Subjects
Physics
Research Interests
I work on the formation and structure of galaxies. The present structure of a galaxy is intimately connected with how the galaxy formed because galaxies are slow-moving beasts - it takes 200,000,000 years for the Sun to rotate once about the galactic centre. So galaxies evolve slowly. Moreover, unlike a cup of hot tea, a galaxy lacks an equilibrium state to which it can relax: it's doomed to move on for ever, never to arrive.
4/5 of the matter in the Universe is supposed to be contained in unknown dark-matter particles. The gravitational field generated by this dark matter influences the dynamics of the stars and gas that we can study. By developing novel techniques for dynamical modelling, my group probes the distribution of dark matter within and around galaxies. This is a golden age of astronomical surveys, and we are struggling to exploit colours and radial velocities of hundreds of thousands of Milky-Way stars that are constantly being released. Another important line of evidence is the frequency of gravitational-microlensing events.
We are working towards the time in the next decade when the European Space Agency releases data for a billion stars measured by its Gaia satellite. The hope is that these data will make it possible not only to trace the distribution of dark matter in detail, but also to deduce how the Milky Way formed.
Our interest in galaxy formation has led to work on how active galactic nuclei (AGN) heat "cooling flows" - vast reservoirs of gas at in excess of ten million degrees that fill all the deeper potential wells in the Universe. In the 1990s we argued that cooling flows neither cool nor flow because they are intermittently heated by AGN. Observations made by two X-ray observatories have vindicated this view. More recently I have been arguing that the ability of AGN to stabilise cooling flows requires a fundamental revision of the conventional picture of galaxy formation.
Teaching
Over the years I have taught a wide range of topics in physics and mathematics. I've coauthored a 2-volume graduate text on galaxies and an introduction to the theory of critical phenomena (two of the other three authors of this book were former Merton undergraduates). Another former Merton undergraduate and I have an introductory text on quantum mechanics in an advanced state of preparation. I believe physics should be defined as the mathematical description of phenomena, and that it is the core science. It is useful and it changes your understanding of what material reality is. I want nothing so much as to help others to understand the subject's power and range.
Department Information
Contact Information
Personal Website: James Binney
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