Astrophysical consequences of extended cosmology

Abstract

Abstract. We outline astrophysical implications of a cosmological model based on the popular view that gravity should be extended from four to more dimensions to unify the forces of physics. At early times the model is inflationary, galaxies form easier, and their peculiar velocities are damped to produce a universal energy field. At late times the model is close to standard, but the dynamics of field galaxies and those in clusters are modified. It is possible to further test the model using a high-velocity radially-moving spacecraft in the solar system. These consequences provide a good way to look for extra dimensions.

Decaying dark energy in higher-dimensional gravity

“…It is important to recall here that standard cosmological models which are curved in 4D may be smoothly embedded in models which are flat in 5D. (For a review see the books by Wesson 1999Wesson , 2006, for an account of the embeddings from an astrophysical viewpoint see LachiezeRey 2000.) The data may therefore be suggesting not only that the universe has a fifth dimension, but that its structure may be much simpler than previously thought.…”

“…(3) to observation, we need to convert from proper time s to ordinary cosmic time t. A physicallymotivated argument due to Mashhoon is the following: translations along the -axis do not only introduce gauge-dependence into Λ; they also give rise to an apparent "fifth force" in the equations of motion (Mashhoon & Wesson 2004;Wesson 2005). This force can however be made to vanish by an appropriate choice of affine parameter, so making the motion geodesic in the usual 4D sense (Seahra & Wesson 2001).…”

An embedding for general relativity and its implications for new physics

“…Those readers who are more interested in physics than mathematics may like to proceed to Section 3, where we review our results and discuss their implications for new physics. These include changes in the cosmological "constant" and violations of the Weak Equivalence Principle, which may be tested using galaxies and artificial satellites [34,35]. In these and other ways, we can test if the world has more than four dimensions.…”

Astrophysics in 2006

“…The tests for extra dimension theories proposed by Wesson (2005) sound rather similar. There is also a possible test to separate dark energy from non-relativistic gravity from a scalar field from VWLS (Bertschinger 2006), but the least scalar 56 author cannot claim to understand it.…”