Gravitational lensing: "Einstein's Unfinished Symphony"

About the speaker

Richard Ellis is the Steele Professor of Astronomy at the California Institute of Technology and holds a Royal Society Research Professorship at the University of Oxford. His research is concerned with the use of supernovae, large scale structure and weak gravitational lensing as probes of the cosmological model and the nature of dark energy. He also uses the 10 meter Keck telescopes in conjunction with Hubble and Spitzer Space Telescopes to chart the mass assembly history of galaxies.

The Niels Bohr Lectures and Niels Bohr Institute Colloquia is a lecture series in English language directed at students and staff at the Niels Bohr Institute and other interested parties. The lectures are held by some of the world's leading scientists and by the staff of the Institute. They are held at a technical level corresponding to a background similar to the first few years of the physics education.

Abstract

Gravitational lensing, the bending of light beams by foreground mass structures, was recognized as an important feature of Einstein's theory of relativity and verified at the time of a solar eclipse in 1919. However, only in the last 20 years has it become apparent how useful the phenomenon can be to the cosmologist. Gravitational lensing holds great promise as a means for charting the distribution of dark matter on various scales and in understanding its growth with time. Certain cosmic lenses can also enlarge and brighten distant objects enabling astronomers to gain additional information on the early Universe.