We have seen that the grand disparity that was believed to exist
between the way Nature works here on earth and in the heavens is
not valid. The question remains, however, can we learn
everything we need to know by investigating phenomena here on
earth and extending that result to the Universe at large? The
answer must be no for the following reasons: 1) Who would have
thought to look for a law of Universal gravitation without the
precise measurements and detailed analysis of Brahe and Kepler?
Cavendish's laboratory measurement of G was done in response to
interpret results obtained for the solar system. 2) Even if
someone would have used the Cavendish apparatus to map out the
gravitational force between two bodies, independently of knowing
Kepler's results, would we be able to infer a complete
understanding of celestial motion? No. We know Newton's Law of
Universal Gravitation is For example, there are certain aspects
of Mercury's motion that can not be explained using the
Newtonian form. The correct explana