Topology and the Universe
Who: Berian James (DARK, Copenhagen)
When: Monday, October 26, 2009 at 14:15
Where: The CP³ meeting room
In recent decades, astronomical observations have led to a broad, if incomplete, consensus description of the large-scale Universe: its evolution is determined by a handful of substances (‘usual’ matter like atoms, stars and galaxies; a hidden, but gravitationally attractive dark matter; the poorly understood and unfortunately named dark energy) all of which are changing under the influence of physical laws. In the region of the Universe visible to astronomers, great cosmological structures are observed—dense clusters in which the majority of galaxies form; vast and apparently empty voids; and a tangle of filaments that has been coined ‘the cosmic web’.
In this talk, I explore the role that topology, the mathematics of shape, plays in defining our understanding of the Universe. After reviewing the relationship between geometry and dynamics that characterises the modern Big Bang theory, I discuss three topics of broad scope: i) the classification of cosmological structures as a means of understanding both the physics of the very early Universe and the evolution and formation of galaxies; ii) the impact of some modern mathematical results from differential geometry that have yet to be fully assimilated into physics; and iii) the theory and measurements of the global topology of the Universe—does it extend infinitely in all directions, or wrap-around on itself, and how can we tell?
Due to technical reasons the first few minutes of the talk are unfortunately missing from the recording.