point, and everything expanded.

    Think of the universe as a loaf of raisin bread baking in the oven. The raisins are galaxies. As the loaf bakes, the raisins all move further apart from each other, but there is no part of the loaf without any raisins, at any time.
     
  8. Aer Registered Senior Member

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    So I was right before when I simplified the model of the universe to neglect acceleration.

    Is this the only view? I have heard this but wasn't sure if that was correct or not. With this point of view, is it logical to think of "other" universes?
     
  9. James R Just this guy, you know? Staff Member

    Messages:
    30,379
    I don't recall that part of the conversation, which I think you were having with somebody else, so I can't really comment.

    It's the only view in accordance with the standard big bang model. If you want to use some kind of alternate idea, then it's not the only view.

    It is only logical to picture "other universes" as completely causally disconnected from our universe, as I said before. The idea of multiple "bubble universes" seems to be a popular one among certain string theorists. I'm not sure why. There is, of course, no evidence of "other universes", and I personally doubt there ever can be, so I question the usefulness of the idea. Of course, that doesn't mean it's wrong - just unverifiable.
     
  10. 2inquisitive The Devil is in the details Registered Senior Member

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    3,181
    Again, you are distorting what I said, Aer. Can you not comprehend English, or
    is it common for you to construct strawmen, attribute them to your opposition
    so you can 'shoot them down'? I found an earlier article I read before the 'dark accelerator' paper was published. It is from the CERN Courier. When
    the 'dark accelerator' paper was published, I remembered the earlier dark matter/gamma ray connection. I did not 'make it up'. The ignorance is yours,
    not mine. An excerpt and link:

    "In HESS data taken towards the centre of our galaxy (figure 2), a strong gamma-ray source stands out, coincident with Sagittarius A*, the supermassive black hole at the galactic core (Aharonian et al. 2004b). HESS can locate the source of the VHE radiation to within 30 arcseconds from the Galactic Centre, an order-of-magnitude improvement in precision compared with other instruments. The Galactic Centre has long been predicted as a source of VHE gamma rays generated in the accumulation and annihilation of dark-matter particles, for example the lightest stable supersymmetric particles. The characteristics of the gamma-ray signal detected by HESS are indeed consistent with the expected features for dark-matter annihilation, but would require very heavy (> 10 TeV) dark-matter particles and a large annihilation rate or enhanced density of the dark matter at the Galactic Centre. More conventional explanations include particle acceleration in the 10,000-year-old supernova remnant Sagittarius A East, which is still consistent with the HESS error circle for the source location. Future data should pin down the source location even better. Another key question is whether the gamma-ray flux is constant, or whether it varies, pointing to an origin near the Schwarzschild radius of the central black hole."
    http://www.cerncourier.com/main/article/45/1/22

    Now, a copy of what I actually posted earlier. I did not state 'dark accelerators=dark matter. You had asked for my explaination of how dark matter explains dark accelerators. Notice I stated 'speculation' involving two
    scenarios.


    "I'm afraid I can't answer your question. As far as I know, no one knows what
    'dark accelerators' actually are. All I have read at this point is that massive
    amounts of VERY high energy gamma rays are being emitted from areas of space where NOTHING is detected to exist. Only the gamma rays themselves
    are detected. If you are asking for 'speculation', possibly a convential black hole may be feeding on dark matter, which would not detectable in the accretion disk. Does collisions of dark matter particles in the accretion disk produce gamma ray particles? I don't know. Or more 'speculation' may be that
    the source is something like a black hole, except the black hole itself is composed of dark matter. Again, I don't think anyone knows yet, this is new
    physics. It came as a surprise, and convential physics has no theory to explain what may be happening."

    As I said, DO NOT FUCKING DISTORT WHAT I POST.
     
    Last edited: Aug 17, 2005
  11. Aer Registered Senior Member

    Messages:
    2,250
    Let's take a look what has been distorted.

    So, from the red portion, we have you claiming that dark matter is undeniable.

    undeniable: plainly true, INCONTESTABLE

    Did you mean to say undeniable? You can change now if you want, but undeniable to me requires hard proof.

    You give one link to prove your point, so SORRY IF I ASSUMED THIS WAS YOUR HARD PROOF. Because it is obvious to anyone who reads the link you provided, that that is not hard proof of dark matter - so much so that you accused me of DISTORTING WHAT YOU SAID when I told you that was not hard proof of dark matter.

    I think I just explained everything above quite nicely. There was no malicious intent on my part and if you are capable of comprehending English with any success, I think you should be able to agree that this is true.



    Now you are including new information from different articles to support your position. Why didn't you just provide this article to begin with?


    And if you had provided that last article to begin with, I could have pointed out to you, just as you have admitted yourself that the explaination involved SPECULATION OF THE EXISTENCE OF DARK MATTER. Again, I was right - SPECULATION does not make something UNDENIABLE because UNDENIABLE requires HARD PROOF.


    And one last thing. I believe Stephen Hawking's latest theory flip on black holes makes it possible for black holes to leak radiation - this is all without any dark matter.

    link
     
  12. 2inquisitive The Devil is in the details Registered Senior Member

    Messages:
    3,181
    by Aer:


    "Let's take a look what has been distorted."
    ================================================================

    You know perfectly well what you have distorted. I have exposed part of it already.
    ----------------------------------------------------------------------------------

    by Aer:

    "So, from the red portion, we have you claiming that dark matter is undeniable."
    ==============================================================

    It is not only myself that believes the evidence for dark matter makes its existance
    undeniable, it also includes most of the physicists, astronomers and cosmologists in
    advanced science. You do not belong to that group, do you? Of course you don't, your
    knowledge is very limited regarding newer discoveries. Here is a link to just ONE SITE
    with some of the evidence. Notice I said evidence, not speculation. The speculation was to the mechanics of the dark accelerators, not dark matter itself.
    --------------------------------------------------------------------------------

    by Aer:

    "Now you are including new information from different articles to support your position. Why didn't you just provide this article to begin with?"
    ----------------------------------------------------------------------------------

    After being accused of 'making it up' by you, I went back and found one of the articles I had read a few months ago. As I stated, I remembered the general content
    of the article, but not WHERE the information was located or the link itself. Are you suggesting I can't introduce evidence to support my position because it makes you look uninformed?
    -------------------------------------------------------------------------------

    by Aer:

    "...just as you have admitted yourself that the explaination involved SPECULATION OF THE EXISTENCE OF DARK MATTER. "
    ============================================================

    Again, you fail to comprehend what was written. The speculation was with regards to the mechanics of dark accelerators, NOT THE EXISTENCE OF DARK MATTER. Here is just ONE link to help you gain a little knowledge concerning the evidence for dark matter. I also know more evidence, but it is not my job to educate you, only to support my position.
    http://www.physics.ucla.edu/hep/dm04/dm04agenda.htm
    --------------------------------------------------------------------------------

    by Aer:


    "And one last thing. I believe Stephen Hawking's latest theory flip on black holes makes it possible for black holes to leak radiation - this is all without any dark matter."
    ===============================================================

    So, you accept string theory without evidence and Dr. Hawking's hypothesis without
    evidence, but not real evidence for dark matter? Perhaps you could explain your 'scientific method' for me?
     
  13. Aer Registered Senior Member

    Messages:
    2,250
    I know not perfectly well ANYTHING that I have distorted!
    You said that dark matter is UNDENIABLE. Very well I say, so where is the PROOF? There is no proof you say - then you claim there is evidence as if that is somehow DIFFERENT from proof.

    evidence: stand as proof of

    This is insane! You cannot claim there is evidence of dark matter, only that dark matter is introduced to explain certain phenomenon. I am not denying the possibility that dark matter exists - I only pointed out that there is no proof that it exists. Just as there is no proof of length contraction or the relativity of simultaneity, there is no proof of dark matter. What is so hard to understand? Explainations that involve dark matter are not proof alone.



    But from the red section we have YOU saying "it seems to be undeniable to me" - not "most physicists say it is undeniable". OK - so now you say most every physicist/cosmologist/astronomer agree that dark matter is undeniable. Then why, I ask, do we have physicists still seeking proof of dark matter?

    Darkest Puzzle of the Cosmos With one team claiming success, physicists still seek proof of 'dark matter,' which is thought to comprise almost all of the material in the universe.






    I asked you once before and I'll ask you again. Do you have appropriate credentials to make any analysis in either physics or cosmology?


    That site contains a list of discussion topics/agendas concerning dark matter and dark energy. There is no evidence. If you had evidence, I suspect you would link directly to it. Instead you link to some dark accelerator article that doesn't even mention dark matter. Then you link to another dark accelerator article that tries to explain the phenomenon with dark matter, then you link to an agenda list concerning dark matter topics. Come on - this is really stupid. If you want to claim that I am ignorant of the evidence for dark matter - fine, but when I googled for this evidence, all I found were sites proclaiming physicists have no evidence that dark matter really exists and that they are search for ways to detect dark matter.

    I noticed. You should never have said evidence in the first place.

    The speculation was that dark matter was somehow involved with the dark accelerators.





    Holy crap - this is like talking to a retard.

    The speculation was that dark matter was somehow involved with the dark accelerators.




    Who said I accepted it? It is just as valid an explaination. The problem is, you think in order to entertain an explaination, you must accept it. There could be 3 or 4 equally acceptable explainations for the same phenomenon and they all could be incorrect. They are only unacceptable if there is anyway to rule them out (knowing the correct answer is the only way to rule out all other possibilities). I highly doubt we know everything there is to know about black holes/rest of the universe.
     
  14. 2inquisitive The Devil is in the details Registered Senior Member

    Messages:
    3,181
    by Aer:

    "This is insane! You cannot claim there is evidence of dark matter, only that dark matter is introduced to explain certain phenomenon. I am not denying the possibility that dark matter exists - I only pointed out that there is no proof that it exists."
    ================================================================

    Is there evidence that gravity exists, Aer? How do you know, what is it composed of,
    and how does it interact between two bodies? The same with dark matter, it is known
    to exist by the EFFECTS it produces. The 'search' for dark matter is to gain knowledge
    as to its composition. Here is a cut and paste from the article you linked written by
    Usha Lee McFarling of the esteemed science publication, the L.A. Times:

    "Searching for Dark Matter
    Dark matter makes up more than 90% of the universe but has never been detected using ordinary methods."

    I guess this is where you came to the conclusion that dark matter and dark energy were one and the same thing, before being corrected by James R.
    -----------------------------------------------------------------------------

    by Aer:

    "Holy crap - this is like talking to a retard.

    The speculation was that dark matter was somehow involved with the dark accelerators."
    ===============================================================

    Holy crap, this is like talking to a retard. MY speculation, which I made clear was only
    speculation, was to the mechanics of the dark accelerators. You stated I 'made up' any connection between dark accelerators and dark matter, asked if I had any 'credentials' to make such an analysis. No, I have no 'credentials' and the analysis
    was NOT MINE, but current science which you are ignorant of. AGAIN, from The CERN
    Courier, reduced to three lines so maybe you won't get lost reading a whole paragraph:

    "The Galactic Centre has long been predicted as a source of VHE gamma rays generated in the accumulation and annihilation of dark-matter particles, for example the lightest stable supersymmetric particles. The characteristics of the gamma-ray signal detected by HESS are indeed consistent with the expected features for dark-matter annihilation"

    No, Aer, dark matter does not emit any detected EM radiation. ANNIHILATION of dark
    matter particles was predicted to produce gamma-rays. Kapeesh?

    Now Aer, what are your 'credentials' that allow you to reject evidence of dark matter,
    evidence that you are not even aware of? Get real.
     
  15. Aer Registered Senior Member

    Messages:
    2,250
    I know not perfectly well ANYTHING that I have distorted!
    You said that dark matter is UNDENIABLE. Very well I say, so where is the PROOF? There is no proof you say - then you claim there is evidence as if that is somehow DIFFERENT from proof.

    evidence: stand as proof of


    I see you have nothing to say to the above! Might it be because I've distorted NOTHING? (I do think that is the case!)


    Is gravity a SUBSTANCE that we can detect? Some people think so, but they haven't been able to prove it. General Relativity says that gravity is the curvature of spacetime. Dark Matter "evidence" as you call it is not analogous to the evidence for gravity unless you want to claim that gravity is a substance that we just cannot detect.


    Very good question! It seems you want to say that gravity is a substance when all the evidence we have says it is the curvature of spacetime. Nice try though - I liked it!

    The strength of the curvature it produces determines this. Duh.


    It produces the effect of.... gravity! Right? It is called "dark" matter because it produces the same gravitation effect that ordinary matter does - It's just that it cannot be detected. Now here is the shocker: Dark matter could exist and not have anything to do with the dark accelerators you speak of as evidence for dark matter. Of course, I doubt your weak mind will be capable of comprehending this statement. You'll probably ignore it or make some stupid argument that dark accelerators can only be explained in conjunction with dark matter.


    I never said dark matter and dark energy were the same! I used the wrong term, ONCE, and you twist that to be that I don't know the difference! Go back and read the thread, I referred to dark matter and dark energy in the appropriate context everywhere else.




    Don't talk to yourself - problem solved.

    And the mechanics you mentioned for dark accelerators included the use of dark matter WHICH IS SPECULATION AS WELL.



    No! I assumed you made it up since there was no reference in the article to what you were talking about. It wasn't until LATER that you linked to another article that contained the speculation you referred to. Don't believe me? Here is the quote of what I said:
    And this is the only time I ever mentioned that you 'made it up' - since you've provided your reference after the fact, I wouldn't be so stupid as to hold on to an assumption that you 'made it up'

    Please Register or Log in to view the hidden image!

    though you are so stupid as to believe that I still think that you 'made it up' as you keep brining this up (4 or 5 times?).


    Yes, this is a perfectly good explanation. That doesn't lead to the conclusion that it is correct and there is no other possible explanation.



    How many times do I have to tell you this? I am not rejecting the possibility of dark matter!

     
  16. 2inquisitive The Devil is in the details Registered Senior Member

    Messages:
    3,181
    Aer, the kind of 'PROOF' you seem to be demanding exists for little in physics. Strong
    evidence, conforming to theoretical predictions, is all that is necessary for much of physics. Do you believe there is sufficient evidence for the existence of neutron stars, for instance? Do you have a cup of neutron star in your lab to measure? There is strong evidence for 'something' existing that be easily detected by the gravitational
    influence it has on baryonic matter. Unlike baryonic matter, it cannot be detected by
    the EM radiation it gives off or absorbes. Are you aware of the observed 'filaments' of gas clouds
    stretching out to great distances from some galaxies into 'empty' space? Without a
    significant source of gravity 'anchoring' one end in space, the filaments would have
    collapsed into the galaxy long ago. The source of the gravity cannot be detected by
    EM radiation, hence it is named 'dark matter'. It is just a name given something known to exist by its observed influence, but its exact composition is not known. Again, I said
    the existence of 'dark matter' SEEMED undeniable to ME. I am unconcerned with your
    demands of a 'proof' that meets YOUR criteria.
    ================================================================

    by Aer:

    "Yes, this is a perfectly good explanation. That doesn't lead to the conclusion that it is correct and there is no other possible explanation."
    =============================================================

    I agree that the annihilation of dark matter particles is not the only possible explaination
    for the emission of VHE gamma-rays that are a million million times as energetic as visible light. VHE gamma-rays traced to two different regions of space where nothing
    is detected to exist. Could it be an invisible dragon belching them out? I don't think so,
    what is your plausable explaination? My original speculation followed from the prediction
    that annihilation of dark matter particles would result in the gamma-rays.
     
  17. Aer Registered Senior Member

    Messages:
    2,250
    WRONG. This kind of proof exists for everything that is UNDENIABLE in physics. If you want to claim dark matter is undeniable - you better present extraordinary evidence. PERIOD.

    Dark matter is just a concept introduced to explain the phenomenon you mention. That is where the concept came from - unexplained phenomenon. It has yet to be detected and thus proven. Geesh!
     
  18. everneo Re-searcher Registered Senior Member

    Messages:
    2,621
    But local ether is a special exception and does not require any extraordinary evidence of existence, but can spawn a vaild theory! you are such a joker.
     
  19. 2inquisitive The Devil is in the details Registered Senior Member

    Messages:
    3,181
    by Aer:

    Dark matter is just a concept introduced to explain the phenomenon you mention. That is where the concept came from - unexplained phenomenon. It has yet to be detected and thus proven. Geesh!
    ===============================================================

    Yes, dark matter was introduced to explain observed anomalous gravitational effects.
    You seem to be unaware that evidence for dark matter is nowadays more than
    just the gravitational effects. Here is a paper presenting results (expected) of neutralino annihilation in the dark matter halo surrounding the Large Magellanic Cloud, our
    galatic neighbor. Note: The gamma symbol reproduced as a 'g' in the cut & paste.

    "Abstract. I present results on the expected g-ray and synchrotron fluxes due to neutralino annihilation
    in the LargeMagellanic Cloud based on [1].
    1. INTRODUCTION
    Decades of observational evidence indicate that galaxies are surrounded by massive dark
    matter halos. Of the many candidate dark matter particles that have been proposed,
    the most popular is the neutralino, c. Products of c¯c annihilation rapidly decay into
    neutrinos and g-rays, as well as electrons and positrons which emit synchrotron radiation
    in local magnetic fields. At a distance of 50.1 kpc [2], and given a wealth of observations
    indicating the existence of significant amounts of dark matter [e.g., 2, 3], the LMC is an
    obvious choice for neutralino detection.
    The flux of both g-ray and synchrotron emission from neutralino annihilation in the
    LMC depends on the square of the density profile of the LMC dark halo. To obtain the
    density profile we fit the rotation velocity HI data from Kim et al. [4] and carbon star
    data from Alves and Nelson [5]. We considered a range of density profiles, but here I
    discuss only the Navarro, Frenk and White (NFW) [6, 7] profile, and a shallower profile
    – an isothermal sphere with a core as derived in [5] by fitting the same LMC rotation
    curve data we used. This profile represents a less ideal scenario. Instead of making the
    assumption of a minimum disk, the stellar disk and gas contributions are included in
    the model, hence the contribution from the dark matter is confined to smaller values
    compared with the minimum disk assumption. More details on the various fits to the
    observed rotation curve are given in [1]."

    edit: forgot link: http://arxiv.org/PS_cache/astro-ph/pdf/0502/0502253.pdf
     
    Last edited: Aug 19, 2005
  20. Aer Registered Senior Member

    Messages:
    2,250
    2inquisitive, we've already been over this. Cosmology and Astronomy are not my thing - look what forum we are in, not the Cosmology and Astronomy forum! What part of the following statement made by myself do you not understand:
    Here, I will spell it out for you. The red indicates that I have no problem being called ignorant of the latest and newest support regarding dark matter - because I am not that interested in it and do not follow it. The blue says that I did in fact try to search for this evidence. Now I'll be the first to admit that I don't go as in depth of a search as you do, because like I said in the opener sentence, I am not much interested in it. But when I find physicists claiming they have no evidence that dark matter really exists, that is good enough for me.

    Now this is the point in which I think you get confused. You seem to think that I am denying that dark matter exists when really I am not. I have no reason to deny that it could exist, but I'll wait for the physics explanation.
     
  21. 2inquisitive The Devil is in the details Registered Senior Member

    Messages:
    3,181
    by Aer:

    "2inquisitive, we've already been over this. Cosmology and Astronomy are not my thing - look what forum we are in, not the Cosmology and Astronomy forum! What part of the following statement made by myself do you not understand:"
    =====================================================

    You do seem confused, Aer. Modern physical Cosmology had its beginnings with Einstein's General Theory of Relativity. It is the study of the evolution
    and large scale structure of the universe. But Dark Matter properties are not
    the domain of Cosmology or Astronomy. This study is most often done in the
    disclipines of High Energy Physics or Astrophysics. The above paper was published in the Astrophysics Journal.

    The reason I keep referring to these articles is because YOU refuse to accept
    that Dark Matter is fully accepted as existing as a fact in modern physics. By
    'modern', I mean the physics of the last very few years, not 90 year old theory. The 'search' is for the different 'types' of particles. Just as baryonic
    matter is not composed of only one particle, Dark Matter is predicted to be
    composed of more than one particle type. I particularly like the acronym for
    one of the latest particles, the WIMPZILLA, ha! Here is a cut and paste and link to new paper, published August 1, 2005, wherein Dark Matter is accepted as a fact and the proposed particle is a superheavy relic left over from the inflationary epic of
    the Big Bang. Are you aware that some Ultrahigh energy cosmic rays violate
    the GZK cutoff? Do you know what the GKZ cutoff refers to?

    Introduction
    The nature and origin of the dark matter in the universe and the origin of ultrahigh energy cosmic
    rays (UHECR) are certainly two of the most interesting problems of astroparticle physics, and maybe
    even of physics, at the beginning of the 21st century.
    The three puzzles related to the origin of cosmic rays with energies beyond the Greisen-Zatsepin-
    Kuzmin cutoff, E > EGZK ≃ 4 × 1019 eV, are:
    1. Scattering off cosmic microwave background photons limits the penetration depths of charged particles
    at these energies to distances < 100Mpc [1, 2, 3];
    2. the distribution of arrival directions of UHECRs does not seem to favor any known astrophysical
    sources within the GZK cutoff length;
    3. it seems extremely difficult to devise sufficiently efficient astrophysical acceleration mechanisms
    which could accelerate particles to energies E > EGKZ, and at the same time overcome collisional
    and radiation losses.
    The so called top-down models of UHECRs combine both problems by proposing that ultrahigh
    energy cosmic rays arise in the decay [4, 5, 6, 7, 8] or collisional annihilation [9, 10, 11] of superheavy
    dark matter particles. We will use both the acronym SHDM and WIMPZILLA1 for superheavy dark
    matter particles"

    http://arxiv.org/PS_cache/hep-ph/pdf/0508/0508025.pdf
     
  22. Aer Registered Senior Member

    Messages:
    2,250
    Dark matter was introduced to explain the gravitational effects galaxies seem to produce. So yes, dark matter fits in with cosmology.

    cosmology: the astrophysical study of the history, structure, and dynamics of the Universe.

    Oh look at that - astrophysical.

    Please Register or Log in to view the hidden image!

    Why do you need to nitpick at semantics? It is really a useless excercise, especially with regard to cosmology. You were the one that brought up cosmologists and astronomers - that is why I refereed to them.

    I think I will stick with what I said:
    2inquisitive, we've already been over this. Cosmology and Astronomy are not my thing - look what forum we are in, not the Cosmology and Astronomy forum!

    Perhaps it is you who is confused.


    Ahh yes, the defining moment, what is dark matter? That is what physicists wish to answer, yet they cannot even detect it. You keep bringing up new articles because you have a facination with the subject for some reason. Might I suggest you head over to this forum to discuss these matters. I have no interest in reading the articles you link to. You keep insisting that I am refusing to accept that dark matter may exist when all I've said is the contrary. The reason I hesitate to say it is undeniable is because it may turn out to be entirely different from what we expect. It could be so exotic that "matter" is not a proper description for it. But that is for physicists to work out - and at the moment, it appears they don't really have a whole lot to go on other than speculation.
     
  23. superluminal . Registered Senior Member

    Messages:
    10,717
    The effects of "dark matter" which we observe, could indeed be attributable to something other than actual mass being present. Gravity behaving differently on extremely large (or small) scales for instance.
     

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