Testing basic laws of gravitation - Are our postulates on dynamics and gravitation supported by experimental evidence?

Abstract

Gravity is the most fundamental interaction; it not only describes a particular interaction between matter, but also encompasses issues such as the notion of space and time, the role of the observer, and the relativistic measurement process. Gravity is geometry and, in consequence, allows the existence of horizons and black holes, nontrivial topologies, a cosmological big bang, time-travel, warp drive, and other phenomena unknown in nonrelativistic physics. Here we present the experimental basis of General Relativity, addressing its foundations encoded in the Einstein Equivalence Principle and its predictions in the weak and strong gravity regimes. We discuss several approaches in the search to reveal an influence of the much sought-after quantum theory of gravity. We emphasize assumptions underlying the dynamics - for example, Newton's axioms and conservation laws - and the current extent to which they are supported by experiment. We discuss conditions under which gravity can be transformed away locally, and examine higher order time derivatives in the equations of motion. © 2011 Springer Science+Business Media B.V.