Speaker:Prof. Gary Gibbons (DAMTP)
Venue: Old Combination Room, Trinity College
Time: 04/02/2008 20:30, drinks from 20:15

The talk is available.

If we take light rays as straight lines, and if light is bent by a gravitational field, then the angular sum of a triangle cannot equal 180 degrees. In this talk I will use the Gauss-Bonnet theorem to discuss the angular sum of triangles in the vicinity of black holes, and elsewhere in the universe.