Gravity Probe B
May. 5th, 2011 04:57 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
mmcirvinVia Randy McDonald: Centauri Dreams summarizes the results of the Gravity Probe B experiment.
It's a bit of an anticlimax, since the results simply confirm the predictions of Einstein's general relativity, which is pretty much what everyone expected. (Also, my understanding is that other experiments have already provided somewhat less direct evidence for both of the effects being measured.) But those results are themselves peculiar; they concern the tiny effect on the precession of a gyroscope (in the form of an ultra-precise sphere magnetically suspended inside an orbiting satellite) from the curvature of space-time by the Earth's mass, and from the minute dragging of inertial frames by the Earth's rotation.
This is the most-delayed scientific experiment I know: I've been anticipating it for most of my life. The troubles in the Space Shuttle program knocked it for a loop. I remember Nigel Calder's description of the preparations for it in his pop book Einstein's Universe in the late 1970s. Still, it's a lovely, elegant result.
It's a bit of an anticlimax, since the results simply confirm the predictions of Einstein's general relativity, which is pretty much what everyone expected. (Also, my understanding is that other experiments have already provided somewhat less direct evidence for both of the effects being measured.) But those results are themselves peculiar; they concern the tiny effect on the precession of a gyroscope (in the form of an ultra-precise sphere magnetically suspended inside an orbiting satellite) from the curvature of space-time by the Earth's mass, and from the minute dragging of inertial frames by the Earth's rotation.
This is the most-delayed scientific experiment I know: I've been anticipating it for most of my life. The troubles in the Space Shuttle program knocked it for a loop. I remember Nigel Calder's description of the preparations for it in his pop book Einstein's Universe in the late 1970s. Still, it's a lovely, elegant result.
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Date: 2011-05-06 02:32 pm (UTC)I do notice, however, that this issue didn't make it into popular coverage of the final press release. Do you know anything about it?
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Date: 2011-05-06 02:50 pm (UTC)I had heard that there was indirect evidence for the frame-dragging effect from other space-based experiments, and that, for that reason, a result implying a violation of GR would probably not have been taken very seriously. Combined with the overall expense of the project, many people had wondered whether the whole thing was long past its sell-by date.