Gravity Probe B

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21 years 1 month ago #6759 by tvanflandern
<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by glittle</i>
<br />Tom, could you make some "predictions" about what should be found? Do you expect any results that will help differentiate between the "standard" theory and the MetaModel?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Before theories can be differentiated, they must first make predictions. I have yet to see specific predictions made by GR. Nor do I have details of the planned orbit so that MM could make them.

One possible reason is that the experimenters intend to wait and see what happens, then come up with an explanation. -|Tom|-

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19 years 2 months ago #14502 by Michiel
Replied by Michiel on topic Reply from Michiel
Well, GP-B finally ran out of Helium, used for drag-free operation. It looks like the mission is a success. The worst problems involved multi-bit computer errors due to radiation. But most of the time the probe was working just fine. That's a relief, because the project took $700,000,000 and over 40 years to realize.

Now it's time for the data to be evaluated. This will take something like a year and we won't hear a thing until then. So there's enough time to make your own predictions...

___

Here's some info on GP-B. It's from:
einstein.stanford.edu/content/fact_sheet/GPB_FactSheet-0405.pdf


Gyroscopes.

Number: 4
Shape: spherical (less then 40 atomic layers from perfect)
Diameter: 3.8 cm
Composition: Homogenous fused quartz
Spin Rate: 72 Hz average

Predicted drift.

Geodetic Effect: 6.61 arcseconds ( 1.84 *10^(-3) degrees ) per year
Frame-Dragging: 0.041 arcseconds ( 1.14 *10^(-5) degrees ) per year

Orbit.

Characteristics: polar orbit at 642 km
Semi-major axis: 7027.4 km
Eccentricity: 0.0014
Apogee altitude: 659.1 km
Perigee altitude: 639.5 km
Inclination: 90.007 degrees
Right Ascension of ascending node: 163.26 degrees

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19 years 2 months ago #14435 by PhilJ
Replied by PhilJ on topic Reply from Philip Janes
Michael supposedly, according to the G&R topic summary, posted a message here yesterday at 22:52:26. The latest message that I can view was posted at 11:18:17. This is a frequent problem with the forum software.

[EDIT] This msg posted okay, but I still don't see MIchael's latest post.

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19 years 2 months ago #12683 by Larry Burford

I've noticed this too. It may or may not be a bug, but it seems to work this way:

When someone makes an edit to their post, the time stamp on the summary page shows the edit time while the time stamp on the post itself show the original post time.

LB

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19 years 2 months ago #12805 by Michiel
Replied by Michiel on topic Reply from Michiel
Hmm yeah. I just edited the post. Where it said 'altidude' it now says 'altitude' , which seems more appropriate.

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18 years 11 months ago #17282 by Michiel
Replied by Michiel on topic Reply from Michiel
From the GP-B Update (30-12-2005):

"...Our science data analysis is proceeding according to plan. We are in the process of analyzing approximately 1 terabyte (1,000 gigabytes) of data collected from the spacecraft. Two independent analysis teams here at GP-B are working on the data, ..."

Hmm nice

"...frequently comparing their results for both quality control and to ensure the validity of the data analysis algorithms."

Huh?

"...The main part of the data analysis is expected to be completed late this summer (July-August 2006). At this point, the Harvard-Smithsonian Center for Astrophysics (CfA) will provide our science team with their ultra-precise measurements of the proper motion of the guide star, IM Pegasi. In the final step of the analysis, our science team will combine the gyroscope results with the CfA proper motion measurements of IM Pegasi to arrive at the final experimental results. ..."

That sounds good, until the final step there is no 'working towards the answer'

"...These results will then be carefully and critically reviewed by international experts in general relativity and data analysis to ensure that our statement of the effects observed are as accurate as possible. Only after this review is complete--early in 2007--will we make a formal and public announcement about the results of this unprecedented test of General Relativity."

I guess the results will be carefully and critically reviewed by anyone who has an interest in real physics.

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