[time-nuts] Result of Earth Quake speeds up earth?
bruce.griffiths at xtra.co.nz
Sun Mar 20 04:59:37 UTC 2011
>> A 10-12m diameter dish is probably close to the minimum feasible
>> 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?
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
> 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?
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