• Dr.
    • Jacques Laskar LTE
    • LTE, CNRS, Observatoire de Paris
    • Astronomy

Chaos in the Solar System. Historical perspective and new results.

More than thirty years ago, using extensively some dedicated computer algebra for averaging the planetary equations of motion, I demonstrated that the movement of the planets in the solar system is chaotic, which leads to the impossibility of predicting its movement over a period of more than 60 million years. Beyond that time, we can still make predictions, but only if we resort to a statistical approach. Over a period of the order of the age of the solar system, planetary collisions are even possible, with a probability of collision of Mercury within 5 Gyr of the order of 1%. Recently, within my collaborators, we looked again at this 350 years old problem of the stability of the solar system to clarify certain points left unresolved.

About

Jacques Laskar is an astronomer and research director at CNRS and the Paris Observatory, specializing in the dynamics of planetary systems. Building on the foundational work of Laplace and Lagrange, he pioneered the use of computer-based analytical calculations to reveal the chaotic behavior of the Solar System's planets over 35 years ago. His research demonstrated that the predictability of planetary motion is limited to approximately 60 million years and that planetary collisions could occur within less than 5 billion years. He also uncovered the highly chaotic nature of Mars' rotational axis and showed that Earth's axial stability relies on the presence of the Moon. For the past three decades, Laskar has provided the paleoclimate community with the most accurate models of long-term variations in Earth's insolation, significantly advancing our understanding of climate history. Awards and recognition : Member of the french Academy of Sciences (2003); Silver Medal from CNRS (1994) ; Brouwer Award from DDA/American Astronomical Society (2007); Milutin Milankovitch  Medal from European Geophysical Union (2019).

Awards and recognition

Member of the french Academy of Sciences (2003); Silver Medal from CNRS (1994) ; Brouwer Award from DDA/American Astronomical Society (2007); Milutin Milankovitch  Medal from European Geophysical Union (2019).