Galileo Galilei, made key improvements on the thermometer and telescope which allowed him to observe and clearly describe the solar system. Descartes was not only a pioneer of analytic geometry but formulated a theory of mechanics and advanced ideas about the origins of animal movement and perception. Vision interested the physicists Young and Helmholtz, who also studied optics, hearing and music. Newton extended Descartes' mathematics by inventing calculus (at the same time as Leibniz). He provided a comprehensive formulation of classical mechanics and investigated light and optics. Fourier founded a new branch of mathematics — infinite, periodic series — studied heat flow and infrared radiation, and discovered the greenhouse effect. Girolamo Cardano, Blaise Pascal Pierre de Fermat, Von Neumann, Turing, Khinchin, Markov and Wiener, all mathematicians, made major contributions to science and probability theory, including the ideas behind computers, and some of the foundations of statistical mechanics and quantum mechanics. Many mathematically inclined scientists, including Galileo, were also musicians.