Conference: “The Enigma of Dark Matter in the Universe”

Thursday, January 18, 2018, at 8 p.m.
Galileo Planetarium
By Julien Lavalle, researcher at the CNRS, theoretical physicist at the Montpellier Universe and Particles Laboratory (LUPM).
With the considerable developments in modern physics, both theoretical and observational, it is now possible to have a coherent representation of the cosmos at almost all scales, from the infinitely small to the infinitely large, i.e., from the scale of elementary particles to that of the Universe as a whole. The precision of recent measurements in cosmology has made it possible to draw up an energy balance for the Universe. In particular, it has been established that our universe is "flat," that its expansion is accelerating, and that matter is overwhelmingly composed of an unknown (85%) and invisible component that interacts only gravitationally (or almost) with the ordinary matter that characterizes our intelligible environment. The acceleration of expansion manifests itself as a repulsive force known as "dark energy," while the unknown component of matter has been given the equally disturbing nickname of "dark matter."
Do these strange words mean that the sky is falling on our heads? Is Star Wars about to begin? Of course not! They simply tell us that most of the universe still eludes our understanding, at least for now...
During this lecture, Julien Lavalle will focus on the question of dark matter, attempting to show how it affects all macroscopic scales of the Universe, from the scale of galaxies to the scale of the cosmos, and how it proves to be indispensable to our understanding of galaxy formation.
He will show how this cosmological and astrophysical enigma can be solved by the physics of the infinitely small (in the form of new elementary particles), what theoretical avenues are currently being explored, and how the signatures of these hypothetical particles are being sought directly and indirectly, using both telescopes and particle accelerators.
The observational vise is gradually tightening around the most promising theoretical solutions thanks to a multitude of complementary international experiments operating in this field, and many of these solutions will either be confirmed or ruled out in the coming decades.
This lecture will be introduced by a screening of the film "Ghost of the Universe – The Hunt for Dark Matter" on the dome of the Planetarium.
Free admission upon reservation by email by leaving your last name, first name, email address, and phone number.
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