20 MAY 2019

Deputy Director of the Dynamic Meteorology Laboratory (LMD)1 and specialist in the exploration of the solar system and planetary environments, François Forget obtained an ERC Advanced for his project Mars Through Time.

François Forget
François Forget © Sorbonne University - Pierre Kitmacher

As a child, he dreamed of exploring the seabed. Finally, his research has taken him much further: beyond the confines of the solar system. After a thesis on the study of Mars in 1996, he became a CNRS researcher at the LMD in 1998. Within the team Planetology2 that he created in 2003, he studied the climate and atmospheres of terrestrial planets3 of the solar system (Mars, Venus, Pluto, Titan, Triton) and exoplanets4. In collaboration with the Atmosphere, Mediums, and Spatial Observations laboratory and other teams around the world, the LMD is developing digital climate models to simulate environments of these other worlds. Their applications are numerous: to analyze space observations, prepare robotic missions, study the habitability of exoplanets or better understand the Earth.

"The specialty of the LMD is to develop digital climate models. In our team we apply this know-how to the planets of the solar system and exoplanets. Studying the climate of these other worlds helps us better understand the Earth's climate change, "says the astrophysicist.

After working at NASA from 2004 to 2005, he has continued to be involved in a number of space missions such as Mars Express (ESA), the ExoMars Trace Gas Orbiter (ESA),New Horizons (NASA), Insight (NASA) or the Rover ExoMars (ESA).

CNRS Bronze Medalist in 2001 and elected member of the French Academy of Sciences in 2017, he received the David Bates Medal of the European Union of Geosciences in 2014 for his work on modeling the climate of the planets in the solar and extrasolar system.

A red planet with a thousand faces

Awarded an ERC Advanced in the spring of 2019, his Mars Through Time project aims to create a "new generation" climate change model on Mars to better understand its geology, habitability and changes.

The ERC Advanced Grant, a European Grant of Excellence

The European Research Council (ERC) program funds scientific excellence at the frontier of knowledge.

These are extremely competitive funding awards and Advanced Grant Scholarships enable experienced and recognized scientists as outstanding leaders in their field to carry out an innovative and ambitious exploratory research project.
The fellowship is for 5 years and the selection criteria are the scientific excellence of the project and the researcher who carries it.

Indeed, many observations of the surface of Mars have shown that the red planet has known, through the ages, multiple forms as a consequence of very different climates.

Visible on the surface of the planet, 3-billion-year-old lands testify to the presence of lakes, rivers, perhaps even oceans that have disappeared. This planet, half the size of the Earth and with a tenuous atmosphere, was able to see the birth of life long before it appeared on our own planet. The existence of large glaciers in more recent underground reservoirs shows that at other times in its history, the red planet had glacial ages during which it was partly covered with a mantle of ice.

Thanks to satellites and space missions, researchers have accumulated very precise information on the different aspects of Earth’s little sister, on its geology and its topology.

"Today we know the surface of Mars better than the surface of the Earth, which is partly covered by the oceans," says François Forget.

In the early 2000s, LMD researchers began to design, models from these observations, to simulate the evolution of Martian environments. While this work has been essential to advance knowledge, some of the underlying assumptions are now being challenged.

"In these models, we neglected some details," says the researcher. “For example, the water clouds on Mars are extremely thin, so we did not take into account. We now know the importance of their contribution to climate change. "

According to François Forget, the approximation of these hypotheses is also explained by the volume and difficulty of the calculations required to run the models. Previous IT solutions that were available did not provide sufficient performance for high-resolution simulations. To reduce computing time, scientists were forced to lower the level of resolution, which was not able to correctly represent the topography of the planet or to take into account the details of its surface in order to design more accurate models.

Simulate the evolution of Mars in the smallest detail and over millions of years

In his ERC project, François Forget wanted to meet this scientific challenge. His idea: to couple the creation of an original, global model of the evolution of Mars with new technological means. For this, he will benefit from an innovation developed within the LMD: the creation of a new "dynamic heart", an advanced computer that can accelerate the computing power of its model by several orders of magnitude.

With his team, he also benefits from the LMD’s exceptional technological network that gives access to the intermediate-sized computing centers of the IPSL and Sorbonne University. To accelerate IT processing, he also plans to use more powerful data centers that are coordinated at national and European level.

Thanks to these technological means and interdisciplinary collaborations, it will be able to integrate all the geological and topographical details of Mars available to scientists into a "new generation" model to show: the evolution of glaciers, rivers, lakes, the details of mountains, the effect of slopes and landforms and more.

"We can then accurately represent the evolution of the climate of Mars over millions of years and in very high resolution," says the researcher.

The number of scientific puzzles that astrophysicists will be able to address thanks to this new model is considerable. According to François Forget, there are dozens of applications. One of them would eventually use this tool to develop a "model of the evolution of the planets" and not only of Mars. In a few years, this capability may enable important scientific questions to be solved, such as whether extra-solar planets are habitable.

1 The LMD is jointly managed by Sorbonne University, CNRS, Ecole polytechnique, ENS and is a partner with Ecole des Ponts ParisTech. It is a member of the Pierre Simon Laplace Institute (IPSL).

2 Sorbonne University, CNRS, Ecole polytechnique, ENS.

3 A telluric planet, in oppose to the gaseous planets, is a planet composed mainly of rocks and metal, and its surface is solid.

4 An exoplanet, or extrasolar planet, is a planet outside the solar system.

5 LATMOS (Sorbonne University, CNRS, University of Versailles Saint-Quentin-en-Yvelines)