{"id":1215,"date":"2006-03-24T18:18:04","date_gmt":"2006-03-25T01:18:04","guid":{"rendered":"http:\/\/dabacon.org\/pontiff\/?p=1215"},"modified":"2006-03-24T18:18:04","modified_gmt":"2006-03-25T01:18:04","slug":"gravitomagnetic-london-moment","status":"publish","type":"post","link":"https:\/\/dabacon.org\/pontiff\/2006\/03\/24\/gravitomagnetic-london-moment\/","title":{"rendered":"Gravitomagnetic London Moment?"},"content":{"rendered":"

Two papers (experiment: gr-qc\/0603033<\/a>, theory: gr-qc\/0603032<\/a>), an ESA press release<\/a>, and blog posts (Uncertain Principles, Something Similar<\/a>, and Illuminating Science<\/a>) today are all about a recent experiment performed by Martin Tajmar (ARC Seibersdorf Research GmbH, Austria) and Clovis de Matos (ESA-HQ, Paris) which they claim shows a gravitomagnetic effect in a laboratory experiment. Not only do they claim that they observe a gravitomagnetic effect, but that the effect comes not from the standard general relativity mechanism, but instead from their own theory which has massive photons and massive graviphotons (which is what the authors call the carriers of the force which arises when one linearlizes gravity and obtains equations which resemble Maxwell equations, i.e. spin 1 instead of spin 2)! Color me skeptical.
\nThe experiment is actually fairly straightforward. Just take a superconducting ring and spin it up. The authors then look for a gravitomagnetic field which can be measured by nearby accelerometers. Now the normal gravitomagnetic field strength measured in their experiment is about 30 orders of magnitude lower than what standard general relativity predicts. But when they run this experiment they indeed do find accelerations in their accelerometers for superconducting rings (and none for non-superconducting rings.) The authors then intepret this effect as confirming evidence of their theory which invokes “gravitophotonic” masses. If this is correct, then this is an astounding result: not only does it detect a gravitomagnetic field, but it also is a field which is not arising from standard general relativity. Wowzer.
\nOf course you can color me skeptical. As Chad Orzel points out, the signal they are talking about is only about 3 times as strong as their noise. Now when you look at one of their runs, i.e. figure 4 of gr-qc\/0603033<\/a>, the peaks look pretty good, no? Well figure 4b is a little strange: the gravitomagnetic effect appears to occur before the acceleration. Okay a bit strange, but a single run proves nothing, right? Okay, what about figure 5? Ignore the temperature dependence now, but would you have picked out the peaks that they picked out? Okay so these things make me a little uneasy. Okay, so well certainly they did a lot of runs and tried to get some statistics on the effect. Indeed, they did something like this. This is figure 6. And this is what makes the paper frustrating: “Many measurements were conducted over a period from June to November 2005 to show the reproducibility of the results. Fig. 6 summarizes nearly 200 peaks of in-ring and above-ring tangential accelerations measured by the sensor and angular acceleration applied to the superconductors as identified e.g. in Fig 4 with both electric and air motor.” Why is this frustrating? Well because I have no clue how they analyzed their runs and obtained the tangential accelerations. Were the peaks extacted by hand? (And what is the angular acceleration? Is it the average acceleration?) Argh, I can’t tell from the paper.
\nWell certainly this is a very interesting set of papers (the theory paper is pretty crazy: if I get a chance I’ll try to go through it in some detail and post on it.) I would personally love to know more about the experiment. I spent this afternoon pondering if I could think up a way in which they get the effect they do, but I’m certainly no expert on this stuff, and might be missing something totally obvious.
\n(Note also that there is another claim of interesting gravitational effects around superconductors made by Podkletnov. For a history of this “anti-gravity” effect see Wikipedia<\/a>. Since the Podkletnov experiment is considered controversial, the authors of the above article make sure to point out that they are not observing the effect Podkletnov claimed.)<\/p>\n","protected":false},"excerpt":{"rendered":"

Two papers (experiment: gr-qc\/0603033, theory: gr-qc\/0603032), an ESA press release, and blog posts (Uncertain Principles, Something Similar, and Illuminating Science) today are all about a recent experiment performed by Martin Tajmar (ARC Seibersdorf Research GmbH, Austria) and Clovis de Matos (ESA-HQ, Paris) which they claim shows a gravitomagnetic effect in a laboratory experiment. Not only … <\/p>\n

Continue reading “Gravitomagnetic London Moment?”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[53],"tags":[],"class_list":["post-1215","post","type-post","status-publish","format-standard","hentry","category-physics"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/dabacon.org\/pontiff\/wp-json\/wp\/v2\/posts\/1215","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dabacon.org\/pontiff\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dabacon.org\/pontiff\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dabacon.org\/pontiff\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/dabacon.org\/pontiff\/wp-json\/wp\/v2\/comments?post=1215"}],"version-history":[{"count":0,"href":"https:\/\/dabacon.org\/pontiff\/wp-json\/wp\/v2\/posts\/1215\/revisions"}],"wp:attachment":[{"href":"https:\/\/dabacon.org\/pontiff\/wp-json\/wp\/v2\/media?parent=1215"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dabacon.org\/pontiff\/wp-json\/wp\/v2\/categories?post=1215"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dabacon.org\/pontiff\/wp-json\/wp\/v2\/tags?post=1215"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}