Web page of: Håkan Andréasson University of Gothenburg Chalmers University of Technology Department of Mathematics S-412 96 Göteborg Sweden Room:          L2037 Telephone:   +46 (0)31 772 53 30 E-mail:        hand@chalmers.se   Disclaimer: This is a personal web page

This Hubble Space Telescope image contains three main features. The outer white area is the core or centre of the galaxy NGC4261. Inside the core there is a brown spiral-shaped disk. It weighs one hundred thousand times as much as our sun. Because it is rotating one can measure the radii and speed of its constituents, and hence weigh the object at its centre. This object is about as large as our solar system, but weighs 1,200,000,000 times as much as our sun. This means that gravity is about one million times as strong as on the sun. Almost certainly this object is a black hole.

1915 Einstein published his celebrated work on the theory of gravitation, general relativity. A remarkable feature of Einstein's equations, which describe the effect that matter has on the curvature of spacetime, is the prediction of black holes in our universe. Einstein's equations constitute a system of nonlinear partial differential equations. The available mathematical results for this system are rather sparse and there is a large number of open and important mathematical problems in this field. To read more about my interest in general relativity click on research.