From 65438 to 0679, Newton returned to the study of mechanics: gravity and its influence on planetary orbits, Kepler's laws of planetary motion, and discussions with Hooke and Flamsteed on mechanics. He attributed his achievement to the book Motion of Objects in Orbit (1684), which contains a preliminary law of motion formed in principle later.

Second, math scores.

Most modern historians believe that Newton and Leibniz independently developed calculus and created their own unique symbols for it. According to people around Newton, Newton put forward his method several years earlier than Leibniz.

But he hardly published anything before 1693, and he didn't give a complete account until 1704. At the same time, Leibniz published a complete description of his method in 1684.

Third, optical achievements.

Newton devoted himself to the study of color phenomena and the nature of light. 1666, he studied sunlight with a prism and came to the conclusion that white light is a mixture of different colors (that is, different wavelengths), and different wavelengths of light have different refractive indexes.

Among visible light, red light has the longest wavelength and the smallest refractive index. Violet light has the shortest wavelength and the largest refractive index. This important discovery of Newton became the basis of spectral analysis and revealed the secret of light color.

Newton also pressed the convex surface of a fine grinding convex lens with a large radius of curvature on a very smooth flat glass. Under the irradiation of white light, we can see that the contact point of the center is a dark point, surrounded by a concentric circle of light and dark.

Later generations called this phenomenon "Newton's Ring". He founded the "particle theory" of light, which reflected the essence of light movement from one side, but Newton did not object to the "wave theory" of light.

Fourth, hot achievements.

Newton established the law of cooling, that is, when there is a temperature difference between the surface of an object and its surroundings, the heat lost per unit area per unit time is directly proportional to this temperature difference. ?

Verb (abbreviation of verb) astronomical achievements

Newton made reflecting telescope in 1672. He used the universal gravitation between particles to prove that the external gravitation of a spherically symmetric sphere can be replaced by particles with the same mass in the center.

He also explained various phenomena of tides with the principle of universal gravitation, pointing out that the magnitude of tides is not only related to the phase of the moon, but also related to the orientation of the sun. Newton predicted that the earth was not a right sphere. Precession is caused by the disturbance of the equator by the sun.

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