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Jack G. Hills
Jack Gilbert Hills (born 15 May 1943) is a theorist of stellar dynamics. He worked on the Oort cloud; the inner part of it, the Hills cloud, was named after him. He studied at the University of Kansas, where he was awarded an A.B. in 1966 and an M.A. in 1967. He was also awarded an M.S. by the University of Michigan, Ann Arbor. He spent much of his professional career at Los Alamos National Laboratory, which named him a Laboratory Fellow in 1998. The Hills mechanism in astrophysics is also named after him. He proposed the mechanism in the 1980s. He was inducted a Fellow of the American Physical Society in 1983. His citation read that he was proposed for "seminal theoretical work on the physics of dense stellar systems and in particular for proposing and developing his model of the energy source of quasars." References External links * * 1943 births Living people University of Kansas alumni University of Michigan alumni American astronomers 20th-century Amer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Dynamics
Stellar dynamics is the branch of astrophysics which describes in a statistical way the collective motions of stars subject to their mutual gravity. The essential difference from celestial mechanics is that the number of body N \gg 10. Typical galaxies have upwards of millions of macroscopic gravitating bodies and countless number of neutrinos and perhaps other dark microscopic bodies. Also each star contributes more or less equally to the total gravitational field, whereas in celestial mechanics the pull of a massive body dominates any satellite orbits. Connection with fluid dynamics Stellar dynamics also has connections to the field of plasma physics. The two fields underwent significant development during a similar time period in the early 20th century, and both borrow mathematical formalism originally developed in the field of fluid mechanics. In accretion disks and stellar surfaces, the dense plasma or gas particles collide very frequently, and collisions result in equ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
