Archive for December, 2006

An excellent letter to the editor from this month’s issue of Symmetry Magazine: Reading your September issue of symmetry, I was reminded of when Larry Rosenson of MIT told me the story some years ago of being stuck on a long flight next to a talkative woman. She insisted on telling him how great her […]


The operating principle of theoretical physics in the past half century has been symmetry. The language of this operating principle is group theory. An abstract mathematical group acts linearly on a set of particles as a ‘representation’ of that group. Faithful representations preserve the subtleties of the abstract group. (Semi-simple groups are reducible, i.e. they […]


One highlight of this past term has been the opportunity to give a seminar talk on a topic of one’s choice. The purpose of this ‘Part III seminar series‘ is for students to develop skills necessary for presenting ideas in an academic talk. The general suggestion was to take an idea related to a course […]


There’s something that’s been on my mind for over a year now. The angle of the wake of a duck moving with constant velocity in deep water is independent of the velocity of the duck (~39 degrees).  Why is this? (This makes me regret not sitting in on the Part II fluid dynamics course this […]