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J.E. Chambers, Research Astronomer

Dr John Chambers has made detailed computer simulations of the origin and formation of the Earth and the inner planets. These build upon earlier work by Chambers and George Wetherill, of the Carnegie Institution of Washington, whose computer calculations had predicted that planets would tend to have elliptical orbits rather than the almost-circular ones we see in the Solar System. If true, this would have profound implications for the habitability of extra-solar planets, as elliptical orbits induce large swings in climate. The new simulations have a more interesting range of outcomes. Several calculations yielded Earth-like planets moving on almost circular orbits, which allows them to have stable climates. However, a significant fraction of planets are likely to have highly elliptical orbits, so that they are unlikely to be able to support life.

A new algorithm has also been developed for solving the N-body problem -- a tough computational task necessary to understand many aspects of astrophysics. In particular, the new method has considerably speeded up computer simulations of planet formation, making it possible to get a better understanding of how the Earth, the Moon, the planets, and the asteroids formed.

Michael Brown (a final-year student at Trinity College, Dublin) extended earlier work on the stability of planetary systems. He finds that many systems become unstable if one waits long enough. This instability is especially likely if the planets have a wide range of masses, due to the occurrence of chaotic motion generated by repeated configurations of the planets.

Other activities include:

1.

Successful application for an NRC grant (USA) for a one-year sabbatical to work at NASA/Ames Research Center, California. In-depth investigations of the origin of the Earth and Moon, the inner planets, and the asteroid belt will be carried out in collaboration with planet expert Dr Jack Lissauer.

2.

On-going research collaborations, for example with: J.J. Lissauer and E. Rivera at NASA/Ames Research Center, on the formation of the inner planets and the Moon; A. Morbidelli and J.-M. Petit at the Observatoire de Nice, on the origin and early evolution of the asteroid belt; M.A. Murison at the US Naval Observatory, on developing better computer algorithms for solving the N-body problem; G.W. Wetherill at Carnegie Institution of Washington on planet formation and the formation and evolution of the asteroid belt; N.W. Evans and S. Tabachnik at Oxford University, on possible primordial belts of asteroids in the inner solar system.

3.

Presentations: included lectures at University of Durham, the University of Oxford and Queen Mary College, London, on the origin of the terrestrial planets and on the formation of planetary systems. In addition, lectures were given at various national and international astronomy meetings, including Lisbon (Portugal), Namur (Belgium) and Madison (USA).