Re: Measuring acceleration of Earth
Title: Re: Measuring acceleration of
Earth
Oops! I wrote:
The difference in speeds is a LOT bigger
than that. The orbital speed of a point at the equator at
midnight approaches 31 km/s and at noon 29 km/s. This creates a
real diurnal variation in what would be observed as the the magnitude
of the gravitational field strength. However, it's easy to show that
the magnitude of the variation is no more than 8 angstroms/s^2, about
1 part in 10^10, so measuring it would certainly be at least VERY
difficult.
Oops! I guess my post election despair is coloring my
ability to do physics. (Not that the pre-election variety hadn't
already taken its toll.) I dropped a squared factor of km/m =
10^3 in my calculations. I should have said
the magnitude of the variation is no more than 0.8 mm/s^2,
about 1 part in 10^4, so measuring it should be quite
straightforward.
But then I have to wonder why this isn't better known. So I
suspect that both Rick and I are overlooking an important point
related to the fact that the instantaneous path of the object is never
a circle centered on the sun.
So never mind; pretend I wasn't here.
John Mallinckrodt
Cal Poly Pomona