Proposition 58, Theorem 21, concerning the motion of bodies drawn to one another by centripetal forces, from Newton's 'Principia Mathematica' (1687). This proposition posits that: 'If two bodies attract each other with any forces whatever and at the same time revolve about their common centre of gravity, I say that by the action of the same forces there can be described around either body if unmoved a figure similar and equal to the figures that the bodies so moving describe around each other.' The discoveries of English physicist and mathematician Isaac Newton (1642-1727) were prolific and hugely influential on science and thought. His work included the three laws of motion, the theory of gravitation, the law of cooling, the binomial theorem and the calculus.
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