Newton's Laws of Motion and Universal Gravitation

Newton's Principia Mathematica (1687) provided the first unified mathematical framework for both terrestrial and celestial motion, proving that nature obeys discoverable mathematical rules. His three laws and universal gravitation explained planetary orbits, the Moon's stability, and free fall with unprecedented precision. The theory's predictive power was demonstrated by successfully forecasting Halley's Comet's return in 1758—a 50-year projection—and later guided every Apollo mission and satellite launch. Unlike earlier ad hoc models that treated Earth and heavens separately, Newton's single set of equations still govern orbital mechanics today, making this the foundational act of modern science.