Re: Measuring acceleration of Earth

[Bernard Cleyet <anngeorg@PACBELL.NET>]

"... and will share later, if I haven't by then moved to Fiji."

Is this  political statement?

bc, fortunate in having EC citizenship.

p.s. isn't there also a slight semiannual variation due to elliptical orbit?  [Not certain JD's NASA reference includes, tho implied, this.



John Mallinckrodt wrote:

> Driven both by humiliation and escapism, I have devoted some more
> time to thinking about this problem and I believe I now understand
> something I never appreciated before: The apparent gravitational
> field strength undergoes a relatively large (first order in the ratio
> of the radius of the Earth to that if its orbit) SEMI-diurnal
> variation due to the rotation of the Earth, and a MUCH smaller
> (second order) diurnal variation.
>
> To first order, I find that g is the same at noon and midnight and
> both values are smaller than that at dawn and dusk by about
>
>     delta g = 2 G M_sun R_earth/(R_orbit)^3 ~ half a micrometer/s^2
>
> I am going to try to write up a brief analysis, which serves, I
> think, as a very nice illustration of the use of the equivalence
> principle) and will share later, if I haven't by then moved to Fiji.
>
> John Mallinckrodt
> Cal Poly Pomona