Modern Cosmology .........2008
by Michael J. Disney
Biography
Michael J. Disney is emeritus professor in the School of Physics and Astronomy at Cardiff University. He has done research on stars, pulsars and quasars, but his main interest has always lain in galaxies and in designing novel instruments to observe them at many wavelengths. He has worked on the development of Hubble Space Telescope instruments since 1976.
The Significance of Cosmology:
The currently fashionable concordance model of cosmology (also known to the cognoscenti as "Lambda-Cold Dark Matter," or lambda-CDM) has 18 parameters, 17 of which are independent. Thirteen of these parameters are well fitted to the observational data; the other four remain floating. This situation is very far from healthy. Any theory with more free parameters than relevant observations has little to recommend it...
The three successful predictions of the concordance model (the apparent flatness of space, the abundances of the light elements and the maximum ages of the oldest star clusters) are overwhelmed by at least half a dozen unpredicted surprises, including dark matter and dark energy. Worse still, there is no sign of a systematic improvement in the net significance of cosmological theories over time.
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Where Do We Stand Today?
Big Bang cosmology is not a single theory; rather, it is five separate theories constructed on top of one another. The ground floor is a theory, historically but not fundamentally rooted in general relativity..............
In its original form, an expanding Einstein model had an attractive, economic elegance. Alas, it has since run into serious difficulties, which have been cured only by sticking on some ugly bandages: inflation to cover horizon and flatness problems; overwhelming amounts of dark matter to provide internal structure; and dark energy, whatever that might be, to explain the seemingly recent acceleration. A skeptic is entitled to feel that a negative significance, after so much time, effort and trimming, is nothing more than one would expect of a folktale constantly re-edited to fit inconvenient new observations...
The historian of science Daniel Boorstin once remarked: "The great obstacle to discovering the shape of the Earth, the continents and the oceans was not ignorance but the illusion of knowledge. Imagination drew in bold strokes, instantly serving hopes and fears, while knowledge advanced by slow increments and contradictory witnesses." Acceptance of the current myth, if myth it is, could likewise hold up progress in cosmology for generations to come.