Astronomers witness the dragging of space-time in stellar cosmic dance

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Jul 14, 2020.

  1. paddoboy Valued Senior Member

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    https://phys.org/news/2020-01-astronomers-witness-space-time-stellar-cosmic.html
    Astronomers witness the dragging of space-time in stellar cosmic dance:

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    Artist's depiction of 'frame-dragging': two spinning stars twisting space and time. Credit: Mark Myers, OzGrav ARC Centre of Excellence.

    An international team of astrophysicists led by Australian Professor Matthew Bailes, from the ARC Centre of Excellence of Gravitational Wave Discovery (OzGrav), has shown exciting new evidence for 'frame-dragging'—how the spinning of a celestial body twists space and time—after tracking the orbit of an exotic stellar pair for almost two decades. The data, which is further evidence for Einstein's theory of General Relativity, is published today the journal Science.

    More than a century ago, Albert Einstein published his iconic theory of General Relativity—that the force of gravity arises from the curvature of space and time and that objects, such as the Sun and the Earth, change this geometry. Advances in instrumentation have led to a flood of recent (Nobel prize-winning) science from phenomena further afield linked to General Relativity. The discovery of gravitational waves was announced in 2016; the first image of a black hole shadow and stars orbiting the supermassive black hole at the centre of our own galaxy was published just last year.

    Almost 20 years ago, a team led by Swinburne University of Technology's Professor Bailes—director of the ARC Centre of Excellence in Gravitational Wave Discovery (OzGrav)—started observing two stars rotating around each other at astonishing speeds with the CSIRO Parkes 64-metre radio telescope. One is a white dwarf, the size of the Earth but 300,000 times its density; the other is a neutron star which, while only 20 kilometres in diameter, is about 100 billion times the density of the Earth. The system, which was discovered at Parkes, is a relativistic-wonder system that goes by the name "PSR J1141-6545."

    Before the star blew up (becoming a neutron star), a million or so years ago, it began to swell up discarding its outer core which fell onto the white dwarf nearby. This falling debris made the white dwarf spin faster and faster, until its day was only measured in terms of minutes.

    more at link...........

    the paper:

    https://science.sciencemag.org/content/367/6477/577


    Lense–Thirring frame dragging induced by a fast-rotating white dwarf in a binary pulsar system:

    Abstract:
    Radio pulsars in short-period eccentric binary orbits can be used to study both gravitational dynamics and binary evolution. The binary system containing PSR J1141–6545 includes a massive white dwarf (WD) companion that formed before the gravitationally bound young radio pulsar. We observed a temporal evolution of the orbital inclination of this pulsar that we infer is caused by a combination of a Newtonian quadrupole moment and Lense–Thirring (LT) precession of the orbit resulting from rapid rotation of the WD. LT precession, an effect of relativistic frame dragging, is a prediction of general relativity. This detection is consistent with an evolutionary scenario in which the WD accreted matter from the pulsar progenitor, spinning up the WD to a period of <200 seconds.



     
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  3. paddoboy Valued Senior Member

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    from the OP link..............
    "Pulsars are super clocks in space. Super clocks in strong gravitational fields are Einstein's dream laboratories. We have been studying one of the most unusual of these in this binary star system. Treating the periodic pulses of light from the pulsar like the ticks of a clock we can see and disentangle many gravitational effects as they change the orbital configuration, and the arrival time of the clock-tick pulses. In this case we have seen Lens-Thirring precession, a prediction of General Relativity, for the first time in any stellar system."
     
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  5. Q-reeus Valued Senior Member

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    I used to be amazed at how popular but erroneous notions become so entrenched in mainstream thinking they become 'indisputable fact' with counter-positions almost impossible to find. Such is it with 'frame dragging' aka Lense-Thirring effect. Do a search using "are frames actually dragged by a spinning mass", and page after page after page contains only confirmatory remarks, e.g. third para within https://www.abc.net.au/news/science...oves-einstein-was-right-astrophysics/11903018
    ""This time we're seeing a spinning star at the centre of the system dragging the very fabric of spacetime with it," said astronomer and co-author Matthew Bailes of the Swinburne Institute of Technology."

    Wrong, as I explained back in: http://www.sciforums.com/posts/3636235/ (see also #14 there).
    The author below confusingly interchanges 'frame-dragging' and gravitomagnetism as though synonymous here:
    https://cddis.nasa.gov/lw17/docs/presentations/session1/01-ilrs_17thwslr_lares.pdf
    Nevertheless he correctly presents the core of the actual, consistent physics, neatly encapsulated beginning on logical p4, Opening with:
    "GRAVITOMAGNETISM: frame-dragging is also called gravitomagnetism for its formal analogy with electrodynamics".......

    Best that can be said in favor of 'frame-dragging' is that it's an illusory interpretation partially consistent with when say a free falling body is dropped initially radially above equator of a spinning body e.g. NS.
    Space is not a viscous fluid. Wikipedia https://en.wikipedia.org/wiki/Frame-dragging#Effects (linked to in earlier link to my earlier thread posts) has it right on that point at least:
    "Another interesting consequence is that, for an object constrained in an equatorial orbit, but not in freefall, it weighs more if orbiting anti-spinward, and less if orbiting spinward. For example, in a suspended equatorial bowling alley, a bowling ball rolled anti-spinward would weigh more than the same ball rolled in a spinward direction. Note, frame dragging will neither accelerate nor slow down the bowling ball in either direction. It is not a "viscosity". Similarly, a stationary plumb-bob suspended over the rotating object will not list. It will hang vertically. If it starts to fall, induction will push it in the spinward direction."
    Feel free to email any champions of frame-dragging as actual circumferential swirling/dragging of space/spacetime, akin to swirling of water about an immersed spinning tennis ball.
     
    Last edited: Aug 6, 2020 at 5:19 AM
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  7. paddoboy Valued Senior Member

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    Let's get down to the nitty gritty Q-reeus. Over a period now of many years, you have shown a dislike for GR, to put it mildly.
    Your first crusade was with Vector gravity, and it went on from there, with various criticisms of articles posted that were favourable to GR, and support for other articles not so favourable.
    The facts are that GR is being tested every day, and as of 6/8/20, it still is overwhelmingly supported and generally accepted.
    And while my expertise in this field is at an amateur status, I certainly do know that GR, GR type BH,s frame dragging are all validated and accepted parts of GR.
    My lack of skills may prevent me from actually critiquing your view of the subject, other then the facts I have already presneted and the reputable articles and paper.
    In short I don't accept your criticism and claims, and would suggest that if you truly believe this and other criticisms of yours are valid, that you write up a professional paper for proper peer review. Yes, I have suggested that before, and it still holds. Please lets not start with mainstream conspiracy nonsense among scientists, as I find that pathetic to say the least.
    Every young up and comer, would be breaking his or her neck to invalidate Einstein's GR, and as mentioned it is being tested every day, and keeps on emerging with flying colours.

    There are papers every day with proposals, theoretical applications, claims and such, both for and against, and if I come across one I find interesting enough, I will always post here whether in support of GR or otherwise.

    Also no one that I'm aware of said spacetime was a "viscous liquid" certainly used as an analogy, which I find nothing wrong with, just as the rubber balloon analogy and/or raisin loaf with regards to spacetime and gravity.


    Again, the meat in the sandwich is that GR is considered our greatest theory of gravity, and it seems there is no need or any real effort to change that.
    Again I raise the fact that if you believe you have something concrete, then take the right path in getting a paper printed and reviewed.

    https://www.worldscientific.com/doi/abs/10.1142/9789812779120_0006

    GRAVITOMAGNETISM AND FRAME-DRAGGING: THEORY AND MEASUREMENT:

    Abstract:
    After a brief introduction on frame-dragging and gravitomagnetic field, including an invariant characterization of gravitomagnetism, we describe the phenomena due to spin on test gyroscopes, test particles, clocks and photons. In particular we show that when different light beams are deflected by the mass of a rotating object, with angular momentum J, and then, by gravitational lensing, observed at a far point as different images of the same source with different angular positions, there may be a significant time delay between the different images due to the spin of the deflecting body. We then discuss the time delay in the travel time of photons propagating inside a massive rotating shell. We apply this time delay, due to the spin of the shell, to the case of gravitational lensing and we show that there may be an appreciable time delay between the arrival of different images at Earth. We then consider some astrophysical configurations: a typical rotating galaxy and a typical rotating cluster, or super-cluster, of galaxies; the spin-time-delay might be large enough to be detected at Earth. This phenomenon should then be taken into account in the modeling of the time delay of different images by gravitational lensing and might be measurable in some gravitational lensing images. The spin-time-delay might give a new observable in the study of the dark matter content in rotating galaxies and clusters.

    We then describe the latest results in the measurement of gravitomagnetism of Earth and Lense-Thirring effect by laser ranged satellites. Gravity Probe-B, launched by NASA on April 20 2004, will try to measure the Earth frame-dragging with accuracy of 1 % or better. A future accurate determination of the Lense-Thirring effect, at the level of 1 % accuracy, may be provided by the LARES/WEBER-SAT experiment to measure “frame-dragging” and to give other basic tests of fundamental physics and general relativity. Here we describe the 1995-2004 measurement of Lense-Thirring effect obtained by analyzing the orbits of the two laser-ranged satellites LAGEOS and LAGEOS II; this method has provided in 2004 a direct measurement of Earth's gravitomagnetism with accuracy of the order of 10 %. We first report the measurement of the Lense-Thirring effect, obtained in 2001 over nearly 8 years of data using the nodes of the LAGEOS satellites and the perigee of LAGEOS II: it fully agrees with the previous 1998 result over a period of 4 years only. Finally, we describe the 2004 determinations of Earth's frame-dragging, using the recently released Earth's gravity field models, generated by the space mission GRACE, and analyzing about 11 years of data of the nodes, only, of the LAGEOS satellites. This new analysis agrees with our previous measurements of the Lense–Thirring effect using the LAGEOS satellites and obtained with the JGM-3 and EGM96 Earth's models. However, this new determination is much more accurate and, especially, more robust than our previous measurements. Indeed, the present analysis uses the nodal rates of the two satellites only, making no use of the perigee rate, as in our previous analyses. By using the Earth model EIGEN-GRACE02S, we obtain a relative error of the order of 4 % to 8 % of the Lense-Thirring effect due to the uncertainties in the Earth static gravity field and a total root-sum-square error budget of about 5 % to 10 % due to all the error sources. Specifically, by using EIGEN-GRACE02S, we obtain: μ = 0.99 ± 0.1. This 2004 results fully confirm and improve our previous measurements of the Earth frame-dragging: the Lense-Thirring effect exists and its experimental value is within ~ 10 % of what is predicted by Einstein's theory of general relativity.
    <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>
    And no, I don't believe it necessary to E-Mail any of my champions, as from where I sit, the matter is already validated and accepted, but I might add that the only scientist on this forum I know of [physics, astronomy etc] is James. Sad that he chooses to ignore most of the real science threads.
     
  8. Q-reeus Valued Senior Member

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    Barking up the wrong tree here paddoboy. Can you point to anywhere this thread where I have attacked GR per se? No, you can't. I specifically limited criticism to the very widespread belief/characterization/interpretation of the dynamics of gravitational spin-orbit coupling between a central spinning mass and an orbiting test mass (spinning or not), as supposedly properly due to spacetime itself being variously twisted and/or dragged around like a whirlpool by the central spinning mass. It's nonsense and I explain clearly why it's nonsense particularly in posts as linked to that earlier thread.
    This is a forum where ideas are supposed to be freely exchanged. Challenging me to have to write up a paper fit for publication in some prestigious journal is silly.
    Instead try and deal with the substance of my specific critiques here, and if you can't then let it rest or actually email around for hoped for big-guns support of your mainstream all the way outlook.

    Any online search using my suggested words or similar comes up overwhelmingly with hits like 'proof spacetime is actually dragged around a spinning mass as predicted by Einstein' etc. etc. That characterization was simply wholly misleading from the start, should have been worded very differently, but unfortunately the original has stuck ever since. And I am being 'anti GR' for pointing out the oddity? Getting it right re gravitomagnetism not 'swirling spacetime' need have no impact on GR itself. Relax.
     
  9. paddoboy Valued Senior Member

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    Sure!...here....
     
    Last edited: Aug 6, 2020 at 9:59 AM
  10. paddoboy Valued Senior Member

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    Sure!...here....
    The Lense Thiring effect, along with BH's and gravitational radiation are all validated predictions of GR, and accepted by mainstream science, despite your comments to the contrary.
    Sure again, but as I stated, your anti GR record, claims and propaganda are dismissing Gr [or its predictions] as opposed to what mainstream accept. If you are so sure and confident that GR is that flimsy, and/or that frame dragging or gravitational waves are not supportive of GR, then yes, again, write up a paper for review.
    I've answered that, and nice change of pace by you there in referring to the experts as "big guns"as opposed to my champions. And of course mainstream is mainstream for a very good reason.
    Whether it has an impact or otherwise, is not of great concern. The facts are I have presented many papers in support and otherwise...that's science. And that includes the twisting of spacetime, or Lense Thirring effect asevidenced by GP-B.
    I mean we went through similar with gravitational radiation and your preferred option Vector gravity...did I get that right?
    And of course if and when something irrefutable and positive is raised by yourself, that is generally supported by mainstream, due to the evidence, then certainly, I will let it rest, as you put it.

    In the meantime I see no problem and it stands as is.
     
  11. Q-reeus Valued Senior Member

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    3,642
    ???? your follow on quote of me manifestly backs my claim - no attack there on GR proper.
    You continue to misinterpret my position thus attacking a straw man. The issue is whether Lense-Thirring is properly explained by 'twisting/whirling space/spacetime' (NO), or by the gravitomagnetic analog of Lorentz force well known in classical EM (YES). Not whether Lense-Thirring itself exists (it does). And I have made that perfectly clear all along. Bringing in BHs and GWs serves only to distract and conflate. Stick to your own OP topic - as I have done.
    See above, and earlier by me.
    Not much worth replying to there. Circularity sets in. Let's agree to disagree. No-one else here seems either capable of or interested in adding useful input. As expected.
     
  12. Xelasnave.1947 Valued Senior Member

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    Hi Q-reeus I hope you are safe and well.
    I am certainly interested but not skilled in GR in the least..however what I don't understand is I understand GR is a co ordinate system and basically geometry so when they say dragging or distorting space time is all they are saying is that the graph is getting distorted?
    Alex
     
  13. Q-reeus Valued Senior Member

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    Actually Alex as a tensor based theory GR is often said to be coordinate independent in essence, although coordinates are typically used to do specific calculations e.g. orbital mechanics of binary pulsars.
    But no when the oft repeated usual claim is made that 'the very fabric of spacetime is carried around by a spinning mass' etc. etc., it's not intended to mean distorted graphs or figurative hyperbole. In the earlier thread on this I gave a specific scenario making it obvious 'dragged space' was actually anti-relativistic as a concept.
    All very strange to me how the accepted lore became so entrenched.
    Read my #3 again.
     
  14. paddoboy Valued Senior Member

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