Re: Measuring acceleration of Earth

[John Mallinckrodt <ajm@CSUPOMONA.EDU>]

John Denker wrote:

> I assume (based on the general context of this thread) that
> only solar (not lunar) contributions are being discussed.

Of course, John is correct; the formula given in my previous post
applies to the magnitude of the (nearly) semi-diurnal variations due
to the interaction with the moon and (as most already know from
consideration of the tides) the result is that the moon has roughly
twice the effect of the sun.  This is because the ratio of the moon's
mass to the cube of its distance is roughly twice that for the sun.

It's remarkable (and embarrassing) to me that I knew all these
results before, but didn't really appreciate how simple it is to
understand the first order/second order nature of the
semi-diurnal/diurnal variations (respectively) using only the
principle of equivalence.

John Mallinckrodt
Cal Poly Pomona