Gravity Probe B and 'frame dragging'

In summary, the conversation discusses the potential findings of Gravity Probe B, which aims to prove that the rotation of the Earth causes frame dragging and linear dragging. However, the results are still being analyzed and the frame dragging effect may be too small to be detected. The conversation also considers the possibility that the Earth's forward motion may be causing a latent frame dragging effect.
  • #1
Ian
88
1
Am I right in assuming that Gravity Probe B has proved that the rotation of the Earth (@~465metres /sec.) 'swirls' space-time in the same sort of way that a rotating ball will swirl a fluid?

I ask because if this is the case, then the forward motion of the Earth (@~360km/sec.) must also produce a linear dragging which is detectable, much like a speedboat leaves a wake in it's path.

Also, if the rotating mass of the Earth causes frame dragging then common sense insists that matter must also 'displace' space time in a manner similar to Archimedes principle.
 
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  • #2
Hi Ian,

as far as I lnow after over forty years in the making they are still analysing the data of gravity probe B and we are still waiting for the 2 sigma confidence level results. The frame dragging effect is microscopic and was unfortunately swamped by noise in the data that is something like a hundreds times larger than the signal they are looking for, which is why it is taking so long to analyse.

Not sure about the linear dragging effect.

A good thread monitoring the progress of Gravity Probe B results is here https://www.physicsforums.com/showthread.php?t=104694&page=20
 
  • #3
Ian said:
I ask because if this is the case, then the forward motion of the Earth (@~360km/sec.) must also produce a linear dragging which is detectable, much like a speedboat leaves a wake in it's path.
.

Maybe not. I think the Michelson Morley type tests would have detected it. More likely the forward motion of the Earth is orbiting synchronously with a latent frame dragging caused during the origin of the solar system.
 

Related to Gravity Probe B and 'frame dragging'

What is Gravity Probe B?

Gravity Probe B (GP-B) was a satellite-based physics experiment launched by NASA in 2004 to test Einstein's theory of general relativity. It aimed to measure the effects of frame dragging, a phenomenon predicted by Einstein's theory where the rotation of a massive body (like Earth) causes a distortion in the fabric of spacetime.

What is "frame dragging"?

Frame dragging is the phenomenon where the rotation of a massive body causes a distortion in the fabric of spacetime. This effect was predicted by Einstein's theory of general relativity and is a key aspect of the GP-B experiment.

Why was GP-B launched?

GP-B was launched to test Einstein's theory of general relativity by measuring the effects of frame dragging. This was a crucial test for the theory, as it had not been directly observed before. The results of the experiment would either confirm or challenge the predictions of general relativity.

How did GP-B measure frame dragging?

GP-B used four gyroscopes, which were the most precise and stable ever built, to measure the tiny shifts in their orientation caused by frame dragging. The gyroscopes were placed in a polar orbit around Earth and were kept in a superconducting state to minimize interference from external forces. The rotation of Earth would cause a slight twist in the gyroscopes' orientation, which could be measured to determine the amount of frame dragging.

What were the results of the GP-B experiment?

The results of the GP-B experiment were consistent with Einstein's theory of general relativity. The measured value of frame dragging was within 0.28% of the predicted value, providing strong evidence for the validity of the theory. This was a major achievement in the field of physics and further solidified Einstein's groundbreaking work on gravity.

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