NUMERICAL APPROACH TO THE GLOBAL STRUCTURE OF SPACETIMES

In most approaches to numerical relativity it is very difficult to det ermine global properties of spacetimes since typically only finite reg ions of spacetime are evaluated. But global properties are of major in terest for many fields of general relativity, e.g. cosmic censorship ( existence and location of event horizons) and gravitational radiation (whose definition and determination requires knowledge of the geometry at null infinity). In this talk I will briefly outline an approach us ing conformal techniques to calculate global properties. The advantage s of this method are demonstrated using two examples, the determinatio n of event horizons and the decay of radiation. The calculations have been performed with a spherically symmetric spacetime using a conforma l scalar field as radiation and matter model.