Gee silly! Of course you have to consider horizontal displacement of the earths crust as the tidal forces move about, being different depending on the density of the body in question....
BTW, would a moon clock have a inset face that shows the phases of the earth?
-Bruce
That's actually true only if the body is homogeneous. The Moon is not--Lunar mass concentrations were discovered by their effect on the motion of the Lunar Orbiter satellite, which orbit would not have been perturbed by them if your contention was correct.
However, if our clock is in a fixed location on the lunar surface then the effect of any nearby mass concentration would be accounted for when the clock was regulated--that would only be an issue if the clock was moved around, and even then I suspect it would be a very small effect.
Libration would have some effect--objects on the surface of a macroscopic body in orbit about the other (or to be pedantic about their common center of mass) are subject to tidal stresses which would affect the rate of a pendulum clock, however most of that would againb be accounted for when the clock was regulated, with libration being the only significant variable in that regard. But again I suspect that that would be a very small effect.
it's all a bit fuzzy now but I seem to remember reading sometime in the last few years an article about the moon and it's orbital relationship with Terra. yes, one side always faces the earth, sorta. the moon wobbles quite a bit. the "back" side does have a bit of area that has never been visible to earth, but it's a lot smaller than you might think.
yup.
but in relation to the sun the moon *does* spin. the effects of gravity obey the square of the distance bit, and the sun is a long way away, but it's also freakin' huge. nothing compared to the grav effect of Terra, but non-trivial.
and the moon is basically a rock, though there is some recent data indicating that it may have a squishier core than previously thought.
Ask the Addams family what they have on their moondial.
I'm surprised with over 40 posts, that no one has mentioned the effect gravity has on time. While the pendulum will have the largest effect for this experiment, EVERY clock, regardless of type be it atomic, spring, quartz, etc, will run faster on the moon due to the lower gravity. Einstein's general theory of relativity.
But, but,... The moon is moving -faster- than the earth, whenever the moon is more than 1/2 full, time is -slower- on the Moon, due to velocity effects. To an observer outside the Earth-Moon, that is.
Granted, the velocity of the moon has to be considered but it is an additional factor and all relatavistic effects have to be taken into account, as it is in the GPS satellite system.
General relativity in the global positioning system
By Sun, 16 May 2004 16:29:18 -0500, Hoyt Weathers decided to post "Waaay OT- Lunar physics question" to rec.woodworking:
Hoyt, In deciding on using a division of the physical properties of the earth to help create a universal (almost) system of measurement, of about
1/10,000,000 of 1/4 of half of a complete meridian passing through France-- which they messed up anyway because of several factors, not the least of which was failing to recognize completely the true oddity of the shape of this ball we live on -- the French Academy rejected a measurement based on moment of pendulums of given arc at a certain latitude mostly because they determined that local distortions of gravity, such as provided by mountains, would fail to provide the exactitude which these astronomers wished for their standard. Such a measurement taken over a fixed period of time, at one given location, would not necessarily match that of another at another location. Other factors, such as measuring the length of the pendulum, determining the timing of the swing, atmospheric density and the quality and repeatability of the observations, to name but a few, all proved that a pendulum (eg clock) was not really that accurate. Given all of this, I think that if you wish to measure time on the moon, you would do better with a Swatch or Timex, at the very least.
/ts
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.