Professor Geraint Lewis is Professor of Astrophysics in the School of Physics at the University of Sydney, where he is also affiliated with the Sydney Institute for Astronomy and heads the Gravitational Astrophysics Group. He obtained his BSc (Hons) in Physics and Astronomy from Queen Mary College, University of London in 1990, PhD in Astronomy from the Institute of Astronomy at the University of Cambridge in 1995, and Graduate Certificate of Higher Education from the University of Sydney in 2003. After postdoctoral research at the University of Cambridge (1996–1997) and the University of Victoria in Canada (1997–1999), he joined the University of Sydney in 2002. He has held positions including Associate Head for Research in the School of Physics and Deputy Director of the Sydney Informatics Hub until 2020, and was an Australian Research Council Future Fellow from 2011 to 2015.

Lewis pursues a wide-ranging research program in astrophysics, examining the roles of dark energy and dark matter in shaping the Universe's evolution and destiny. He employs gravitational lensing to investigate dark matter structures in galaxies and to magnify distant quasars via stellar microlensing. His studies also encompass galactic cannibalism, tracking tidal disruptions of dwarf galaxies by the Milky Way and Andromeda using observations from the Keck telescope and others. With over 44,000 citations on Google Scholar, his contributions have profoundly influenced cosmology, extragalactic astronomy, and gravitational physics. Notable publications include the books A Fortunate Universe: Life in a Finely Tuned Cosmos (2016, co-authored with Luke A. Barnes), The Cosmic Revolutionary's Handbook: Or How to Beat the Big Bang (2020, with Barnes), and Where Did the Universe Come From? And Other Cosmic Questions (2021, with Chris Ferrie). Lewis has received the Walter Boas Medal (2016), David Allen Prize (Astronomical Society of Australia, 2021), and fellowships from the Learned Society of Wales (2020) and the Royal Society of New South Wales.

Professional Email: geraint.lewis@sydney.edu.au