Exploring the chaotic future and the deterministic past of the Solar System: an interview with Jacques Laskar

TL;DR

This paper discusses Jacques Laskar's groundbreaking work on the chaotic nature of the Solar System's long-term evolution and his contributions to understanding Earth's climate history.

Contribution

Laskar's 1989 numerical demonstration revealed the Solar System's chaotic evolution, enabling new insights into planetary motion and climate history.

Findings

The Solar System's long-term evolution is chaotic and unpredictable.

Numerical solutions developed by Laskar underpin astronomically calibrated timescales.

The AstroGeo project aims to reconstruct precise planetary motions using geological records.

Abstract

Jacques Laskar (1955–) is a preeminent French astronomer and celestial mechanician whose work has fundamentally reshaped our understanding of the Solar System’s long-term dynamics and Earth’s climate history. As a Research Director at the CNRS (French National Centre for Scientific Research) and at the Paris Observatory, he is widely known for his 1989 numerical demonstration that the Solar System’s long-term evolution is chaotic and therefore cannot be precisely predicted. He is also renowned for developing numerical astronomical solutions that underpin astronomically calibrated timescales. For these transformative contributions, he has received prestigious accolades, and an asteroid has been named after him. In recent years, he has focused on the AstroGeo project, which aims to invert geological records to infer past orbital parameters and reconstruct the precise planetary motions across large spans of geological time.

In December 2025, NSR spoke with Prof. Laskar in Beijing. During the conversation, he shared insights on the Solar System’s past, present and future, discussed his current research and reflected on his unusual career path, from a high-school teacher to a leading scientist.

NSR spoke with Jacques Laskar, a preeminent French celestial mechanician whose work has fundamentally reshaped our understanding of the Solar System’s long-term dynamics and Earth's climate history.

Figures