for Nereid. I'm not the only one thinking varying G, and thanks for the Eot-Wash link. pete

see:http://arxiv.org/ftp/physics/papers/0110/0110094.pdf

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A third rate theory forbids.
A second rate theory explains after the fact.
A first rate theory predicts.
A. Lomonosov

I read the first paragraph of the paper, and decided to give my take on, well, at least the first paragraph: the rate of change of the gravitational constant, G-dot per G being about 1/10000 per year seems awful fast to me--so fast that my intuition tells me it would invalidate projections of planetary and asteroid positions into history, despite it all seeming to match up in a neat consistent package (so that we even think we know which rocks made Tycho on the moon and killed the dinosaurs).

Unless it's for example a sine wave with amplitude on the order of 1/10000, that is.

I suspect that a paper based on 75 years of historical measurements is more likely measuring the errors in the measurements than actually finding anything (it seems to me that our ability to measure things accurately has gone up significantly even in just 75 years). Though if you wait 75 years and see the same effect over THIS period with more accurate measurements, that would mean something.

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Todd (Bowie, MD, US, North America, Earth, Sol System, Vega region, Local Bubble, Orion arm, Milky Way Galaxy, Local Group, Virgo A Cluster, Virgo supercluster, the universe in which spock is clean shaven)

Quidquid latine dictum sit, altum sonatur.

personal page: http://blog.astrosketches.info

I like the idea of a changing universal gravitational constant. It is especially interesting if you subsscribe to a sinusoidaly oscillating universe. It would then experience accelerations and decelerations in its expand/shrink velocity as it goes through its phases, and changes of such magnitude would presumably affect the universal constants as well.
Or as tdvance suggests, it might be a kind of jiggling happening in an otherwise calm and peaceful universe.
I have more trouble conceiving of unchanging universal constant values than I do with the changing ones.
OldAlbert

Oldalbert, if the universal "constants" vary as a function of time and space, do you believe that they change according to some physical law?

Fortis:
You may remember me as the guy who got stuck into the concept of a contracting universe (space and contents). My model for that was an oscillatory one, which alternates between, possibly near sinusoidaly, with 'c' being the instantaneous velocity of contraction at any particular place, and time in the cycle. At the moment of greatest expansion, c would be zero, and space would begin to contract, with the value of c increasing until the contraction began to decrease, then c would begin to decreas as a consequence. until it became zero again as the universe reached its smallest possible size, and began to expand. So that is ONE universal constant which is changing with time in a predictable fashion.
With such massive changes in the status of the universe going on, it seems inconcieivable to me that ANY universal constants could remain unchanged, even when measured with then 'current' values for length and time.

Of course if the universe is not cyclical as above, then all of the above is pie in the sky. but that model explains a lot of odd and hard-to-model physics, as well as making changes in universal constants seem probable.

But I beat that horse in an earlier thread.

OldAlbert