Einstein's Telescope (General Relativity) Still "Annoyingly" Solving Puzzles

Discussion in 'Astronomy, Exobiology, & Cosmology' started by danshawen, Jun 15, 2017.

  1. danshawen Valued Senior Member

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    https://arstechnica.com/science/201...ingly-right-as-researchers-weigh-white-dwarf/

    The gravitational lensing effect predicted by General Relativity has become one of the most powerful tools in Astronomy. As detailed in "Einstein's Telescope" by Evalyn Gates, the Hubble Space Telescope has become one of the most powerful instruments in astrophysicist's toolbag because it is capable of doing interferometry on the multiple images of the same object caused by gravitational lensing.

    An international team of astrophysicists recently had a problem with the calculated age of Stein 2051 B, which appeared to be unreasonably light for a white dwarf star which is known to be bereft of the fusion process that produces iron. In order to be as light as originally calculated, Stein 2051 would have had to be quite old, on the order of the age of the universe. The problem presented itself this way. If you know the mass and the temperature of a white dwarf star, you can predict its radius, and also its age. If a white dwarf is too close to its neighbor (a binary star system), this analysis is in practice quite difficult to do.

    Enter Hubble's gravitational lensing interferometery upgrade. When four of the gravitationally lensed images of another star eclipsed by Stein 2051 B were compared to the predictions of General Relativity, the mass of Stein 2051 B was placed at 0.67 times the mass of our own Sun, making it a typical white dwarf star in every respect, and especially with respect to its calculated age.

    Some of the researchers registered annoyance at the continued unreasonable reliability of the predictions of General Relativity. Einstein's telescope remains the most powerful tool available for doing basic astronomy.
     
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  3. Q-reeus Valued Senior Member

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    The ArsTechnica article headline declares "Einstein still annoyingly right as researchers weigh white dwarf". Which is all too familiar pro-GR PR and annoying since even Newtonian gravity predicts gravitational lensing albeit at half the value of GR. A host of rival metric gravity theories will all agree to an accuracy far exceeding what a lensing effect owing to a white dwarf could distinguish between. As repeatedly stated elsewhere, it's doubtful even after many upcoming EHT measurements of the central massive object in Sagittarius A*, GR gravity will be convincingly distinguished from numbers of rival theories.

    Best bet likely remains detailed analyses of beyond-NS-masses binary merger event GW's, particularly once enough detections come in from detectors additional to aLIGO ones.
    There is speculation at least many FRB's (Fast Radio Bursts) are associated with merger events: https://en.wikipedia.org/wiki/Fast_radio_burst#Origin_hypotheses
    If confirmed, that will greatly strengthen gravity theories such as Yilmaz gravity that allow intrinsic magnetic fields for what in GR have to be BH's lacking any such intrinsic magnetic moment.
     
    Last edited: Jun 15, 2017
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  5. danshawen Valued Senior Member

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    For those unfamiliar with the differences between Yilmaz' theory of gravitation and General Relativity, GR predicts that black holes (of lower radii, masses) exist, especially like the ones at the center of our own galaxy.

    Yilmaz' theory, on the other hand, negates the idea of black holes with the exception of hypermassive ones, inside the event horizons of which, normal atmospheres or even whole universes like our own could theoretically exist.

    In part, it was the idea that the known universe contained enough mass / energy to exist within the GR construct of a black hole that instigated Yilmaz to propose his theory of gravity, and this estimate that we may be living inside of such a beast was determined long before either dark energy or dark matter were proposed as solutions to the supernovae 1A accelerated expansion or anomalous spiral galaxy rotation, respectively.

    At least two other hypermassive black holes inside of this universe have been discovered, each of which appear to have more mass than would be possible if they had swallowed outside mass at their current rate since the era of the Big Bang (or inflation). Their respective locations preclude the possibility that these objects will ever eclipse anything they have not already swallowed, so Einstein's telescope is next to useless to determine their respective masses with any certainty.

    If Yilmaz gravitation is the correct formulation, the Big Bang itself may have been an artifact of the initial collapse of the hypermassive black hole that is our universe.

    Cosmology seems to be enough of a mess right now with Guth's faster than light inflation preceding the era of the Big Bang. Don't you know, all of the free parameters, the speed of light included, were different back then? Throwing Yilmaz' hypermassive black hole universes into the cosmological mess would be like pouring gasoline onto a train wreck.

    Unlike any other area of scientific inquiry, more observation applied to cosmology only seems to produce more cosmological speculation than answers to simple questions of a more limited scope. This is something else that 21st century mainstream cosmology seems to have both in abundance and in common with other forms of superstition.

    We were probably better off and closer to the truth with the relative certainty of those gargantuan turtles than we currently are with the 10^116 uncertainty in Vacuum expectation Value.

    Hopefully, current efforts to produce a sharper image of the Saggitarius black hole may shed some light on the existence of black holes for those still unconvinced that they exist, even if whole galaxies, dark matter included, seem to be orbiting something we can't actually see. Whatever it is we see, cosmologists seem determined to see something else.
     
    Last edited: Jun 15, 2017
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  7. Q-reeus Valued Senior Member

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    Sort of, except the only lower BH radius is for a hypothetical Planck mass BH whose supposed Hawking radiation means instant evaporation. 'Realistic' astrophysical BH's are another matter.
    Again, 'sort of'. In Yilmaz gravity there are no horizons anywhere, hence no such thing as a 'hypermassive BH'.
    News to me. Care to cite a reliable source for such a claim?
    Again, any reliable source to back this claim?
    Leaving aside any quibble over 'BH' or whatever they truly are best labelled, quite probably true. Given feeding rates would naturally be expected to decline with time.
    Oxymoron repeated. No BH's, nor any cosmic horizons in Yilmaz gravity - period.
    Seems to me we have a train wreck right here, of sorts.
    If you say so Dan. What disturbs a little is not getting any email notification of your post. Could be a subtle hint of things to come. Whatever. Have a nice day, ok!
     
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  8. danshawen Valued Senior Member

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    I received no notification of yours either. They've been a little late of late.

    I'll try to find the refs you requested, but most likely I read them once and forgot the source. Lee Smolin wrote a whole book on the subject of the evolution of black hole universes, but as I didn't really like that one, I don't cite it very much, if at all. I don't remember him citing Yilmaz at all, but I could be wrong about that.

    You convinced me to remember Yilmaz by pointing me in the direction of one of my old mentors, Carroll O. Alley (famed for flying atomic clocks in planes to confirm GR long before GPS). Another feather in Einstein's and GR's cap, right there. Yilmaz and Alley co-wrote a paper or two, so if Yilmaz didn't respect GR as much as Alley, I'm sure he had good reasons. Thanks again for that.

    There used to be folks here who cared very deeply about cosmology. I don't. It is what it is, and does not affect a single nanosecond of my very brief lifetime, even if our whole universe was on the precipice of abruptly coming to an unsanctimonious end. What could anyone do about it? Slow down the rate of global warming, perhaps, for all the difference it would make.
     
    Last edited: Jun 15, 2017
  9. danshawen Valued Senior Member

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    https://en.wikipedia.org/wiki/List_of_most_massive_black_holes

    http://www.sciencemag.org/news/2015/12/limit-how-big-black-holes-can-grow-astonishing

    You may have noticed, there is a considerable discrepancy between the masses of black holes in the Wikipedia list and the Science article quoted size (50 billions of solar masses) at which point the acretion disk starts clumping into stars, slowing the acretion process somewhat (how? by means of stellar wind?).

    Even if I cited a source for every one of the statements you requested a reference for, it means exactly nothing because as far as I can tell, all of this black hole discussion is sheer guesswork. Part of the problem might be that some researchers are using GR to make their predictions, while others prefer to use something else. There is no shortage of theories of gravitation to choose from:

    https://en.wikipedia.org/wiki/Category:Theories_of_gravitation

    Here is the closest equivalent to something I read too long ago to remember about the density inside of a hypermassive black hole:

    http://io9.gizmodo.com/the-more-mass-you-add-to-black-holes-the-lighter-they-1680822945

    Here is the applicable excerpt:

    "This leads us in strange directions. A black hole with the mass of 387 million of our suns would have the average density of water. And, according to some, a black hole with the mass of our universe would have the average density of our universe — meaning that getting swallowed up by a black hole isn't quite as bad as it sounds."

    A hypermassive black hole (about 20 trillion solar masses) in the Phoenix cluster (5.7 billion light years distant) seems to be accreting about 60 million solar masses per year. By my calculations, this is a little over 100 solar masses accreted per minute, so why don't we see any gravity waves from that process? Is the thing swallowing mostly dust?
     
    Last edited: Jun 15, 2017
  10. Q-reeus Valued Senior Member

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    It was never a question of respecting GR or not, but having a fully consistent theory. Carroll Alley iirc became a fan of Yilmaz gravity whilst in charge of the Lunar Laser Ranging project. Yet again, the ppt article setting out all of Alley's reasoning for choosing Yilmaz gravity over Einstein's GR: http://www.powershow.com/view/1bbc8-ZjhlZ/P1246341516SeoJH_flash_ppt_presentation
    Sean Carroll is on record as stating 'we' now understand GR far better than Einstein himslef did. Similarly, I'm now convinced that Stan Robertson understands Yilmaz gravity better than did the late Yilmaz himself, or the late Alley, or anyone else who has investigated it.
     
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  11. Q-reeus Valued Senior Member

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    At 3 orders of magnitude larger than anything else I've heard of, that claim definitely needs backing from a reliable source.
     
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  12. danshawen Valued Senior Member

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    Check the table in the Wikipedia link.
     
  13. danshawen Valued Senior Member

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    Great reference! I was wondering who exactly was left to carry on this work. I am familiar with Dr. Alley's involvement in the laser ranging project as well. Nice to see that he is as fondly remembered by others as I remember him.
     
  14. Q-reeus Valued Senior Member

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    Just have. You have another look Dan. In descending mass order, that list has S5 0014+81 as current record holder at ~ 40 billion solar mass.
    Your '20 trillion' one, in the Phoenix cluster, is at 6th spot with actually a 'mere' 20 billion solar mass. You've been too naughty.
     
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  15. danshawen Valued Senior Member

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    No. Look at the right hand column of that entry:

    "This black hole is continuously growing at the rate of ~60 M☉ per year."

    Divide 60,000,000 by 365, divide that by 24, divide that by 60, you get about 114 solar masses per MINUTE, see? Where are you getting your numbers?
     
    Last edited: Jun 16, 2017
  16. Q-reeus Valued Senior Member

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    You mistake what M☉ means. Solar mass, not one million solar mass. Further, linearly extrapolating an estimated 'current' mass influx rate to span over billions of years is likely to be wildly out. Anyway, the left most table entry unambiguously has the mass at 20,000,000,000 M☉. Recall also the second linked article in your #6 estimated a super massive 'BH' upper bound of ~ 50,000,000,000 M☉.
    PS: Once again - NO EMAIL NOTIFICATION!!
     
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  17. danshawen Valued Senior Member

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    Yes, I see that now. Off by a factor of 1 million. Not the biggest one, but that makes perfect sense now. Thanks for the homework help!

    Better yet, the notifications seem to be working again!
     
    Last edited: Jun 16, 2017
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  18. danshawen Valued Senior Member

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    Today in the Washington Post, another article on the same finding appeared with the 'alternative' news headline:

    "Astronomers happily prove Einstein wrong", alluding to Einstein's remark relating the rather slim chances that the method of the gravitational lensing of eclipses inspired by him, and the one we are now using, would ever prove useful for estimation of stellar masses, of which this white dwarf is possibly the best example.

    Einstein only said:

    "There is no hope of observing this phenomenon directly."

    He probably should have known better, because the technique used by Hubble to observe this takes a page on interferometry right out of the Michaelson-Moreley playbook, the experiment whose null result gave us his Special Theory of Relativity.

    Kind of a misleading headline though, I think anyone would agree. His off the cuff remark about the experimental capabilities of his day was wrong only because he could not have imagined what Hubble can do, but the technology is due to his vision and would not have been possible without him.
     
    Last edited: Jun 19, 2017

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