LECTURES BY CLIFFORD M. WILL

Popular Talks

Is Einstein Still Right? (also in French as Einstein, a-t-il toujours raison?)

How has the most celebrated scientific theory of the 20th century held up under the exacting scrutiny of planetary probes, radio telescopes, and atomic clocks? After 110 years, was Einstein right? In this lecture we relate the story of testing relativity, from the 1919 measurements of the bending of light to the 2015 detection of gravity waves and the 2019 images of black hole shadows. We will show how a revolution in astronomy and technology led to a renaissance of general relativity in the 1960s, and to a systematic program to try to verify its predictions. We will also demonstrate how relativity plays an important role in daily life.
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Black Holes, Waves of Gravity, and other Warped Ideas of Dr. Einstein (also in French as Trous noirs, vagues de gravité, et autres idées tordues de professeur Einstein)

Einstein's theories of relativity have had a major impact on everything from popular culture to everyday life to basic science. Songs, plays and movies proclaim Einstein as the symbol of genius, while users of GPS navigation devices unknowingly take account of Einstein's relativistic warpage of time. Two of the crazier ideas that come from Einstein's theories are Gravitational Waves and the Black Hole. Today, international teams of scientists are on a quest to verify these ideas. Using large-scale detectors on the ground they have detected Einstein's gravity waves and using world-wide arrays of radio-telescopes they have produdes images of supermassive black holes in distant galaxies. Gravitational waves provide a remarkable new tool for ``listening'' to Einstein's cosmic symphony.
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Colloquia/Seminars

Was Einstein Right?

Einstein formulated general relativity just over 100 years ago. Although it is generally considered a great triumph, the theory's early years were characterized by conceptual confusion, empirical uncertainties and a lack of relevance to ordinary physics. But in recent decades, a remarkably diverse set of precision experiments has established it as the "standard model" for gravitational physics. Yet it might not be the final word. We review a century of measurements that have verified general relativity, including the recent detections of gravitational waves, and describe some of the opportunities and challenges involved in testing Einstein’s great theory in new regimes of strong fields and gravitational radiation.
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The Renaissance of General Relativity

Einstein completed his monumental theory of General Relativity in 1915, and four years later became an international science superstar when astronomers announced that the Sun’s gravity bent light rays in agreement with his theory. Yet within a decade, interest and research in the theory declined, and by the late 1950s, people did not consider general relativity a suitable topic for a serious scientist to pursue. Yet 20 years later it had been reborn and had become one of the hottest fields of physics, with astronomers, particle physicists and experimentalists, once disdainful of the theory, now joining the fun. In this talk, I describe what happened to cause this renaissance, culminating in the stunning 1979 announcement by Joe Taylor of the detection of the inspiral of the orbit of the Binary Pulsar, caused by gravitational wave emission. I caught this rising relativistic wave in 1969 as a new student in Kip Thorne’s group at Caltech, and I will pepper the talk with personal experiences and encounters with many of the people who aided this rebirth.
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Lectures suitable for undergraduate physics students

The Search for Black Holes

One of the most remarkable predictions of Einstein's general theory of relativity is the Black Hole, a region of warped spacetime left over from the catastrophic collapse of a star from which nothing, not even light, can escape. What is a Black Hole and what are its properties? Do Black Holes really exist? Have gravitational-wave observatories recently given us the ``smoking gun'' for the existence of black holes?
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The Search for Gravity Waves

In 2015 a new form of astronomy began, called ``gravitational-wave astronomy''. General relativity predicts that moving matter produces gravitational radiation, and that the most intense sources of waves will be cosmic cataclysms such as the collapse of stars, or the collisions of black holes. In this lecture, we describe the nature and properties of gravitational waves, and the network of gravitational wave observatories that have recently detected these waves. Gravitational waves provide a remarkable new tool for ``listening'' to Einstein's cosmic symphony.
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