Reference Frame/Coordinate System in General Relativity

Prediction in general relativity

Several authors have claimed that prediction is essentially impossible in the general theory of relativity, the case being particularly strong, it is said, when one fully considers the epistemic predicament of the observer. Each of these claims rests on the support of an underdetermination argument and a particular interpretation of the concept of prediction. I argue that these underdeterminati...

Astrometric tests of General Relativity in the Solar system

Micro-arcsec astronomy is able to verify the predictions of theoretical models of gravitation at a level adequate to constraint relevant parameters and select among different formulations. In particular, this concerns the weak field limit applicable to the Sun neighborhood, where competing models can be expressed in a common framework as the Parametrised Post-Newtonian and Parametrised Post-Pos...

2 Analysis of a Shell System in General Relativity

General-relativistic Visualization General Relativity

I n our previous article about special-relativistic visualization,1 we described what the travelers from our highly developed civilization observed when they passed the Earth; now, they set out for the Cygnus X-1 binary system, which is roughly 6,000 light years away. The Cygnus X-1 system consists of a super giant variable star (HDE 226868) and a very compact object—presumably a black hole—wit...

Topology Change in General Relativity∗

A review is given of recent work on topology changing solutions to the first order form of general relativity. These solutions have metrics which are smooth everywhere, invertible almost everywhere, and have bounded curvature. The importance of considering degenerate metrics is discussed, and the possibility that quantum effects can suppress topology change is briefly examined. * To appear in t...