**George Hill** was an American astronomer and mathematician. who worked on the three-body problem and later on the four-body problem.

- It had been an institution of higher education from 1766 and had been renamed Rutgers College thirty years before Hill studied there.
- Hill had graduated just before the Morrill Act of 1862 led to Rutgers College becoming New Jersey's land-grant college in 1864.
- Certainly Hill's undergraduate studies at Rutgers College were highly unusual for American students of this period.
- Strong had a fine library of classic mathematics texts which he was pleased to allow the talented undergraduate Hill to study.
- Hill graduated from Rutgers College in 1859 with his A.B. The following year he began his study of the lunar theory of Delaunay and Hansen.
- In 1861 Hill joined the Nautical Almanac Office working in Cambridge, Massachusetts.
- This suited the reclusive Hill who prefered being on his own.
- Hill was the first to use infinite determinants to study the orbit of the Moon in On the part of the motion of the lunar perigee which is a function of the mean motion of the sun and moon.
- Newcomb persuaded Hill to develop a theory of the orbits of Jupiter and Saturn and Hill's work on this topic is another major contribution to mathematical astronomy.
- Hill's most important work dealt with the gravitational effects of the planets on the Moon's orbit so in this work he was considering the 4-body problem.
- Examples of papers he published in the Annals of Mathematics include: On the lunar inequalities produced by the motion of the ecliptic (1884), Coplanar motion of two planets, one having a zero mass (1887), On differential equations with periodic integrals (1887) (these differential equations are now called Hill's differential equation), On the interior constitution of the earth as respects density (1888), The secular perturbations of two planets moving in the same plane; with application to Jupiter and Saturn (1890), On intermediate orbits (1893), Literal expression for the motion of the Moon's perigee (1894) and Application of Chebyshev's principle in the projection of maps (1908).
- Hill worked on very similar problems to Adams.
- It is no coincidence that Adams was also led to investigate infinite determinants and he did this work quite independently of Hill.
- Hill was elected to the National Academy of Sciences (United States) in 1874.
- Hill was president of the American Mathematical Society from 1894 to 1896 delivering his presidential address on Remarks on the progress of celestial mechanics since the middle of the century.

Born 3 March 1838, New York, USA. Died 16 April 1914, West Nyack, New York, USA.

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Astronomy, Origin Usa, Physics

**Oâ€™Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive