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Space probe confirms general relativity

gyro.jpg“We’ve tested Einstein’s universe, and Einstein survives,” said principal investigator Francis Everitt, at a press conference at NASA today to release the final results from Gravity Probe B, a spacecraft launched in 2004 to test predictions of Albert Einstein’s theory of gravitation. The new results, accepted for publication in Physical Review Letters, include a much-anticipated confirmation of frame-dragging, an effect in which the rotation of the Earth twists its gravitational field, causing gyroscopes orbiting in the field to wobble.

Gravity Probe B flew from 2004 until 2005, but unexpected electrostatic effects detected in its final 46 days of operation produced a systematic error that swamped the scale of the frame-dragging effect, and it has taken six years of data analysis to unpick that. In the end, the precision of the frame-dragging measurement is reported as 20%, which is several times what the mission had promised, and half the precision of an earlier frame-dragging confirmation claim by Ignazio Ciufolini at the University of Salento in Lecce, Italy and Erricos Pavlis of the University of Maryland in Baltimore, who reported measurements of the precession of the orbit of the LAGEOS (Laser Geodynamics Satellites) that flew in 1976 and 1992. Ciufolini congratulates the Gravity Probe B team, “GP-B was a beautiful and challenging experiment,” he says. But he questions the level of confidence that it’s possible to have in their 20% result, given that the systematic error they had to reckon with was around 15 times the size of the effect they measured.

The NASA press conference highlighted the technological achievements of Gravity Probe B, which included the creation of the roundest spheres ever manufactured (pictured) to serve as the four gyroscopes whose precession was measured. In the five decades it took for Gravity Probe B to be conceived, developed, launched, and its data analyzed, Everitt said, 100 PhDs worked on the project and more than 353 undergraduates.

Comments

  1. Report this comment

    Bruna Romano said:

    It is incorrect arguing that the uncertainty in the LAGEOS tests is 10%. Several peer-reviewed papers demonstrated that it is likely much larger because of several sources of systematics. LARES will not reach 1%, as demonstrated in peer-review literatue. It also incorrect claiming that independent US and German teams confirmed the LAGEOS tests: no published papers in peer-reviewed journals by such teams actually exist in literature.

  2. Report this comment

    Bruna Romano said:

    Technically speaking, frame-dragging was ever neither explicitly modeled nor estimated in LAGEOS data analyses. It was not even estimated in the global gravity field solutions by several international teams.

    Its existence was likely inferred from what one apriori hoped to be found in real data. After more than 15 years the situation did not change.

  3. Report this comment

    Uncle Al said:

    Didn’t Bill Fairbank, also at Stanford, smooth cryogenic patch potentials with a couple of hundred nm of copper deposition, as in Rev. Mod. Phys. 64 237 (1992)?

  4. Report this comment

    Zilli_000 said:

    Yes, I agree with Romano.

    In literature I’ve found those papers. This invited review by several authors in Astrophysics and Space Science, vol. 331, no. 2, pp. 351-395, 2011.

    This recent paper in

    General Relativity and Gravitation, vol. 43, no. 6, pp.1697-1706, 2011. They deal with LARES as well. And this one, which is open access: Journal of Modern Physics, vol. 2, no. 4, pp. 210-218, 2011. All in all, GP-B is likely still better than LAGEOS (LARES will not be an improvement), although it was certainly a delusion with respect to the expectations.

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    Anadish Kumar Pal said:

    It’s strange. General relativity cannot explain the gyroscopic effect itself, while gyroscopes are used to test its postulations. Let alone inertia and momentum. Why can’t it explain the gyroscopic effect itself? Because it has set for itself the impossible stumbling block of the speed of light in vacuum to be a constant. Relativity is willing to change everything else but this. Hence the tying in knots when it tries to reconcile itself to quantum mechanics.

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    tttito said:

    Well, in 2008 NASA’s Senior Review Committee wrote that “the gap between the current error level and that which is required for a rigorous test of a deviation from GR is so large that any effect ultimately detected by this experiment will have to overcome considerable (and in our opinion, well justified) skepticism in the scientific community.” That the experiment was basically flawed was clear already in 2004, when the satellite reportedly “warped into hyperspace” (sic) indicating a major design flaw.

    PS Relevant links/references on my blog.

  7. Report this comment

    Robin said:

    “Bruna Romano" is NOT WELL INFORMED,, indeed:

    The German GFZ results have been published, jointly with the Universities of Maryland and Salento in:

    (a) Recent Results from SLR Experiments in Fundamental Physics, Proc. 15th International Workshop on Laser Ranging, Canberra, Australia, October 15-20, 2006.

    and together with the results by the University of Texas at Austin, JPL Caltech (J. Ries and his team), the Univ. of Rome and the above mentioned Universities in:

    (b) Space Science Reviews, 148, 71-104 (2009).

    © General Relativity and John Archibald Wheeler, (Springer, 2010), p. 371-434

    (d) General Relativity and John Archibald Wheeler, (Springer, 2010), p. 467-492

    and they have been accepted for publication and are just going to appear in:

    (e) EPJ Plus (2011).

    The independent results by the University of Texas at Austin, JPL Caltech (J. Ries and his team) have been presented at invited talks at:

    (A) J.C. Ries, R.J. Eanes, M.M. Watkins, Confirming the frame-dragging effect with satellite laser ranging, in: 16th International Workshop on Laser Ranging, Poznan, Poland, 13–17 October 2008

    and

    (B) International Astronomical Union Symposium 261, Relativity in Fundamental Astronomy, Virginia Beach, VA, USA, 27 April-1 May 2009.:

    ON THE OTHER HAND, WE ARE WONDERING, AS ANY SCIENTIST SHOULD DO, IF ANY OTHER TEAMS. REALLY INDEPENDENT BY THE GP-B TEAM, WILL EVER BE ABLE TO REPEAT THEIR DATA ANALYSIS AND THUS, STARTING WITH DIFFERENT HYPOTHESES (see the comment by Gabby) ON THE NATURE OF THE SYSTEMATIC ERRORS, WOULD

    EVER BE ABLE TO FIND THEIR SAME RESULTS!

  8. Report this comment

    Robin said:

    About the “peer-reviewed papers” mentioned by “Bruna Romano”, all by Iorio and co., we found, among others, a number of replies to these in:

    New Astronomy, 10, 636-651, 2005, New Astronomy, 11, 527-550, 2006, Space Science Reviews, 148, 71-104 (2009), “General Relativity and John Archibald Wheeler”, Springer 2010, with two papers, one on LAGEOS p. 371-434 and one on LARES p. 467-492, and we are sure other papers are soon going to published.

    The results of the LAGEOS+GRACE measurements have been published in Nature (Letters), 431, 958-960 (2004), Nature (Review), 449, 41-47 (2007) and also in the above papers.

    If three independent teams independently infer, with independent software, the same measurement with the same error budget and then they decide to publish these results in a joint paper, aren’t these still three independently obtained measurements? Or perhaps there is a conspiracy among these research centers:

    University of Salento, University of Maryland Baltimore County, Sapienza University of Rome, GeoForschungsZentrum-DLR Potsdam, Center for Space Research and Center for Relativity of the University of Texas at Austin, JPL-Caltech: this must have been a huge conspiracy to agree with the same results!!! But to us it seems difficult to be possible!

    By the way the GP-B results are to our knowledge been obtained only by the GP-B team, but the LAGEOS results have been obtained and published by people working at, at least, 7 international universities and centers (above).

    On the other hand, it is interesting that there are a number of papers raising doubts on the GP-B results. See, e.g., the papers by O’Connell; starting with his Nature paper The gyroscope test of relativity, B. M. BARKER, R. F. O’CONNELL, Nature 312, 314-314 (22 November 1984) doi:10.1038/312314b0, predicting the failure of GP-B, and also the more recent paper: “Gravito-Magnetism in one-body and two-body systems: Theory and Experiment,” in “Atom Optics and Space Physics,” Proc. of Course CLXVIII of the International School of Physics “Enrico Fermi”, Varenna, Italy, 2007 (IOS, Amsterdam, 2009). We are sure that soon several other papers will be published about the “strange” reduction of the GP-B systematic errors from 300 % to 19 %, i.e., with an elimination of a factor of about 94 % in the systematic errors plaguing the GP-B experiment: this certainly is a record detained by GP-B.

    On the ArXiv we also found the following papert:

    http://xxx.lanl.gov/pdf/0712.3934v1

    It is very interesting, no matter if this Forst is an artistic pseudonym, as probably is, or not, you should read it!

    Finally, even if Iorio would be right in his 30 % error budget (and he is not, indeed in the various papers above mentioned is shown that the error budget is 10 %) this frame-dragging measurement was obtained at essentially no cost (the data were already available at NASA for geodetic purposes) whereas the 19 % result of GP-B, even if one would accept it as a solid result, has been obtained by spending at least 760 M$ !

  9. Report this comment

    Bruna Romano said:

    Robin, alias Nightmare in the Science blog on this same topic, is getting very nervous and insecure, as it turns out from his tone. Indeed, he write “peer-reviewed” papers about Iorio’s works: why? They are, indeed, peer-reviewed papers, not “peer-reviewed” papers. It is one of the usual tactics and tricks used by Robin-Nightmare since long time to painfuly try to discredit Iorio, having not rational and scientific arguments. On the contrary, the works by others he is trying to sell us are just conference talks, slides and proceedings. Or book chapters of a book edited by Ciufolini himself. Or one (1) paper going published in a journal (EPJ Plus) with Ciufolini himself as editor: it is likely that Ciufolini himself will be one author, if not the first author. And Ciufolini is always the first author (second in one case in which Pavlis is the first one) of all such alleged “independent” tests. Robin-Nightmare trusts the “paper” by Forst (You may want to read what the ArXiv moderators wrote.) withdrawn by ArXiv moderators: he is the only person worldwide, apart from Ciufolini himself. Anyway, I feel really incredible that one wants to make an independent test of an effect, and….goes to publish as second, third, etc. author of papers written by the very same author with respect to whom he should be independent! Of course, I would attempt to publish a research paper in some peer-reviewed international journal without myself in the editorial board, and without my competitor as first author! Please, notice also that those institutions are by no means officially involved in the LAGEOS tests which are, indeed, completely absent from their researches. They are just individual initiatives. Nothing bad in that, of course, but it is misleading and deceptively pompous to induce people to believe that such tests are official activities of such a joint consortium. If such tests were really so important, well estabilished, rooted and accepted as they stand, why they are not adequately publicized by all such institutions as some of their most prominent activities? If Iorio’s works were so irrelevant and ininfluent, why they are continuosuly getting published and why Robin-Nightmare desperately continues to fight against them with all means, trying to cancel them, remove them, discrediting their author and so on? But, again, nothing new: it’s just the same old tactic of Robin-Nightmare in search of endorsements and credibility.

  10. Report this comment

    newsfor general said:

    “We’ve tested Einstein’s universe, and Einstein survives,” said principal investigator …


    Mary

  11. Report this comment

    News for genaral said:

    Please give more information.

    ————

    gayathri

  12. Report this comment

    Lorenzo Iorio said:

    The Arxiv moderators, in their comment to the submission arXiv:0712.3934 [gr-qc] by G. Forst, reported a case of scientific misconduct by Ignazio Ciufolini, author of the competing tests with LAGEOS. They write: ‘‘This submission has been removed because ‘G.Forst’ is a pseudonym of Ignazio Ciufolini, who repeatedly submits inappropriate articles under pseudonyms. This is in explicit violation of arXiv policies.’‘ On 9 May 2011, user Robin posted on this blog the following comment on the paper by G. Forst: ‘’ It is very interesting, no matter if this Forst is an artistic pseudonym, as probably is, or not, you should read it! ‘’

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    Arif BK Seo said:

    Please, notice also that those institutions are by no means officially involved in the LAGEOS tests which are, indeed, completely absent from their researches. They are just individual initiatives. Nothing bad in that, of course, but it is misleading and deceptively pompous to induce people to believe that such tests are official activities of such a joint consortium. If such tests were really so important, well estabilished, rooted and accepted as they stand, why they are not adequately publicized by all such institutions as some of their most prominent activities? If Iorio’s works were so irrelevant and ininfluent, why they are continuosuly getting published and why Robin-Nightmare desperately continues to fight against them with all means, trying to cancel them, remove them, discrediting their author and so on? But, again, nothing new: it’s just the same old tactic of Robin-Nightmare in search of endorsements and credibility.

  14. Report this comment

    Lorenzo Iorio said:

    And now, the latest news from ArXiv!
    After having written to me today that they put their comment in the form I quoted in my previous post in September 2013, they also wrote to me that both their original comment (the one in which, in early 2008, they wrote that Forst was an Italian physicist unwilling to reveal his identity, and adding a link to the Mr. Ciufolini’s 2007 paper in Nature) and their modified one (the one of September 2013 in which they explicitly mentioned Mr. Ciufolini) are now against their current policies!! So, they have now censored all!!

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      Lorenzo Iorio said:

      Note that ArXiv moderators did not censored their own comments because of possible errors about the real identity of G. Forst, but because of an alleged, sudden change of their own policies. Unfortunately, there is no trace at all of such “changes” in their policy, which do not treat at all cases like this

      https://www.academia.edu/5492205/Reply_by_ArXiv_moderators_to_an_inquiry_of_mine_where_they_asserts_to_have_suddenly_changed_their_policies_since_5_years_and_4_months_respectively_they_kept_unaltered_their_original_and_modified_retraction_comments_on_the_pseudonym_used_by_Ciufolini

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        Lorenzo Iorio said:

        Again from ArXiv: now, they have fully reinstated their September 2013 comment explicitly exposing Mr. Ciufolini. Let’s wait and see for the next episode…

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    Lorenzo Iorio said:

    CLAMOROUS! Mr. Ciufolini strikes back! Now, he is…..GIANNI FELICI, from Milan!!

    http://arxiv.org/abs/gr-qc/0703020

    Now, ArXiv moderators write: “ This submission has been made by G. Felici, a pseudonym of Ignazio Ciufolini, who repeatedly submits inappropriate articles under pseudonyms, in violation of arXiv policies “

  16. Report this comment

    Lorenzo Iorio said:

    UPDATE! Today, ArXiv moderators have again censored both their comments exposing Mr. Ciufolini as author of the pseudonyms “G. Forst” and “G. Felici”.

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