Found 12 talks width keyword gravitation

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Tuesday March 23, 2010
Origin of space and time in a non-commutative cosmological model
Vatican Observatory, Italy

Abstract

A Friedman-like cosmological model, based on noncommutative geometry, is presented. Its Planck level is totally nonlocal with no space and no time. The dynamics on this level is strongly probabilistic which makes the initial singularity statistically insignificant. Space, time and the standard dynamics emerge when one goes from the non-commutative regime (on the Planck level) to the usual "commutative physics".
Archived in: Cosmology - Keywords:gravitation, early universe, distance scale
Abstract


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Thursday February 19, 2009
Cosmology on small scales: the structure of (mostly) dark matter halos
Institute for Computational Cosmology, Physics Dept, Durham University

Abstract

The standard model of cosmology -- the ``Lambda cold dark matter'' model -- is based on the idea that the dark matter is a collisionless elementary particle, probably a supersymmetric particle. This model (which mostly dates back to an early workshop in Santa Barbara in the 1980s) has been famously verified by observations of the cosmic microwave background radiation and the large-scale distribution of galaxies. However, the model has yet to be tested conclusively on the small scales appropriate to most astronomical objects, such as galaxies and clusters. I will review our current understanding of the distribution of dark matter on small scales which derives largely from large cosmological N-body simulations and I will discuss prospects for detecting dark matter, either through its gravitational effect on galaxies and clusters or, more directly, through gamma-ray annihilation radiation.
Archived in: Cosmology - Keywords:fundamental physics, distance scale, dark matter, cold dark matter, CMB, gravitation, n-body simulations
Abstract


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