Lecture: “The Mystery of Dark Matter in the Universe”

Thursday, January 18, 2018, at 8:00 p.m.
Galileo Planetarium
By Julien Lavalle, a researcher at the CNRS and a theoretical physicist at the Montpellier Universe and Particles Laboratory (LUPM).
With the considerable advances in modern physics—both theoretical and observational—it is now possible to have a coherent picture of the cosmos at nearly every scale, from the infinitely small to the infinitely large—that is, from the scale of elementary particles to that of the Universe as a whole. The precision of recent measurements in cosmology allows us to determine the energy balance of the universe. In particular, it has been established that our universe is “flat,” that its expansion is accelerating, and that matter consists overwhelmingly (85%) of an unknown component that is invisible and interacts only gravitationally (or almost exclusively so) with the ordinary matter that characterizes our observable environment. The acceleration of expansion manifests as a repulsive force known as “dark energy,” while the unknown matter component has been given the equally unsettling nickname “dark matter.”
Do these strange words mean that the sky is going to fall on our heads? Is the 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 topic of dark matter, seeking to demonstrate how it affects all macroscopic scales of the universe—from the scale of galaxies to the scale of the cosmos—and how it is, in fact, essential to our understanding of galaxy formation.
He will explain how this cosmological and astrophysical puzzle may 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 both directly and indirectly, using telescopes as well as particle accelerators.
The observational net is gradually closing in on the most promising theoretical solutions thanks to a multitude of complementary international experiments in this field, and a large portion of these solutions will either be confirmed or ruled out in the coming decades.
This lecture will begin with a screening of the film “Ghost of the Universe: The Hunt for Dark Matter” on the Planetarium’s dome.
Free Admission with reservation by email by providing your last name, first name, email address, and phone number.
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