George William Hill | |
|---|---|
 George William Hill | |
| Born | (1838-03-03)March 3, 1838 New York City, U.S. |
| Died | April 16, 1914(1914-04-16) (aged 76) West Nyack, New York, U.S. |
| Alma mater | Rutgers University |
| Known for | |
| Awards |
|
| Scientific career | |
| Fields | Astronomy,mathematics |
| Institutions | Columbia University,United States Naval Observatory |
| Academic advisors | Theodore Strong |
| Signature | |
 | |
George William Hill (March 3, 1838 – April 16, 1914) was an Americanastronomer andmathematician. Working independently and largely in isolation from the wider scientific community, he made major contributions tocelestial mechanics and to the theory ofordinary differential equations. The importance of his work was explicitly acknowledged byHenri Poincaré in 1905. In 1909 Hill was awarded theRoyal Society'sCopley Medal, "on the ground of his researches in mathematical astronomy". Hill is remembered for theHill differential equation, along with theHill sphere.
Hill was born inNew York City to painter and engraverJohn William Hill and his wife, Catherine Smith. He moved toWest Nyack with his family when he was eight years old. After high school, Hill attendedRutgers College, where he became interested in mathematics.
At Rutgers, Hill came under the influence of professorTheodore Strong, who was a friend of pioneering US mathematician and astronomerNathaniel Bowditch. Strong encouraged Hill to read the great works onanalysis bySylvestre Lacroix andAdrien-Marie Legendre, as well as the treatises onmechanics and mathematical astronomy byJoseph-Louis Lagrange,Pierre-Simon Laplace,Siméon Denis Poisson, andGustave de Pontécoulant.
Hill graduated from Rutgers College in 1859, with aBachelor of Arts degree. In that same year he published his first scientific paper, on the geometrical curve of adrawbridge. Two years later he earned a prize from theRunkle Mathematical Monthly for his work on the mathematical theory of thefigure of the Earth.
In the early 1860s, Hill began studying the works onlunar theory byCharles-Eugène Delaunay andPeter Andreas Hansen, which would inspire and motivate most of Hill's subsequent research. In 1861, Hill was hired byJohn Daniel Runkle to work in theUnited States Naval Observatory's Nautical Almanac Office, based inCambridge, Massachusetts.[1]
In 1862 Rutgers awarded Hill aMaster of Arts degree. Hill lived for a while in Cambridge and later inWashington, D.C., but he preferred to carry out his mathematical work in his family farm in West Nyack, to which he retired for good after 1892.
Hill's mature work focused on the mathematics of thethree-body problem,[2] and later the four-body problem, to calculate the orbits of theMoon around theEarth, as well as that ofplanets around theSun. Hill was able to quantify the gravitational sphere of influence of an astronomical body in the presence of other heavy bodies, by introducing the concept of thezero-velocity surface. The space within this surface is called theHill sphere, which corresponds to the region around a body within which it may capture satellites.
In 1878, Hill provided the first complete mathematical solution to the problem of theapsidal precession of the Moon's orbit around the Earth, a difficult problem inlunar theory first raised inIsaac Newton'sPrincipia Mathematica of 1687.[3] This same work also introduced what became known in physics and mathematics as the "Hill differential equation", which describes the behavior of aparametric oscillator and which made an important contribution to the mathematicalFloquet theory.
Hill's work attracted the attention of the international scientific community, and in 1894 he was chosen as president of theAmerican Mathematical Society, serving for two years. Hill lectured atColumbia University from 1898 to 1901, but he attracted few students and he ultimately chose to return his salary and to continue working alone in his home in West Nyack, rather than within academia.[4]
Hill'sCollected Works were published in 1905-07 by theCarnegie Institution for Science, with a 12-page introduction by the eminent French mathematician and theoretical physicistHenri Poincaré. In that introduction, Poincaré said that, in Hill's 1878 article titled "Researches in the lunar theory", "one is allowed to perceive the germ of most of the progress that [celestial mechanics] has made ever since".[3] Of Hill's isolation from the academic community, Poincaré declared that
This reserve, I was going to say this savagery, has been a happy circumstance for science, because it has allowed him to complete his ingenious and patient researches.[3]
George William Hill was elected as a foreign member of theRoyal Society of London in 1902. He also became a member of theRoyal Society of Edinburgh in 1908, and of the scientific academies of Belgium (1909), Norway (1910), Sweden (1913), andthe Netherlands (1914).[5] His later years were marked by poor health, and he died in West Nyack in 1914. He never married and had no children.
Quotations related toGeorge William Hill at Wikiquote| International | |
|---|---|
| National | |
| Academics | |
| People | |
| Other | |
