DA this is part of a page from my book. It explains that Newton did not decipher the cause for the planets revolutions abot the sun or for that matter for satellites around planets.
I was of the view that Newton's law accounted for the revolutions of the planets. In an effort to get a little education, and not to over do it, 1 went back to the Internet, (Copied by be about March 10, 2005)
lltlG-//\YWw:.sgof.gsfc.na, s _a -goy/sta rgazc/Sgr ay it v. ht m (2/11/2005)
They provide, for me, the best and most understandable
outline on Newton's Laws and how to do the calculations.
I printed out 4 of the 5 pages.
On page two about 2/3rds of the way down the page they
recite:
"(Please note: gravity is not what gives the moon
its velocity. Whatever velocity the moon has was probably acquired when it was created. But gravity prevents the Moon from running away, and confines it to some orbit.)"
I should have found this source sooner. It seems that neither the basis for the planets revolutions or for their rotations was fully discovered before. I should have devoted more space to the issue, and would have, except that something I read implied that Newton's work explained the orbits and the forces working on the objects. When it comes to the sun and the planets I think we can conclude that it is the sun's source of gravity that provides for the orbits of the planets even though the mass of the planet does not appear to play any part whatever in the result. The velocities of the planets are related entirely to orbit distance.
jjw
