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The Dark Flow & the Existence of Other Universes -New Claims of Har

  1. Jun 1, 2013 #1
    The "Dark Flow" & the Existence of Other Universes --New Claims of Har

    I just saw this big news story, "The "Dark Flow" & the Existence of Other Universes --New Claims of Hard Evidence" and thought that others would be interested in hearing this here. Dark Flow isn't new is it? Is this bold heading justified?


    http://www.dailygalaxy.com/my_weblo...er-universes-new-claims-of-hard-evidence.html
     
  2. jcsd
  3. Jun 1, 2013 #2

    phinds

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    I thought dark flow had been discredited years ago, no?
     
  4. Jun 1, 2013 #3
    I don't know. I thought it was just that the jury was still out pending more measurements and analysis, but could be wrong about that.
     
  5. Jun 1, 2013 #4
    Gotta love how the crack pot ideas come out of the woodwork due to the planck results. Lol
     
  6. Jun 1, 2013 #5
    Kashlinsky has a Ph.D. from the Institute of Astronomy, University of Cambridge, England
    and works at
    Observational Cosmology Laboratory
    Exploration of the Universe Division
    Goddard Space Flight Center, Greenbelt,
    MD 20771

    So if you disagree with him its one thing, but calling his work crackpot is not right.
     
  7. Jun 1, 2013 #6
    Yea your right I'll retract that part. Its just that numerous articles (particularly multiverse)
    theorem have been hitting the internet over the planck data.
    I've even seen some hit the day after its release. As such I'll wait to further confirmation regardless of how seemingly plausible. In some ways it reminds me of Cern and its neutrinos faster than light mistake. Numerous articles showed up, until they realized it was an error. Not saying this is the case here, but I consider any proposals based on the planck anistrophies speculative prior to confirmation of those anistrophies ie from further testing.
     
    Last edited: Jun 1, 2013
  8. Jun 1, 2013 #7
    The existence of other universes or rather, other 'multi-billion light year mega clusters' could be inferred from a cold spot but it remains firmly in the realm of conjecture - A very long way from hard evidence.

    That is not to say I don't like the idea because I do like it. The implications are truly breathtaking though with many strongly established theories threatened with being blown away.

    An often asked question among students of cosmology and GR is, is universe itself a black hole? The generally accepted answer to that is no. Unintuative notions are profered such as 'the big bang singularity is in the past not the future'.

    The next question would then be were we ever in a black hole? After all the Swartzchild radius of the (observable) universe has been calculated in the billions of light lears (An article in Wikipeadia says 10 billion). Certainly for a good chunk of our history we would have been inside this radius.

    Again the accepted answer is no. This time though the supporting theory is even more counter intuative. Something about there being no time or space outside the universe. In spite of this being true by definition it fails to answer the question because that question isn't about the universe, only the observable universe.

    If the cold spot were due to another mega cluster this would mean that outside our observable universe/mega cluster there was time and space - and that would mean we were at one time within our own Swartzchild radius and that today we are not. This would require a new theory of what lay inside a black hole as there is no apperent mechanisum for a singularity disruption.

    There are uncertainties concerning current theories anyway. There are unresolved issues concerning quantum mechanics. There are further problems as well. For example, in the infinite series of say integers, one value is conspicuous by its absence, that of infinity. It would seem to be a fundamental law. A range can be infinite but a real value cannot be? In any event, by definition of the event horizon, any theory concerning the inside of a BH will always be conjecture. But the conjecture of a singularity would have to change if it became nessesary to embrace BH disruption.

    One possible candidate is that all real BHs spin and that this prevents a singularity (rather than allowing a ring singularity for QM reasons). If for whatever reason the spin falls below some critical value (eg losses due to frame dragging the outside), then collapse can go to completion but again for QM reasons everything must convert to photons. The instant this happens the photons begin an outward journey because although they excert gravity there are 'transmission' issues with gravity being unable to outrun light (not well put I admit)

    Such theories are outrageous but would have to be considered to explain how a BH could begin expansion. We may get lucky and catch a BH exploding as a Gamma Ray burst. If we develop better telescopes and better detection techniques it may turn out that the GRBs are far more powerful than current estimates and are in fact, BH disruptions.

    So as I said, a long long way from 'hard evidence' but very exiting nonetheless. Outrage is just a silly emotion anyway and as a consolation to the diehards, at least they won't have to invent more darkness. We have had dark matter (again better telescopes please), dark energy (horrible). But without other mega clusters and hence exploding BHs we will have to have dark thermodynamics as well!
     
  9. Jun 2, 2013 #8
    I agree with you that other universes is the most speculative explanation that one could possible think of when trying to explain and analyze these initial observations. Cosmologists do like to think big and it sparks peoples attentions and imaginations so I think it is reasonable to mention it as a possibility, but the news releases seldom present things that way. However they should also define what they mean by other universes because it is possible that what some call every a multiverse could still be The Universe in one definition.

    The initial black hole description you mentioned is also interesting. Perhaps this state might have existed for an eternity before something caused it to begin inflation.

    Perhaps what gets people most vocal is that this dark flow observation could mean changes are needed to the standard model and when you have to add on fixes to a theory to hold it together, that can sometimes mean that there is something wrong with it.

    Could it be something as simple as dark energy expansion is not constant everywhere? If this is a silly idea please I am only amateur reader here.
     
    Last edited: Jun 2, 2013
  10. Jun 2, 2013 #9
  11. Jun 2, 2013 #10
    So called 'dark energy' to explain the expansion of the universe makes me very uncomfortable as it breaks the principle of Ocam's razor. Loosely put, this states that entities should not be introduced unless they are absolutly nessesary. If we take the nutrino for example, these were predicted to bridge an otherwise inexplicable but observed energy gap in nuclear reactions. At stake was mass energy equivelence which is way too fundamental to loose. And as we know, the nutrino turned out to be real.

    I don't think the observed expansion of the universe yet needs dark energy and it certainly does not in any way shape or form, need the 'multidimensional multiverse'. I put my absolute faith in Einstein's GR and look for [3D + time] models of the [obversable] universe that would be allowed in GR.

    And one does not have to look very far. In GR space itself is contrated in a gravity field. A collapsing gravity field thus will cause the opposite. The big bang would create such a collapsing gravity field if it were really an exploding BH.

    Scientists have always been human and humans can be delusional at times! They are prone to thinking they are at the center of things and of thinking too small. The idea that there is nothing outside the future light cone of the Big Bang is conjecture. It is very established conjecture but conjecture nontheless. It is frequently asserted as fact and scientists can risk thier jobs if they point this out.

    I too am human of course and I too, have emotional attachment to particular theories. I make no bones about seeking a theory of BHs that allow them to explode so that the big bang is not a special case. But the difference between me and others is that I know I can be deluded and don't trust myself. In psychology there is such a thing as a 'belief system'. This causes our existing beliefs to be reinforced by limiting our interpretation of what we see around us to within those beliefs. Thus to me, the cold spot could be another mega cluster. To another there must be some other explanation. Both sides must be aware of the extent of thier conjecture. In short it is never good enough for us to observe the universe. We have to obvserve ourselves obversing the universe!
     
  12. Jun 3, 2013 #11
    Exploding black holes is an interesting idea. Did they used to be called white holes or is this different?
    I think that a white hole as a cause of the BB has already been refuted?
    Also I am not sure if exploding may be the description term for the BB since it happened everywhere.

    In general I fully agree with your views on Ocams Razor, couldnt agree more.


    Regarding "The idea that there is nothing outside the future light cone of the Big Bang is conjecture. It is very established conjecture but conjecture nontheless. It is frequently asserted as fact and scientists can risk their jobs if they point this out".

    I disagree, I have never heard anyone saying that extent of "The Universe" is identical to the size of the light cone. That would be a large coincidence. Some Cosmologists even think the observable universe is only 10^-32 times the size of the whole.

    Agree with you about observing ourselves and our biases. As a designer I think the correct approach for Cosmolgists here is to Brainstorm every possible idea for describing the way the universe came into existance and its present and future states. Then they should rank them and present full arguments for why these ideas are or are not useful.

    Back on topic about dark flow, the cold spot could be another mega cluster, would it mean that we have to change our views on the scales at which the universe is istropic and homogeneous and could this cause a problem for the standard model?

    http://en.wikipedia.org/wiki/Cosmological_principle
     
  13. Jun 3, 2013 #12
    instead of relying upon a pop media article why not look at professional papers to "Observational evidence???

    http://arxiv.org/abs/1303.5090 Planck intermediate results. XIII. Constraints on peculiar velocities

    no evidence of "dark flow is found in the Planck results.

    http://arxiv.org/pdf/1303.6614v1.pdf "On the Statistical Significance of the Bulk Flow Measured by
    the PLANCK Satellite"

    http://www.astro.ucla.edu/~wright/dark-flow-errors.html "Dark Flow Detected - Not!" not quite professional as its Ned Wright's site and written for a non technical audience.
     
  14. Jun 3, 2013 #13
    This requires some correction. First off dark energy was surmised long before becoming accepted.
    Dark energy for that matter isn't really mysterious. If you think of it in terms of negative pressure it makes absolute sense. energy density per volume and pressure are identical terms.
    The cosmological constant is absolutely needed without it we could not account for expansion. The only competing model to that and trust me its not much of a competition is MOND. Mond works only in special circumstances.
    Your lightcone statement makes little sense the "Observable universe" is what exists in out lightcone. Move 100 Mpc less or more makes no difference you will have a different lightcone.

    Lightcones depend on the Observer. They only describe light pathways that can reach us. We do not think that nothing exists outside of the light cone.
    We also do not think we exploded from a Blackhole. such an event would have a preferred direction for another black holes are not known to explode they whimper away via Hawking radiation but only when the surrounding temperature is less than the black body temperature.

    here is some recommended reading material

    http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf "Misconceptions about the Big bang" also Lineweaver and Davies
    http://arxiv.org/abs/astro-ph/0310808 "Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe" Lineweaver and Davies
    http://arxiv.org/abs/1002.3966 "Why all these prejudices against a constant?"
    http://arxiv.org/abs/1304.4446 "What have we learned from observational cosmology ?"
     
    Last edited: Jun 3, 2013
  15. Jun 3, 2013 #14
    A white hole is the theorized exit of a blackhole via a wormhole its never been observed, and no evidence exists of such.

    the dark flow challenges the preferred direction portion, but as I mentioned its still not confirmed as valid. Particularly in regards to observational evidence.
     
  16. Jun 3, 2013 #15
    "Instead of relying upon a pop media article why not look at professional papers to "Observational evidence???"

    I wasnt relying on anything for anything. I was simply passing on this news that there are new claims. Others here are in a better position than I to judge for themselves (and me) whether the claims are new or have any merit.
     
  17. Jun 3, 2013 #16
    fair enough the papers I provided, should assist you in that judgement. particularly the first post.
    the second post is simply good articles to help clear up "standard cosmology" as opposed to
    misconceptions. Dark flow if I recall was first surmised in 1973. It never did get very far, lots of controversy etc. Yes there are findings that offer some support for it however their is far more data that argue against it. In that sense its similar to MOND. though unrelated

    I forgot to mention their was a proposol that the universe exists inside a black/whilte hole. By Poplowski. Its also popular on the net, again no supportive evidence. just FYI

    edit: I don't know if this is the article your fist link is referring to its the latest I can find at arxiv
    by Kashlinsky http://arxiv.org/abs/1211.4345
     
    Last edited: Jun 3, 2013
  18. Jun 3, 2013 #17
    I can only make a very quick comment tonight. I take the point about lightcones. A poor description indeed. It does not detract though, from the notion that there is no time or space outside that which arose from the big bang - A notion I prefer to keep an open mind about.

    As for the idea that a BH may be able to explode, I am talking here not of white holes (I am a 3D+time diehard) nor of Hawkins Radiation, instead I am refering to the QM issues regarding the formation of a singularity. As this matter remains unresolved (as far as I know), it is possible that BHs are only stable when spining as this may prevent complete collapse and thus complete conversion of matter to photons. I would agree though, with anyone who pointed out that there was no clear mechanisum by which 100 percent conversion to photons would allow those photons to move outwards.

    But my contemplation of possible BH explosions is driven primarily by gamma ray bursts (rather than the existance of a cold spot which I agree, predates the Plank data). There is a sufficiently significant possibility that the total energy of these events has been grossly underestimated, both by hithertoo poor detection techniques and by the assumption we are seeing GRBs that are relativitically beamed, which may turn out to be false in some cases. A mass escape by photons could match the profile of some classes of GRB, would be poorly beamed (a disk at best) and would provide the high end gamma rays observed (some photons have the mess/enegy equivelent of a million hydrogen atoms). It is possible (although I agree a long shot) that some GRBs release several solar masses in energy. Should this turn out to be the case (we might one day get telescopes good enough to tell), then the exploding BH would have to be considered more seriously.

    Anyway I shall answer the other stuff later
     
  19. Jun 4, 2013 #18
    Ok let's discuss one scenario where BH's can loosely put explode.
    You mentioned you don't particularly follow Hawking radiation, which unfortunately I'll have to go into. As Hawking radiation is involved. Though keep in mind I'm certainly no expert. I've read articles that BH explode when it evaperates to a point where its mass is less than its Shwartzchild radius. I haven't heard of any other method.
    Blackholes evaperation is an incredibly slow process, for a Schwarzchild blackhole of 1 solar mass
    the evaperation process by Hawking radiation is 1067 years. Thats for an uncharged non rotating blackhole. Some key points on Hawking radiation which is a blackbody temperature. The smaller the BH the faster it will evaperate. So micro blackholes will evaperate faster. Also evaperation does not occur unless the blackbody temperature is greater than the surrounding temperature. So the blackbody temperature must be greater than 2.7 kelvin.

    The Hawking temperature is


    [tex]T = \frac{\hbar c^3}{8 \pi k G M}[/tex]
    The Schwartchild radius as
    [itex]r =2GM/c^2[/itex]. Combining this with its Hawking temperature is
    [tex]r = \frac{\hbar c}{4 \pi k T}[/tex].

    A BH whose black body temperature greater than the blackbody temperature of the universe ( CMB temp) roughly 2.7
    k. Will absorb energy from the
    higher back ground temp.

    Now when this explosion occurs
    the mass is greatly reduced so its more of a whimper.
     
    Last edited: Jun 4, 2013
  20. Jun 4, 2013 #19
    Mordred, I was aware although not in the detail you have given, that HR is a slow process and that for a BH bathed at it would be in the CRB, there would be a slow gain in mass rather than a loss. You use the phrase 'don't follow HR'. I'll be more forthright, I don't get HR!

    Nor am I seeking to assert that BHs explode (by another process). It might have sounded like that but I was intending to stop firmly short of this. I like the idea as it removes the need for the big bang to be a special case or for the big bang never to have been a BH etc - but I know perfectly well liking an idea has nothing to do with it's validity! All I was really saying is that to the best of my knowledge, there were QM issues concerning the formation of a singularity and that there are implications to this such that disruption of a BH had not been catagorically proven to be impossible. I am wrong about this?

    One thing I am very curious about, is what a BH singularity should they actually be formed, thought to consist of? Again I am looking for the text book answer, the prevailing assumption or assertion in academia. I would have thought that Pauli's exclusion principle would regire 100 percent conversion to photons or at least bosons of some form. I would also be more comfortable with Pauli's exclusion principle continuing to apply. I am not convinced by statements such as 'the laws of physics break down' at the singularity. But the professors might have better ideas and better math to back them up.
     
  21. Jun 5, 2013 #20
    Text book answer to what the singularity is made of is no one knows for sure.
    is it infinetely dense with no volume? Is it one planck length? Does it form into a
    string?

    To answer what viable particle composition would require knowing the above
     
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