[time-nuts] Result of Earth Quake speeds up earth?

Bruce Griffiths bruce.griffiths at xtra.co.nz
Sun Mar 20 04:59:37 UTC 2011


jimlux wrote:
>
>>
>> A 10-12m diameter dish is probably close to the minimum feasible 
>> aperture.
>> A 4m dish can be made to work in conjunction with a mauch larger dish
>> (eg 30m).
>>
>
> The original speculation was for measuring the small change in earth 
> rotation rate, for which some sort of interferometric measurement of a 
> stellar source could be used.
>
> The source has to be bright (so you can detect it with a practical 
> antenna.. not everyone has a 30m dish in their back yard)
> The source has to be small angle (or at least something that you could 
> accurately determine the centroid of)
> The source has to be "not moving"  (which I think leaves out using 
> something like jupiter)
> The frequency of measurement has to be somewhere that the atmosphere 
> won't dominate the uncertainty (leaving out optical, I think)
>
>
> SO what's the brightest small angular radio source out there?

3C273

RA 12:29.1 DEC 02:03.1

>
>
> As someone else has pointed out, measuring the earth surface position 
> relative to spacecraft orbits, e.g. GPS, would be another technique.  
> In fact, a high resolution measurement of the position of a geosync 
> sat might do.. If the earth's rotation rate changes you'd have to 
> adjust the height of the satellites in Clarke orbit to keep them 
> stationary.
>
> Unfortunately, for earth orbiters, there's enough other perturbations 
> that you probably can't see it.  They already have to move satellites 
> around to compensate for things like solar wind, air drag (for LEO), etc.
>
> But maybe for a spacecraft in deep space, between planets, which is on 
> a well understood trajectory?
>
>
Bruce





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