Halley's comet first sighted after he predicted its return. After Newton explained planetary motion, he suggested that comets could have elongated elliptical orbits. Halley's comet has eccentricity 0.967.
Wilhelm Kutta died in Germany. Best known in mathematics for the Runge-Kutta numerical method(s) for solving differential equations, he also made important contributions to aerodynamics, glaciers, and history of mathematics.