Because of the chaotic nature of the Solar System, astronomers believed that it was impossible to obtain information about the position and the orbit of planets beyond 60 million years in the past. An international team of researchers from the US, France, China and the UK has now turned this idea on its head by showing that the analysis of geological records of climatic variations modulated by orbital changes can be used to extend such information further back in time – as long as 200 million years ago. The study has been published in PNAS.
The researchers used data from two scientific coring experiments in lake sediments (that they call the Geological Orrery, which is a record of climatic changes on Earth that can be extrapolated back into a larger map of solar system motions over hundreds of millions of years) from the Late Triassic and Early Jurassic epochs (roughly 220 to 199 million years ago). They succeeded in recovering precise and accurate values for the precision frequencies of the perihelion of Mercury, Venus, Earth, Mars and Jupiter.
Extending the Geological Orrery from 60 million years ago to the whole Mesozoic and beyond would help constrain models of Solar System evolution, further test the theory of General Relativity and its alternatives, constrain the existence of additional past planets, and provide further tests of gravitational models, says the team.
The French scientist involved in this study is Jacques Laskar from the Institut de mécanique céleste et de calcul des éphémérides (Observatoire de Paris – PSL/CNRS/Sorbonne Université/Université de Lille).
Reference: The Geological Orrery: Mapping Chaos in the Solar System. Paul E. Olsen, Jacques Laskar, Dennis Kent, Sean Kinney, David Reynolds, Jingeng Sha et Jessica Whiteside. Proceedings of the National Academy of Sciences
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