Two-hundred and twenty three. That is the number of articles
and papers that Gillies collects for listing in his resource letter. All of
these papers deal with Newtonian gravitation in some way, shape, or form. There
exists, today, even more articles and papers that examine it further. What is
the meaning of the startling weakness of the gravitational constant, G? How
does that interact with the other fundamental laws?
These questions are all questions that are constantly being
asked by scientists the world over. The reason why I wanted to point out this
article that is a collection of work is because it shows just how much a single
constant in physics can attract attention.
In more recent times, we are all aware of the search for the
Higgs. What does the Higgs mean? What can we do with it? There is still a ton
of work to be done, but that is something from recent times. The concept of
universal gravitation and its corresponding constant date back to the time of
Newton!
Getting an accurate and precise measurement for G is
extremely difficult. A simple way, at least in setup, would be what Cavendish
did to measure the force of gravity between masses, but even then, to get any
real accuracy or precision might have your hair going grey if my experience
with it is any indication.
What does this all mean for students? For one thing, I think
it can be reassuring to them. It shows that there is a lot more to yet learn in
physics about stuff that we have known for a considerable amount of time. There
are always new theories being proposed and new experiments being designed. That
can get them to have some wide-eyed wonder perhaps.
I think it also shows that building upon the p-prim idea
allows for this advancement. You can go from the concept of objects attracting
each other to describing how and why they do so. Then you can break down to the
specifics in the equations used to model the motion of the system. You can explore
each constant and variable that you use.
We know a lot and have a lot of ideas about what we aren't
sure about yet. Gillies shows us 223 papers worth of information on a single
constant. Just imagine how many more will exist in not even three years' time.
G. T. Gillies, "Resource Letter MNG-1: Measurements of Newtonian Gravitation," American Journal of Physics, Vol. 58, pages 525-534 (1990)
