St John's College Oxford
Dr Harry Desmond

Dr Harry Desmond

Junior Research Fellow in Physics


I am a theoretical cosmologist at the Beecroft Institute for Particle Astrophysics and Cosmology. I received my PhD from Stanford and my MPhys from Oxford.

Research Interests

I study the morphology and dynamics of galaxies to learn about the constituents and evolution of the universe. I'm particularly interested in using measurements of galaxies to tackle two key questions in cosmology. First is the identity and phenomenology of "dark matter", a mysterious substance which dominates the universe's mass budget but doesn't emit light and hence can't be seen directly. The connection between normal and dark matter is manifest observationally in the relations between galaxies' luminosities and internal motions, which I investigate in statistical detail. Second is the nature of gravity. Despite extensive testing in the Solar System and on Earth, the reigning theory of gravity -- Einstein's General Relativity -- has not received direct corroboration on larger scales. I devise and carry out novel tests of gravity in galaxies, as well as exploring more generally the galaxy-scale consequences of modified gravity theories.

I pursue these topics with a combination of pen-and-paper theory, model building, galaxy survey data, cosmological simulations and bewilderment.