Editorial note to : Jerome Kristian and Rainer K . Sachs , Observations in cosmology
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چکیده
This paper is one of the least appreciated fundamental papers in theoretical cosmology. It carefully develops a direct observationally based approach to cosmology, in contrast to the standard model-fitting approach; and it does so in a comprehensive and systematic way. However it only does so in the form of a power-series solution (as was the custom at the time in cosmology): later papers have taken the approach further. The basic issue is that there is an ongoing tension in cosmology between theory and observation. Theoretical models have given us major insights into the nature of processes taking place, but have of necessity utilized very simple geometrical models of spacetime and the matter distribution in it. Indeed the standard theory of cosmology is based on highly simplified models: the spatially homogeneous and isotropic Robertson-Walker (RW) family of spacetimes, distinguished from each other by the values of a few parameters to be observationally determined by astronomical observations. These basic models are then modified to perturbed RWmodels that statistically represent the kinds of inhomogeneities seen. The statistics of these models are fitted to the actual observations, and then used to constrain theories of structure formation and background evolution, hence putting further constraints on the background model
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تاریخ انتشار 2010