We are the Borg.
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- Joined: Mon Jun 07, 2004 1:33 pm
- Title: Yes, that one.
- Location: Chicago
Pulsar-white dwarf binary system confirms general relativistic frame-dragging
A century after it was first theorized, researchers have detected the effects of Lense-Thirring precession - an effect of relativistic frame-dragging - in the motion of a distant binary star system, a new study reports.
The results of the twenty-year study confirm a prediction of Einstein's general theory of relativity. When a massive object rotates, general relativity predicts that it pulls the surrounding spacetime around with it, a phenomenon known as frame-dragging.
The arc of the moral universe bends towards chaos.
People who believe God or History are on their side provide the chaos.
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Gravity Probe B
Gravity Probe B (GP-B) was a satellite-based mission to test two unverified predictions of general relativity: the geodetic effect and frame-dragging. This was to be accomplished by measuring, very precisely, tiny changes in the direction of spin of four gyroscopes contained in an Earth satellite orbiting at 650 km (400 mi) altitude, crossing directly over the poles.
The satellite was launched on 20 April 2004 on a Delta II rocket. The spaceflight phase lasted until 2005; its aim was to measure spacetime curvature near Earth, and thereby the stress–energy tensor (which is related to the distribution and the motion of matter in space) in and near Earth. This provided a test of general relativity, gravitomagnetism and related models. The principal investigator was Francis Everitt.
Initial results confirmed the expected geodetic effect to an accuracy of about 1%. The expected frame-dragging effect was similar in magnitude to the current noise level (the noise being dominated by initially unmodeled effects due to nonuniform coatings on the gyroscopes). Work continued to model and account for these sources of error, thus permitting extraction of the frame-dragging signal. By August 2008, the frame-dragging effect had been confirmed to within 15% of the expected result, and the December 2008 NASA report indicated that the geodetic effect was confirmed to better than 0.5%.
In an article published in the journal Physical Review Letters in 2011, the authors reported analysis of the data from all four gyroscopes results in a geodetic drift rate of −6601.8±18.3 mas/yr and a frame-dragging drift rate of −37.2±7.2 mas/yr, in good agreement with the general relativity predictions of −6606.1±0.28% mas/yr and −39.2±0.19% mas/yr, respectively.
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- Joined: Sat Aug 12, 2006 2:01 am
- Title: Hmmm ...
- Location: USA
Octohats still impress
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"Science and Mother Nature are in a marriage where Science is always surprised to come home and find Mother Nature blowing the neighbor."
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