Meeting with two eminent astrophysicists “made in Saint-Tropez”

Open Friday afternoon to college students, by Roland Leboucq, astrophysicist at the CEA and author of the book “Where do Superman’s powers come from?”, and continued for the general public by the very brilliant Françoise Combes, astrophysicist member of the Académie des Sciences, the “Scientific Meetings” will end on Sunday morning with the intervention, Salle Despas, from 10 a.m. to noon, by Anne Lagrange.

*Major players in these “Scientific Meetings 2022”, the two astrophysicists from Saint-Tropez Patrick Michel, director of research at the CNRS, project manager at the UN for various programs, and Sacha Brun, director of research at the CEA, moderated Saturday, room Jean-Despas, two conference-debates, with their colleagues mentioned above, on the formation and evolution of stars, as well as the formation of the solar system. Maintenance.

What do we know about the subject compared to what remains to be known?

Sasha Brown: In fact, we don’t know! Because the more we discover, the more we open up other fields of discovery and the more we become aware of our lack of knowledge.

patrick michael: On the other hand, what is positive about the laws of physics and astrophysics is that no observer contradicts them. They are validated under the conditions in which they were accessed.

How do stars form and how do they evolve?

S.B: Simplifying, a star is formed by the collapse of a gas on itself, which allows it to shine. The Sun is the star of our so-called solar system, but there are billions of them in the universe. Which doesn’t mean there are other planets or exoplanets like ours with life.

P.M: Afterwards, always to simplify, the planets are, originally, bodies which revolve in orbit around their star. It’s not forever: our solar system will disappear in about 4 to 6 billion years, because a star, like the sun, only shines because it has fuel. When this fuel is exhausted, there will be no more sun, no more solar system and therefore no more life on planet Earth. You won’t see it and neither will I.

What major works are you currently carrying out?

S.B : I’m working on a difficult subject that humans might worry about because it concerns major meteorological risks: space weather. How to live around a star according to this weather parameter? Which involves me in another more technical area: the development of computers capable of performing billions of billions of calculations in a second.

P.M: I worked with the UN, most recently, on the deflection of an asteroid by a satellite, a successful operation. We will now collect samples from this asteroid and study them. I am also working on samples from Phobos, one of the two satellites of Mars, to find out its origin.