Jack Wisdom

Jack Leach Wisdom ( born January 28, 1953 in Lubbock, Texas) is an American physicist known for celestial mechanics studies, the evidence of chaotic behavior in the solar system services.

Wisdom studied at Rice University Physics ( bachelor's degree 1976) and doctorate in 1981 at Caltech. He is a professor of planetary science at MIT.

Wisdom is known for different results, which show chaotic behavior in celestial mechanics problems of our solar system. For example, he found Gerald Jay Sussman with signs that the orbit of Pluto is chaotic and compared to the orbits of the other outer planets on long time scales (simulated 845 million years were 1988 on the Digital Orrery ) is very complicated. After Jacques Laskar, 1989, a long- time simulation of the solar system (excluding Pluto) carried out for over 100 million years, showed signs of chaotic behavior, repeated and confirmed this Sussman and Wisdom on the supercomputer toolkit, a special-purpose computer for such simulations. The time scale for the formation of chaotic behavior (according to the Lyapunov exponent ) amounts to 4 to 5 million years.

One of the most obvious example of chaotic motion in the solar system is the orientation of the rotation axis and the rotation rate of the outer Saturn moon Hyperion, which Wisdom also examined. It is caused by a highly irregular shape and the weak tidal forces of Saturn and also occurs especially in appearance because of the large Ekzentrizität the web. After Wisdom chaotic phases occur at any irregularly shaped moon just before its rotation with the planet synchronized ( resonance case). With Touma he also showed that is exposed to the inclination of the axis of rotation of Mars to the orbital plane strong chaotic variations, with impacts on the Martian climate.

Wisdom also explained various gaps in the asteroid belt, such as the Kirkwood gap. They result from a coarse Although resonance with the orbital period of Jupiter ( at the Kirkwood gap in the ratio 3:1 ) to their exact explanation but is that enough not because of some resonance orbits no gap occurs. These were simulations of the orbits over long time periods required ( millions of years ), only then showed peaks in the Ekzentrizität the web which declared an out kicking and thus the formation of the gap.

For this he developed a new hand, numerical methods (such as a symplectic mapping of the gravitational N- body problem with Matthew Holman ), on the other hand, specialized computer hardware, such as the Digital Orrery in the 1980s with Sussman. The use of different methods also allowed to monitor each of the bills.

Wisdom also examined the Earth-Moon system and the development of the rotation parameters of the moon, Earth's core and mantle of the interaction, and the tidal effects that say " knead " the moon, driven volcanism on the Saturn moon Enceladus. He also dealt with the discovery of extrasolar planets (like 55 Cancri f).

Wisdom proposed in 2003 a locomotion mechanism in the general - relativistic space-time solely on the basis of changes in shape of the body before he called it swimming in the space-time ( Swimming in Spacetime ).

With Sussman and Mayer, he wrote an algorithm - oriented textbook of classical mechanics.

In 1986, he received the Harold C. Urey prize, the 1987 Helen B. Warner Prize and the 2002 Dirk Brouwer Award of the American Astronomical Society (AAS ). 1988 to 1994 he was a Presidential Young Investigator by the National Science Foundation. In 1994 he received a MacArthur Fellowship. He is since 1992 a member of the American Academy of Arts and Sciences and in 2008 the National Academy of Sciences.

Writings

• Gerald Jay Sussman with Meinhard E. Mayer: Structure and Interpretation of Classical Mechanics, MIT Press 2001
• Chaotic behavior in the solar system, Proceedings of the Royal Society A, Vol 413, 1987, pp. 109, online here pdf file