Freiburg 2008 – wissenschaftliches Programm

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GR: Fachverband Gravitation und Relativitätstheorie

GR 2: Alternative klassische Gravitationstheorien

GR 2.1: Vortrag

Montag, 3. März 2008, 18:25–18:45, KGI-HS 1010

A New Look at the Contributions to Cosmology of Dirac, Sciama and Dicke — •Alexander Unzicker — Pestalozzi-Gymnasium München

Though the separate contributions to cosmology of the above named researchers seem abandoned today, surprisingly their basic ideas can be encompassed into a consistent framework. We study Dirac's large number hypothesis (Proc.Roy.Soc. Lon. A 165, 199; 1938), Sciama's proposal of realizing Mach's principle (MNRAS 113, 34; 1953), and Dicke's considerations on an `electromagnetic' theory of gravitation with a variable speed of light (Rev.Mod.Phys. 29, 363; 1957). Dicke's tentative theory can be formulated in a way which is compatible with Sciama's hypothesis on the gravitational constant G. Additionally, such a gravitational model satisfies Dirac's large number hypothesis without entailing a visible time dependence predicted by Dirac which indeed has never been verified. While Dicke's proposal, similarly to well-known flat space representations of general relativity (e.g. Dehnen et al., Ann.Phys. 6 (Folge 7),370; 1960) in first approximation agrees with the four classical tests, the cosmological redshift arises from a shortening of measuring rods rather than from an expansion of space.