Gravitational Waves : Theory, Sources and Detections (2/2)
Department Lecture

Alexandre Le Tiec (LUTh, Observatoire de Paris) — September 15 and September 22, 2016

This Seminar is the second part of the yearly Department Lecture
The first part is accessible here.

Abstract :
A century ago, Albert Einstein revolutionized our understanding of the nature of space, time and gravitation. His general theory of relativity predicts, in particular, the existence of black holes and gravitational waves. By sheer coincidence, the celebration of general relativity’s centennial also marked the first-ever observation, by the two ground-based LIGO interferometers, of gravitational waves emitted during the coalescence of two stellar-mass black holes. This was the first direct detection of gravitational waves, but also the first direct evidence for the existence of black holes.

This two-part lecture will provide an introduction to the blossoming field of gravitational-wave science. The first part of the lecture will address the following questions : what are gravitational waves ? How do they differ from electromagnetic waves ? How are they generated ? What are the expected astrophysical sources ? The second part of the lecture will explore the topic of gravitational wave detection : how do gravitational waves interact with matter ? What are the existing and future gravitational-wave detectors ? Finally, we will describe the key features of the two gravitational-wave signals detected during the fall of 2015, and explain how physicists can infer the nature of their sources and measure some of their physical properties.

Biography :
Dr. Alexandre Le Tiec is a CNRS Junior Research Scientist working at the "Laboratoire Univers et Théories" of the Paris Observatory. His research interests include black holes, gravitational waves and dark matter. He has been awarded the Chandrasekhar Prize of the International Society on General Relativity and Gravitation. He teaches General Relativity to second-year Master’s students at the Paris Observatory.

You can also watch this video on savoirs.ens.fr