Einstein's predicted geodetic and frame-dragging effects, and the Schiff Equation for calculating them. Credit: Stanford University

Gravity Probe B Confirms Two of Einstein’s Space-Time Theories

Article Updated: 24 Dec , 2015

by

[/caption]

Researchers have confirmed two predictions of Albert Einstein’s general theory of relativity, concluding one of NASA’s longest-running projects. The Gravity Probe B experiment used four ultra-precise gyroscopes housed in an Earth-orbiting satellite to measure two aspects of Einstein’s theory about gravity. The first is the geodetic effect, or the warping of space and time around a gravitational body. The second is frame-dragging, which is the amount a spinning object pulls space and time with it as it rotates.

Gravity Probe-B determined both effects with unprecedented precision by pointing at a single star, IM Pegasi, while in a polar orbit around Earth. If gravity did not affect space and time, GP-B’s gyroscopes would point in the same direction forever while in orbit. But in confirmation of Einstein’s theories, the gyroscopes experienced measurable, minute changes in the direction of their spin, while Earth’s gravity pulled at them.

The project as been in the works for 52 years.

The findings are online in the journal Physical Review Letters.

Artist concept of Gravity Probe B orbiting the Earth to measure space-time, a four-dimensional description of the universe including height, width, length, and time. Image credit: NASA

“Imagine the Earth as if it were immersed in honey,”.said Francis Everitt, Gravity Probe-B principal investigator at Stanford University. “As the planet rotates, the honey around it would swirl, and it’s the same with space and time,” “GP-B confirmed two of the most profound predictions of Einstein’s universe, having far-reaching implications across astrophysics research. Likewise, the decades of technological innovation behind the mission will have a lasting legacy on Earth and in space.”

NASA began development of this project starting in the fall of 1963 with initial funding to develop a relativity gyroscope experiment. Subsequent decades of development led to groundbreaking technologies to control environmental disturbances on spacecraft, such as aerodynamic drag, magnetic fields and thermal variations. The mission’s star tracker and gyroscopes were the most precise ever designed and produced.

GP-B completed its data collection operations and was decommissioned in December 2010.

“The mission results will have a long-term impact on the work of theoretical physicists,” said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington. “Every future challenge to Einstein’s theories of general relativity will have to seek more precise measurements than the remarkable work GP-B accomplished.”

Innovations enabled by GP-B have been used in GPS technologies that allow airplanes to land unaided. Additional GP-B technologies were applied to NASA’s Cosmic Background Explorer mission, which accurately determined the universe’s background radiation. That measurement is the underpinning of the big-bang theory, and led to the Nobel Prize for NASA physicist John Mather.

The drag-free satellite concept pioneered by GP-B made a number of Earth-observing satellites possible, including NASA’s Gravity Recovery and Climate Experiment and the European Space Agency’s Gravity field and steady-state Ocean Circulation Explorer. These satellites provide the most precise measurements of the shape of the Earth, critical for precise navigation on land and sea, and understanding the relationship between ocean circulation and climate patterns.

GP-B also advanced the frontiers of knowledge and provided a practical training ground for 100 doctoral students and 15 master’s degree candidates at universities across the United States. More than 350 undergraduates and more than four dozen high school students also worked on the project with leading scientists and aerospace engineers from industry and government. One undergraduate student who worked on GP-B became the first female astronaut in space, Sally Ride. Another was Eric Cornell who won the Nobel Prize in Physics in 2001.

“GP-B adds to the knowledge base on relativity in important ways and its positive impact will be felt in the careers of students whose educations were enriched by the project,” said Ed Weiler, associate administrator for the Science Mission Directorate at NASA Headquarters.

Sources: NASA, Stanford University

, , , ,



67 Responses

  1. Olaf says:

    First!

  2. Lawrence B. Crowell says:

    Score another mile stone for big Al, Albert Einstein.

    LC

  3. Proof! I want Proof.
    A long-hand version of the data log of ALL the gyros please, in original paper form!

    (sorry…)

    • Torbjorn Larsson OM says:

      Anti-relativists will have their frame dragged into the science, relatively dissatisfied (read: kicking and screaming) all the time.

  4. Question says:

    the nature of frame-dragging and its effects is a fascinating area of study. as a “geometry guy”, it makes me feel like sketching things.

  5. Don Alexander says:

    This.
    Is.
    Fantastic.

  6. billy_stanley says:

    WOW! I hope I can get use to this understanding I have now. I am by no means a mathematician but astrophysics fascinates me. The fascination began when I read “A Brief History of Time.” I have read many books on the same subject but could never understand all the formulas most of the authors use. When it was spelled out to me I could imagine it in my mind. They say a picture is worth a thousand words. Well the two examples shown here speak upteen thousands of words. I can see what I could only imagine, and the accompanying text put it all in a nice little nut shell for me. Now let us visualize more than 10 dimensions.

  7. Greg says:

    It is reassuring to see these gravity principles confirmed yet again by another method. Unfortunately this measurement of the Lense-Thirring effect (which is what is new today regarding this experiment) was scooped by Tom Murphy in 2008 by the latest Lunar Laser Ranging experiments and with much greater precision (.1 percent versus 20 percent for this experiment.) The Lageos I and II satellite experiment also scooped this mission even earlier in 2004, achieving confirmation of frame dragging with 10 percent precision, although I believe the GPB data is still being refined to weed out noise which may still yield better precision. See references below.

    Murphy, T.W., Adelberger,E.G., Battat, J.B.R., Carey, L.N., Hoyle, C.D., LeBlanc, P., Michelsen, E.L., Nordtvedt, K., Orin, A.E., Strasburg, J.D., Stubbs, C.W., Swanson, H.E. & Williams, E., APOLLO: the Apache Point Observatory Lunar Laser-ranging Operation: Instrument Description and First Detections, Publications of the Astronomy Society of the Pacific, accepted, 2008. [arXiv:0710.0890]

    Ignazio Ciufolini, Dragging of inertial frames, Nature 449, 41-47 (6 September 2007) | doi:10.1038/nature06071

    • Torbjorn Larsson OM says:

      Thanks for the info, I remembered vaguely that frame dragging was already tested.

    • 1234567890 says:

      Sorry, Greg, but the results by Murphy et al. do not refer to the same effect tested by GP-B and LAGEOS. About the LAGEOS tests by Ciufolini, please note that after 15 years nobody has, actually, repeated them independently of Ciufolini himself. Moreover, the 10% accuracy in it is a legend. You may want to look at this recent open access
      L. Iorio, On Some Critical Issues of the LAGEOS-Based Tests of the Lense-Thirring Effect, Journal of Modern Physics, vol. 2, no. 4, pp. 210-218, 2011
      http://dx.doi.org/10.4236/jmp.2011.24029 and references therein. Enjoy!

      • Greg says:

        Very good reading indeed. This paper claims that Ciufolini’s analysis was biased by assigning fixed values to uncertain zonal harmonic values. When these uncertainties are factored in the accuracy decreases by 20 percent or more. There is a simple soultion, however, and that is having other laser range finding facilities repeat the experiment. I am puzzled why other teams have not done this yet. As it turns out all of the other papers done were done by various members of his team at his facility. This certainly sheds new light on the value of the GPB experiment.
        The actual effect measured by the laser range finders that scooped GPB is the gravitomagnetic effect. (conferring of rotation on a small object orbiting a massive rotating object) I had read a previous article studying relativistic jets of quasars which covers both the gravitomagnetic and Lense-Thirring effects which is probably what generated the confusion.

      • Torbjorn Larsson OM says:

        FTW Wikipedia do lists some earlier tests (though it may be this one and/or shaky et cetera). Anyway, the more tests the merrier!

  8. Valentina Tereshkova says:

    “One undergraduate student who worked on GP-B became the first female astronaut in space, Sally Ride.”

    So who am I? Chopped liver?

    • Uncle Fred says:

      Lol. It’s just Americans being Americans. Sometimes I think more than an Ocean separates them from the rest of humanity.

    • Billy says:

      You’re the first female cosmonaut in space.
      Sally’s the first female astronaut in space.

      🙂

  9. Valentina – (Whether it’s really you or not…)

    Thanks for a great laugh and appreciate the sense of humor –

    Respect!

  10. scozy says:

    this is facinating,
    but was wondering if this research will be backed up with an other project on a bigger scale ,like jupiter. If this data is correct; would the effects not be shown on a shorter time frame?

  11. interI0per says:

    The image of the sphere of the planet with a ‘well’ beneath the south pole is misleading.
    The “stress field” would project from the center of the sphere outward in an inverted ‘metasphere’ in all spherical directions. The stress decreasing with distance. The disc perpendicular to the equator (like Saturn’s ring disk) would be a projection of the maximum gravometric stress. This is caused by the maximum mass of the planet in the disc of the equator. (spin causes this)

    Also: I imagine space to be more like glass than honey.
    Does the ‘fabric of space’ possess inertia? It would seem to be massless but stressable.

    Would a hypothetically perfect spherical spinning mass impart coriolis to the surrounding volume of space?
    The gravity field of the Earth was recently shown to be far from spherical.

    • Torbjorn Larsson OM says:

      Well, it is an illustration. Spacetime creates inertia, is a better way of thinking of it I believe.

  12. Lawrence B. Crowell says:

    To give some idea of the physics behind this frame dragging a couple of points or aspects of looking at it can be made. This can be thought of as a form of magnetism associated with gravity, in much the same way magnetism is associated with the electric field and charge. This means that in analogy with electromagnetism a moving mass will be associated with a gravity analogue of a magnetic field. This means that a rotating mass will have a field similar to a magnetic field associated with a spinning charge. As a result the magnetic field for a spinning charge may be computed by the Faraday equation so that curl H = J, which if we integrate over a volume that contains the current density J

    int curl H dv = int H dv

    we then use the Stokes’ rule that this is equal to the magnetic flux H through the surface area bounding the volume

    int H da = int J dv

    Now let the volume be (4pi/3)r^3 and the area 4pi r^2 with spherical symmetry for ease of calculation and we get for constant current J and constant H

    H = 3J/r.

    Then for the current density due to the rotation of a charge density we now get an approximate formula

    H =~ 3Qw/r^3

    where w = the rotational frequency of the charge distribution and Q is the charge density. This formula is similar to the one for the Lense-Thirring effect

    From a more general relativistic approach the exact solution for this is from the Kerr metric. This is a rather complicated spacetime and tough to work in its exact form. However, an approximate version works pretty well, particularly if the gravity fields are very weak. To consider this we start with the idea of a metric, which is really just a form of the Pythogorean theorem. Given perpendicular coordinates ct, x, y, and z the distance from one’s coordinate origin to these points is

    s^2 = (ct)^2 – x^2 – y^2 – z^2,

    which has this funny sign difference with the spatial coordinates. For a spatial distance one just has d^2 = x^2 + y^2 + z^2, but for spacetime the distance is s^2 = (ct)^2 – d^2. If I divide through by the speed of light c then s/c is the time a clock measures along that distance. This is the invariant interval of time or proper time. We then write this according to an infinitesimal element of distance ds and with metric coefficients g_{tt}, g_{xx} and so forth

    ds^2 = g_{tt}(ct)^2 – g_{xx}x^2 – g_{yy}y^2 – g_{zz}z^2,

    where these metric elements for flat spacetime are just units (or one = 1), but for flat spacetime these may be complex functions.

    I will then write this for spacetime oriented at the equator of a rotating body. This means that g_{tt} = 1 – 2GM/rc^2, g_{rr} = 1/g_{tt} and there is a mixed coordinate element between the polar angle on the equatorial plane and time g_{t@} = J/Mc. Here @ means angle “theta” and J is the angular momentum of the rotating body. The metric is then

    ds^2 = g_{tt}(ct)^2 – g_{rr}dr^2 – 2g_{t@}cdtd@ – the rest

    The elements with g_{tt} have O(c^2) and the g_{t@} have O(c) contribution, which makes them the leading contribution. The g_{t@} = J/Mc is what will contribute to the frame dragging or Lense-Thirring effect

    This is then input into geodesic equation. To understand this requires some detailed knowledge of differential geometry and general relativity. So I will not delve into that in depth, but simply indicate what it gives. The radial form of the geodesic equation gives a differential equation

    d^2r/dt^2 ~ -GM/r^2 + (2J/Mc)d@/dt.

    The last term on the right is the “force” due to the gravi-magnetic field. The angular momentum is J = Iw, for I the moment of inertia of the Earth. I will leave the derivation at this point, for it requires a number of further steps However, it is worth noting that the angular momentum is in the z or azimuth direction, the velocity here d@/dt is in the angular direction. The cross product of these is in the radial direction which is the direction of the acceleration. This is then a veiled form of the Lorentz equation for the force on a charged particle moving in a magnetic field.

    LC

  13. interI0per says:

    HA! I was thinking the same thing as soon as i posted. (Perhaps it’s better to think of space with less viscosity than honey and not more (glass). Both space and the gravity that acts upon it must be abstracted in the mind to be contemplated. How best to do so?
    The magnetic field analogy is inaccurate in my mind (but close) for 2 reasons.
    I imagine gravity to be unipolar and static.
    Gravity would not emanate looping field lines but more of a gradually decreasing stress field around the mass in space.
    I think it’s utterly charge agnostic and the result of aggregations of neutrons.

  14. Andrew James says:

    “Imagine the Earth as if it were immersed in honey…”

    Good analogy, but honey is thixotropic and a sheer-thinning liquid, and whose viscosity thins when stressed through mixing. It is a non-Newtonian fluid, actually. Such fluids would not be analogous to frame-dragging precession. (Probably fairly esoteric point, but an important point.) Honey has a viscosity of about (η) 10 pa.s. (Pascals per second.) Less viscous materials are ordinarily in mPa.s (millipascals per second.) [American’s (I think) do not use to pascals use the term poise, being dyne second per square centimeter [dyne s/cm^2].]
    Lawrence’s text above seems similar to fluid dynamic viscosities, with the term “-GM/r^2” being equivalent shearing stress (Force / Accleration). The other term here is analogous to the velocity gradient,/I> for the rotating fluid.

    This would be instead be better compared to some like a ordinary newtonian fluid; perhaps like water or some simple aqueous solutions.

  15. Lawrence B. Crowell says:

    Strominger and his group have illustrated how the type I Petrov solutions to the Einstein field equations are equivalent to a set of solutions to the Navier-Stokes equation.

    http://arxiv.org/abs/1104.5502

    So the comparison between the structure of spacetime and hydrodynamics is fairly tight. The evolution of a spatial surface involves the flow of points on that manifold. It turns out that for a certain class of such solutions these are indeed isomorphic to a class of solutions to the Navier Stokes equations.

    LC

  16. The original purpose of the gravity B probe was to generally “prove” Einstein’s theory of General Relativity, After a great effort which involved high-cost funding and many years preparation which included many scientists and computations, the observations did not find that the calculations of General Relativity fit within the acceptable tolerances predetermined beforehand as necessary for proof of theory. Based upon results that did not fall within these predetermined tolerances, congress finally pulled the plug on this project funding in 2008.. To get the best data outcome possible and to salvage some value from the monumental costs and efforts, private funding was solicited to enable the finish of the project. The Saudi royal family paid for the last 3 year, wrap-it-up conclusions that we can now read.

    This is not the accurate conclusion that was hoped for when the experiment was originally proposed. Although there is strong evidence that a vortex model of gravity seems valid, and there are a number of such competing models, the predictions of General Relativity can only be considered to still be in the running since no other model seemed to predict things any better. There was no clear advantage of General Relativity over a few other competing models that also predict the same frame dragging effects.

    http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_

    • Andrew James says:

      “the observations did not find that the calculations of General Relativity fit within the acceptable tolerances & ” “….no other model seemed to predict things any better.”

      Let’s see General Relativity (off the top of my head….)
      – Gravity Probe A, 1976. Fly an atomic hydrogen maser on a Scout rocket launched to a height of 10,000 km. A maser is like a laser for microwaves. It produces microwaves of a very precise frequency. Measure the doppler shift due to gravity and motion and compare to predicted values (error = 70 ppm = 0.007%).
      – Confirmed in an experiment conducted in an elevator shaft at Harvard University by Robert Pound and Glen Rebka in 1959.
      – Clocks on planes experiment. October 1971. Four cesium beam clocks flown around the world on commercial jet flights during, once eastward and once westward, recorded directionally dependent time differences which are in good agreement with predictions of conventional relativity theory.
      Relative to the atomic time scale of the U.S. Naval Observatory, the flying clocks lost 59±10 nanoseconds during the eastward trip and gained 273±7 nanoseconds during the westward trip, where the errors are the corresponding standard deviations.

      How more accurate does it need to be? Have you any idea what a difficult problem this is to measure?

      “GP-B also advanced the frontiers of knowledge and provided a practical training ground for 100 doctoral students and 15 master’s degree candidates at universities across the United States. More than 350 undergraduates and more than four dozen high school students also worked on the project with leading scientists and aerospace engineers from industry and government.”… and one fool, who thinks some weirdo ad-hoc “vortex model of gravity” is a better explanation.
      Clearly you got your own degree from the back of a Corn Flakes packet!

    • Andrew James says:

      Hey, that is simply wacko!. Only a crazy person could say something as foolish as to what you’ve written above. What is clearly conclusive about this effect was that is was written about before it was discovered.
      I do strongly suggest you change your avatar name from forrest noble to forrest gump!

  17. According to the link that I posted above their accuracy/ error concerning frame dragging was within 19%, the stated goal was to be accurate within 1%. The geodetic effect was accurate to within .2% which reconfirmed prior findings of other studies.

    Those conducting the experiment/ probe believed the frame dragging variation between observation and theory were due to design and manufacturing errors of the probe rather than with the predictions of General Relativity.

    Below is a discussion of other gravity and torsion theories that were originally submitted for evaluation concerning gravity probe B’s data.

    http://prd.aps.org/abstract/PRD/v75/i12/e124016

    • Andrew James says:

      General Relativity has not been rejected by science because it has both good mathematical proof and excellent observational proof.
      The so-called Einstein–Cartan theory (what you are actually on about here), uses the idea of (affine) torsion. It is quite well-known to be a failed attempt to extend the geometric approach of general relativity to other areas of physics. Although Cartan proposed it in 1922, Einstein spent most of the last third of his career on theories that include torsion and he did not obtain any substantial result. Effects of torsion are, frankly, too small to measure empirically at this time. They (torsion theories) are rejected, because the effects are many times smaller in magnitude that what general relativity predicts.
      If it were to be proved, you would need instruments to measure to 0.1 micro arcseconds. The best we can do will be made by the Gaia astrometric satellite, and the will be several tens of micro arcseconds in precision. (and Gaia is yet to be launched!)
      Your Pan Theory, for what it is worth, is mostly untestable and is clearly wrong as observations in the real world do not match what it predicts. In the end, it is not the alternative theory that is wrong. It is the clear personal bias now favouring your incorrect concepts just because you don’t want to accept the solid predictions and observations made general relativity (for whatever reason.) Your bias has blinded you to look for fault when their is none.
      You state you Pan Theory is simpler, when the fact the opposite is true. It is more complicated because you need both general relativity and the Élie Cartan ideas of torsion. (He was also was not cosmologist or physicist. He was just a mathematician, who was hell-bent to promote his equivalence method and symmetric space theorems.)
      It is clear your motives are no pure, and that is the reason why few take you seriously. So, if you want to openly dis general relativity, you first have to understand it, then explain all of what it formally and successfully predicts. I see no need to toss everything out on the say so of just one somewhat dubiously educated individual.

      • Andrew James says:

        Let us see; be nice and polite….

        According to your own Pan Theory (and downloadable document) [linked through name here], you say;

        “Since General Relativity was unable to predict galactic stellar motions,” and
        “The fifth and most important characteristic of galaxies which is displayed by their stellar orbital speeds is the failure of General Relativity to predict stellar motion unless dark matter is progressively distributed from the outside of a galaxy inward, reminiscent of Ptolemy’s epicycles.”

        What? I don’t get it. Are stars moving a relativistic around the Milky Way? What have Ptolemy’s epicycles have to do with dark matter OR General Relativity?

        You say (pg. 57E1.1) ; “General Relativity equations have been shown to be quite accurate concerning the orbit of the planet Mercury.”
        and even worse is the statement;
        “Einstein’s equations of General Relativity (his theory of gravity) correctly predicted the small, non-elliptical variations in the orbit of Mercury that could not be predicted using Newton’s gravity equations. The difference between the two equations is small and only varies based upon a very strong gravitational force at a very close distance. Still, Einstein predicted this variance and Newton did not. These same equations are being used to predict the overall mechanics of galaxies and, indeed, the universe as a whole.

        No they don’t (text in bold). Where is General Relativity being used to calculate the ‘mechanics of galaxies’? (They are not moving very fast at all. I.e. 200 to 300 km.sec^-1)

        OK, then why not frame-draging precession of these satellites in Earth orbit?

        Again with this rather confused statement;
        “Gravity acts as a perpendicular vector of increasing increments as its linear vector and decreases up to the boundaries of gravitational equilibrium between stars where it acts solely as a small perpendicular vector which in general would act to maintain stellar distances, speeds, and positioning within galaxies as apposed to General Relativity and Keplerian type stellar motions which would form no observable patterns in a spiral galaxy’s form, contrary to what is observed in nearly all spiral galaxies.”

        What has general relativity got to do with spiral arms? I mean, they are moving only at 200-300 km.sec^-1, you know.

        Also; “The Pan-Gravity theory, contrary to General Relativity and the inclusion of dark matter (which is presently the standard gravitational model), asserts that gravity acts like a vortex in galactic and intergalactic space.”

        Where is the proof of this. I.e. Especially the mathematical proof?

        and “Gravity is not a purely radial or centripetal force. L. Although General Relativity might be considered a non-linear model of gravity like the Pan-Gravity theory, it predicts that gravitational attraction is primarily a radial force between objects caused by the warping of space, which is an invented concept.”

        Where is he proof of this? Are you not meaning angular momentum here?

        I don’t wish to be rude here , but this doesn’t make much sense me. I think your mistaking general relativity for the ordinary ‘run-of-the-mill’ Newtonian orbital motion (and problems of small accumulative effects like the three-body problem.) Do you really understand relativity or general relativity at all?

        Note: Finally I think you are really ripping-off basic ideas of “Einstein–Cartan theory” and are stating them as your own. It is the real origin of the torsion concepts you have been talking about here.

      • Torbjorn Larsson OM says:

        “Since General Relativity was unable to predict galactic stellar motions,” and
        “The fifth and most important characteristic of galaxies which is displayed by their stellar orbital speeds is the failure of General Relativity to predict stellar motion unless dark matter is progressively distributed from the outside of a galaxy inward, reminiscent of Ptolemy’s epicycles.”

        What? I don’t get it. Are stars moving a relativistic around the Milky Way? What have Ptolemy’s epicycles have to do with dark matter OR General Relativity?

        If I may…

        This is a folk science idea of “inductionism” as a valid theory of science as opposed to testing.

        It is a 19th century idea, I believe, rejected later but shored up by being a perfect instrument of inserting doubt (pseudoscience, postmodern philosophy) or gaps (fundamentalism, theology) where there are none.

        I prefer to take the option of Hitchens (?) here: “claims stated without evidence can be rejected without evidence” or something similar. Besides, arguably testing works.

      • Torbjorn Larsson OM says:

        Oops, too brief.

        What I mean is that the ref to epicycles is the mistake of saying that no theory is rejected since “one can save it by adding or modifying hypotheses”.

        Never mind that the original theory _was_ rejected, and we are now engaging with a new, hopefully improved, one.

      • Andrew James says:

        Thanks. I’ve just added this to my mental database.
        (I still don’t understand the motive here of Mr. Noble. It is kind of weird. Since he does not seem to want to elaborate. Perhaps he can’t.)

      • Andrew James says:

        Oh. I also should have said… In Wikipedia they say the following about Orbital decay under general relativity
        “According to general relativity, a binary system will emit gravitational waves, thereby losing energy. Due to this loss, the distance between the two orbiting bodies decreases, and so does their orbital period. Within the solar system or for ordinary double stars, the effect is too small to be observable.”
        [Gee. Wish I said that! I agree with this by the way…]

        Again this is just Newtonian orbital motion with the loss of angular momentum. Whilst it is true general relativity explains the apsidal (movement/ precession of the orbit nodes); in the majority of orbital systems general relativity / your pan theory / torsion are unnecessary to describe orbital motions. (Hence, the effects are not usually measurable or are minutely small.

        Note The Wiki article points out in the really extreme case, that the close binary system with pulsar, PSR1913+16, has an the observed orbital decay; being the time shift in seconds, tracked over three decades.

        From this we can only conclude Special Relativity is an adequate explanation for the motions of objects in gravitational systems. We add other things to the theory mix, or even replace adequate theory, when there is clearly nothing wrong? Sorry. I do simply fail to see what you are talking about or even if it is relevant. (unless I’m missing something or something you are not properly explaining.)

      • Lawrence B. Crowell says:

        The orbital decay of PSR1913+16 measured by Hulst and Taylor is an indirect indicator of gravity waves. As yet the direct detection of gravitational radiation has yet to be done.

        When ever I hear somebody say, “I have a theory,” my hair stands up a little bit. When it becomes clear that person has no substantial knowledge of physics I start looking for an escape or exit from the situation. Few physicsists spend endless years trying to work up some sort of conjecture they concoct as a “theory.” It takes little study to see how PAN theory being promoted by F. Noble is a load of nonsense. The problem of course is that this stuff emerges faster than it can be debunked.

        LC

      • Lawrence B. Crowell says:

        I have somewhat jaded opinions of popularizations of physics. Hawking, Davies, Kaku, and now Carroll have written them, and to be honest I think many people put down these books with wrong ideas about things. My brother, a molecular biologist, read Hawking’s Brief History of Time and ended up getting in his head a strange variation on the “theme” that was not entirely
        correct. Some people seem to step further and get some idea of how they have a solution to the problems these books may pose, which usually ends up with some errant idea that established physics is completely wrong. So these guys get some idea that E = mc, or E = mc^3 or… , and write up a crazy web page based on this. Then there are the electric universe pollywogs that have a sort of community of like minded error. This is stuff is often accompanied by these folks quoting a popularization.

        I’d rather see people get their F = ma stuff straight without any ideas about black holes, string theory or cosmology than to see this funny business that seems to be swelling up like a huge incoming tide. The internet in some ways makes things worse, where there are now whole communities devoted to this sort of silliness. It extends to biology, in particular with anti-evolution, and there is a vast universe of alt-health nonsense out there as well. There is even a curious community of folks who think Shakespeare was a fake.

        Who knows, in 25 years humanity may be utterly lost in its virtual reality and alt-reality matrix. Maybe this is a way that biology has of eliminating terminator species that threaten the whole web of life on this planet.

        LC

      • Andrew James says:

        I do kind of agree with you. The problem with this “theory” is that it has been hatched from something that this individual has read or misconstrued to be warped into some mishmash of ideas.
        I did read a lot of this document, not because I was particularly interested but I was looking for clues of the origin thence his distortion.
        Simply the guy seems to have completely wrong notions about relativity (This too applies to his notions of quantum mechanics, where he amazingly claims that his Pan Theory explains quantum mechanics , by his “paper” mention little about it (except pg.82). I.e. claiming “Quantum Theory, as apposed to Quantum Mechanics, is the underlying theory which tries to explain why Quantum Mechanics is valid, and attempts to provide its foundational logic. It is with this “logic” where the Pan Theory perspective finds fault, not in the mechanics of calculation.” Worst he doesn’t even seemingly know about quantum electrodynamics (QED) or quantum chromodynamics (QCD) — neither are mentioned.
        Whilst I do agree that the complexity of physics and cosmology and how the science is applied is confusing to most, it is this same complexity that drives people like F. Noble here to think… “Oh that is too hard”, it has to be simpler. Bingo! I have a better idea, and I better flog it to al and sundry.
        Sadly he doesn’t really understand why the planets orbit the sun or why binary stars orbit around their common centre of gravity. Somehow, god knows how, he has taken this, twisted it, and perceived it as some general relativity notion that is particularly obscure and ignores who swathes of simple celestial mechanics.
        As for the information of the 1920s “Einstein–Cartan theory”, i was just testing the guy out to see what he knew about it. (The notion of torsion or affine torsion has been possibly picked up by him in something he has read, but he doesn’t know of it implications. I think he sees its rejection as a fault in Einstein’s theory not as a fault in Cartan’s mathematical approach. He just says one thing but then talks about something quite different. It is the keywords you drop here and there, mixed with a little nonsense, and you can test their own limitations. I.e. The Einstein–Cartan theory has ben noted by him them expanded into his own cosmological doctrine.)
        In the end it is really personal theory, and against the UT rules, by these guys seem to be able to skirt the edges, be ambiguous, and get away with pretending they are talking on the subject at hand. Nancy has said to others we should ignore them completely, but the trap I dislike is they are after the ones who don’t know better, not the ones who can easily surgically dissect the flaws and analyse the origins of their own twisted logic.

        Note: I hear what you say. I do real appreciate your comments here, but I think if you are going to attack or ignore the nonsense, it is probably best to let one dissect the personal theory other than get caught in crossfire that helps them to avoid the necessary scrutiny. At least this can read text like this openly and maybe learn something important about accepting what others say or questioning the validity of the illegitimate statements and wrongs made. (It is hard work sometimes.)

        Cheers

        (I don’t think Mr Noble will return, though. Pity about that.)

      • IVAN3MAN_AT_LARGE says:

        The problem of course is that this stuff emerges faster than it can be debunked.

        Yeah, it’s the same with shaving: if you don’t shave regularly, you end up looking like a bum!

      • Torbjorn Larsson OM says:

        Ditto on the popularizations. They do let people speculate a bit over the boundary of what we have observations to match. Nothing wrong in that, except that they don’t realize it _is_ speculation.

  18. Andrew James says:

    I believe it will eventually be realized that both the Big Bang model and General Relativity are perfectly correct theory. That’s why Inflation is needed, dark matter, dark energy, general cosmology, etc. The answer I believe we already know is profoundly simple, as are our current theories. Ideas like the Pan Theory is simply incorrect theory because they are too contrived to be true.

  19. Lawrence B. Crowell says:

    @ Forest Noble: Nothing proves general relativity, for the reason that science is not about proving theories. Theories make predictions about what is observed in nature and if measurements and observations substantiate these predictions the theory is supported. This does not prove a theory to be true in a mathematical sense. Theories can be proven to be false. Observations or measurements of something other than what the theory predicts falsified that theory. Even if that theory is supported by a vast body of prior evidence, this will indicate how the theory fails outside some domain of observation. This happened to Newtonian mechanics, where it fails when the domain of experience is very small near the atomic scale or it involves velocities close to the speed of light and with large gravity fields.

    General relativity has yet to pass one major test, which is the detection of gravity waves. So far general relativity has passed each test quite spectacularly. The detection of gravity waves will give a decent support for the main physical interpretation of general relativity. Inflationary cosmology is due to the existence of a large vacuum zero point energy that contributes a huge energy density for a de Sitter spacetime. Some residue of this vacuum still exists and is what we label as dark energy. In both cases the spatial manifold on the Hubble frame exponentially expands. During the early inflationary period this expansion was huge, but now it is enormous. A precise understanding of this requires that we know all the quantum states of the universe, which is something I spend considerable time musing over.

    LC

  20. @Lawrence B. Crowell,

    You are correct concerning “proof of theory.” This is an expression that probably should not be used.

    As far as gravity waves are concerned, I do not understand why they are needed for General Relativity or the BB model since according to nearly all interpretations of GR matter “warps space” surrounding it which as I understand it is the reason for gravity so I do not understand why gravity waves are needed for either model? — or even why it is thought by many to be a prediction of the theory.

  21. Lawrence B. Crowell says:

    Gravity waves come about when arrangements of gravitating bodies, which are as you say warping space, are in motion. The causality principle states that an influence traverses an interval at the speed of light or less. So if these gravitating bodies are in a certain dynamical configuration the information about how that “warping” evolves reaches the distant hinterlands away from this system in a causal manner. These are gravitational waves. It is similar to the change in a configuration of charged particles, where the electric field lines adjust themselves away from this system in an electromagnetic wave.

    Now do not go running off thinking you actually understand what gravitational radiation is. There is a lot more here, and a deep understanding requires an understanding of the Petrov-Penrose-Pirani solutions based on eigen-Killing vectors of the Weyl curvature. A gravity wave is a situation where without any source in vacuum there is a change in the Weyl curvature as measured by observers on various geodesics.

    LC

  22. @ Andrew James,

    Thanks for the civil demeanor of your last postings.

    That matter creates “gravity waves” may be a very valid idea but what impact would gravity waves have in cosmology if they were not the cause of gravity but just an effect? even though a Nobel Prize was given for the “discovery” of gravity waves.

    This thread is about gravity Probe B and its impressive achievements so I don’t wish to discuss my own ideas but the reason why I say in my book that the Pan Theory is a simpler and more logical model is because dark matter, dark energy, Inflation, the expansion of the universe, no extra dimensions, etc. etc. are not needed for this model — whereby I provide observational data in some cases showing that this model (my own mathematical formulations) better match observed reality than mainstream formulations: GR and the Hubble Formula.

    As to the clarity of my postings, I have a book editor for the wording of my book/ theories but none for these postings 🙂

    • Olaf says:

      That Pan Theory sounds more logical, does not automatically mean that it is based in reality it could still be fiction.

    • Andrew James says:

      Sorry, gravity waves are not being discussed here. It is about General Relativity and the proof by the Gravity B probe of frame-dragging precession.

      Also very nice way of avoiding scrutiny by saying “This thread is about gravity Probe B and its impressive achievements so I don’t wish to discuss my own ideas.” ; but this particular discussion just happens to be what Gravity B is investigating and your assertion that what it found does not support General Relativity. We are not talking of your wrong Pan Theory, we are talking of aspects of it relating to General Relativity.
      Your assertions in your on-line personal theory “book” clearly shows you lack the necessary understanding of relativity. If you cannot substantiate your earlier claims that General Relativity is somehow wrong, the you should retract your incorrect statements. The only reality here is your views are mostly wrong and misguided.

    • Torbjorn Larsson OM says:

      “dark matter, dark energy, Inflation, the expansion of the universe,” The three first _are_ needed in standard cosmology, the later is a simple observation (that is predicted from standard cosmology).

      It is simply wrong to say that parsimony can overrule theory (i.e. the use of prediction from observation).

    • Torbjorn Larsson OM says:

      By the way in this context, dark energy doesn’t need the direct expansion of the universe to be tested anymore. It is observed by its effect on CMB alone:

      “For the first time, measurements of the cosmic microwave background radiation (CMB) alone favor cosmologies with w = -1 dark energy over models without dark energy at a 3.2-sigma level. We demonstrate this by combining the CMB lensing deflection power spectrum from the Atacama Cosmology Telescope with temperature and polarization power spectra from the Wilkinson Microwave Anisotropy Probe. The lensing data break the geometric degeneracy of different cosmological models with similar CMB temperature power spectra.

      Our CMB-only measurement of the dark energy density Omega_Lambda confirms other measurements from supernovae, galaxy clusters and baryon acoustic oscillations, and demonstrates the power of CMB lensing as a new cosmological tool.”

      I.e. CMB spectra + gravity lensing of CMB provides evidence for DE. Also note that the CMB first dipole is a much better fit with DE, fig 1!

  23. interI0per says:

    Let’s just call it idle speculation eh?

    Would the incoming photons from the guide star be deflected in the ‘gravity well’ too?
    I would say so.. it is after all the very effect they are looking for.

    • Lawrence B. Crowell says:

      The gravity Probe B integrates the deviation over a long time. Each photon has a tiny deviation over a very short period. This ends up being a very small error.

      LC

  24. Andrew James says:

    I’ve just read an excellent Sky and Telescope on-line article of this “Gravity Probe B: Relatively Important?” by Shweta Krishnan. This gives another different slant on this UT story. See http://www.skyandtelescope.com/community/skyblog/newsblog/121390204.html

    (This is one of the best general astronomical related articles about astronomy and astrophysics I’ve read for some time. It is detailed and place the story in its historical context. Bravo!)

  25. @Olaf,

    “That Pan Theory sounds more logical, does not automatically mean that it is based in reality it could still be fiction.”

    Your quote above is certainly true, but I think this theory is arguably equally or better supported by observation than the BB model which also may be just fiction. The determining factor for any model should be predictions that match observations with few unpredicted surprises such as those observations that led to changes of theory that necessitated Inflation, dark matter, and dark energy.

    This model needs none of these add-on hypothesis to explain what is being observed.

    • Andrew James says:

      Observation. Flexing ego (or pretending in your own fictions) does not improve hypothesis or theories either. If what you say is true, then the non-existent followers of your own personal theory do not accept your assertions. No ground base of support means something equally as important; your’s is a bigger fiction than the one you wish to supplant.
      Predictions here is you are just wasting your’s and everyone else time; and when you realise it, you will not be able to bear the disappointment. I just hope you wake up to your folly before it is all too late.

  26. “…….but this particular discussion just happens to be what Gravity B is investigating and your assertion that what it found does not support General Relativity”

    I made no assertion concerning Gravity Probe B or General Relativity, only that the accuracy findings of frame dragging were within an accuracy of 19% (I posted a link) and not the 1% accuracy that they hoped for. I too think the error was probably related to the equipment or the design of the experiment rather than the theory. The mathematical variations of the Pan Theory to GR do not become readily apparent until after maybe 2 light years distance so I cannot presently (or maybe never) dispute GR at distances less than this distance such as the Earth’s “frame dragging” effect and the experimental results of Gravity Probe B.

    This variation between these gravitational models is best observed, measured, and compared at galactic scales which is unrelated to Gravity Probe B.

    • Andrew James says:

      Sorry. Much of what you say here is very silly, and what is said, is really meant to confuse or just avoid scrutiny. If you cannot or will not answer basic questions and are unwilling to be confronted in what you have already said, there is no point saying anything more.
      One thing we can truly assert. Your own fantasy placed in your so-called Pan Theory is not fooling me or anyone.
      A cosmologist you clearly are not. 🙁

  27. Lawrence B. Crowell says:

    The evidence for the big bang is pretty conclusive. First there is the Hubble expansion result that the velocity of a galaxy is related to its distance d a constant H = 75km/sec/Mpc, v = Hd. This applies locally,and for much greater distances there is a deviation from this. The other is the abundance of deuterium and helium in the universe, which is predicted by the thermodynamic conditions of the early universe. The other is the CMB due to the end of the radiation dominated period, and the flatness of the universe is evidence for inflationary big bang. The big bang has emerged as a very substantial part of the scientific canon of knowledge.

    LC

    • Andrew James says:

      You said; “Although there is strong evidence that a vortex model of gravity seems valid, and there are a number of such competing models, the predictions of General Relativity can only be considered to still be in the running since no other model seemed to predict things any better. There was no clear advantage of General Relativity over a few other competing models that also predict the same frame dragging effects.”

      This is wrong. Your own document, with quotes from it, shows this is statement is wrong. General Relativity has passed every test to date with flying colours. You state this to validate you own view, and not to examine the implications of the support for general relativity by science, physics and cosmology. Your own bias ignores the fact of the possibility that Gravity B’s instrumentation might be faulty or some unknown error has occurred.

      To quote the independent S&T link earlier; “The truth is, we did. The LAGEOS satellites, lunar ranging, the Cassini mission’s radio experiment, and binary pulsars, to name just a few, have all verified general relativity — including these two particular predictions — sometimes to much higher accuracy than Gravity Probe B.”

      Your statement (above) simply says your assertion is wrong and false; also verifying your Pan Theory rejection of General Relativity is unsubstantiated.

      End of line.

  28. Your quote: “Your own bias ignores the fact of the possibility that Gravity B’s instrumentation might be faulty or some unknown error has occurred.”

    I think you did not read this statement of mine above.

    ‘I too think the error was probably related to the equipment or the design of the experiment rather than the theory” (General Relativity), at least within the scope of this experiment,

    • Andrew James says:

      Nice try, but I read it perfectly well, and I expected such a response..

      The problem you now have is that you cannot ignore use that excuse to deny your even earlier statement (which is also false, and now openly shows you have just contradicted yourself); I.e. “The original purpose of the gravity B probe was to generally “prove” Einstein’s theory of General Relativity, After a great effort which involved high-cost funding and many years preparation which included many scientists and computations, the observations did not find that the calculations of General Relativity fit within the acceptable tolerances predetermined beforehand as necessary for proof of theory.”
      This again does not mean General Relativity is wrong nor that “…the observations did not find that the calculations of General Relativity fit within the acceptable tolerances predetermined beforehand as necessary for proof of theory.” (Your words.)

      Either way you look at it, you cannot conclude (like your Pan Theory or your own statements here) that; “There was no clear advantage of General Relativity over a few other competing models that also predict the same frame dragging effects.”

      Again your clearly bias opinion is not substantiated that General Relativity is unproven and is logically reaffirmed. I.e. You don’t really believe the instrumentation was at fault, otherwise you would not be stating; “There was no clear advantage of General Relativity over a few other competing models that also predict the same frame dragging effects.” Why is that?

  29. My quote: “There was no clear advantage of General Relativity over a few other competing models that also predict the same frame dragging effects.”

    Your question: “Why is that?”

    My quote above was my opinion concerning the Gravity B Probe experiment relating to the frame dragging measurement results within a 19% error factor, concerning the predictions of GR.. And as I said the error I believe was probably with the experiment or equipment since accordingly such a wide variance has not showed up in other related experiments.

    • Torbjorn Larsson OM says:

      So you do accept the experiments at large, and that the GB Probe was correct after successfully having some large systematic effects taken into consideration. Then why argue that it didn’t test GR, when it is obvious to everyone that it did?

    • Andrew James says:

      …and, of course, general relativity was proven to be perfectly correct, yet again.

      So why believe in another theory? All other models are both unnecessary and unsubstantiated (including you own.)

      Why doubt, when there is no need to doubt!

  30. As I said before, I think the divergence of Gravity Probe B measurements from GR predictions was likely due to errors of the experiment or the equipment. The primary reason for my conclusion is that observations were not consistent with themselves and diverged greatly from the expected quantities before they narrowed down the error divergence range to “within 19%” of the predicted value.

    This being said, I would not be surprised if the fault was instead or also with GR or the interpretation of it concerning the frame dragging effect.

    This has also been discussed by others concerning Gravity Probe B before it was launched or made any measurements.

    http://eands.caltech.edu/articles/LXV3/gravity.html

    Quote from link above

    Testing history

    Gravity Probe B is intended to measure the frame-dragging effect to an accuracy of 0.3 percent, and will be the first direct measurement of the effect and of its magnitude. While many scientists feel confident that the results from Gravity Probe B will simply confirm Einstein’s predictions, there are those who expect that the answer will be something quite different. As Nobel laureate Chen Ning Yang put it: “Einstein’s General Relativity theory, though profoundly beautiful, is likely to be amended . . . The Stanford experiment is especially interesting in that it focuses on the spin. I would not be surprised at all if it gives a result in disagreement with Einstein’s theory.”

    • Andrew James says:

      Self-validation for the sake of ego or being heard is so ridiculous.
      Saying “amended”, doesn’t mean your saying; “There was no clear advantage of General Relativity over a few other competing models that also predict the same frame dragging effects.”

      Yang was talking about the geodetic effect, and as far as anyone knows, it precessional movement is also predicted by General Relativity. It’s effect on the Earth and Moon’s motion. It is NOT the measure of the frame dragging effect. Gravity Probe B found the geodetic effect was verified to a precision of better than 0.5% percent , as announced on 14th April 2007.
      In this case Yang was talking about the geodetic effect. Possible variations are thought to be from Thomas Precession, which is a kinematic effect as seen in gyroscopes spinning velocity. This effect is actually occurs in the flat spacetime under Special Relativity. The calculation of the effect is notoriously difficult in multiple inertial frames.
      The problem is knowing all the effects within the solar system bodies that have effects on the correct frame dragging effect of the Earth.

      You will find (again) the error is not that of General Relativity but of other similar effects that effect the final result. Yang is talking about this not you rather doltish ideas that General Relativity is wrong or incorrect.

      So as per usual you use half-truths and distortions to validate your wrong cosmological conclusion. No one is fooled by what you say. (Yet again). Again it puts you at odds with the physics community who know far more and much better than you; leaving you clearly beyond your depth.
      Nice try though, but sadly, no cigar…

    • Andrew James says:

      Note: You’re going to have to do much better than this to win this argument.

  31. Anonymous says:

    Is frame-dragging created by a form of friction? The explanations online do not really seem to address the underlying physics understandable to the lay-person.

  32. Torbjörn Larsson says:

    It _is_ general relativity, so I’m not too certain of the physics which I haven’t studied at that level of theory. However:

    No, it isn’t the phenomena of friction, since that acts between bodies in contact. It is a phenomena of general relativity, which acts between bodies and the spacetime they are in.

    For reasons that are too long to start the description with, relativity predicts that clocks ticks with relative differential rates.* Clocks that are moving free in space ticks the fastest. So we want to keep track of “free space”, which is the reference to go to.

    Around a rotating mass, the spacetime volume that best approaches free space in character is dragged around the mass in the direction of rotation. Free space is called “an inertial frame” in relativity, so this is “frame dragging”.

    The way it comes out in practice with the effect of frame dragging and its effect on other masses close to the rotating mass is an added precession of gyroscopes.

    Does that help?

    * This has to happen to keep physical laws the same everywhere in free space, which is what is expected and observed. But the way it happens becomes a bit … involved.

Comments are closed.