Classical physics

In the autumn of 1684, the astronomer Edmond Halley traveled to Cambridge to ask Isaac Newton a single question: if the Sun pulls the planets with a force that weakens as the square of the distance, what shape orbit results? Newton answered immediately — an ellipse — and told Halley he had already worked it…

In 1687, a reclusive Cambridge professor published a book that did something no one had managed before: it explained, in one mathematical framework, why apples fall, why the Moon doesn’t fall into the Earth, why the tides rise and fall, and why the planets trace the paths Kepler had spent a decade calculating from Tycho…