Gravity on the largest scales: Do we need to go beyond Einstein?
Tuesday 13 September 2016
to 14:00 at
Yashar Akrami (University of Leiden)
Despite its continued observational successes, there is a persistent (and growing) interest in extending cosmology beyond the standard model. This is motivated by a range of apparently serious theoretical issues, as well as the existence of various anomalies in the cosmological data. In particular, many think that general relativity (GR) as one of the pillars of our cosmological model, despite its striking success in describing various astrophysical phenomena, is not the ultimate theory of gravity, and one needs to go beyond Einstein's incredible theory on extreme scales. It is of significant importance to study gravity in cosmology, and any progress in this direction will provide invaluable knowledge about the properties of the Universe on the largest scales, right after its birth, at present, and in the future. Several alternative theories of gravity on the largest scales have been proposed over the last 15 years, although it is not easy to come up with proposals that are theoretically well motivated, mathematically consistent, and observationally viable. While the efforts for building new theories continue, various techniques are being developed for testing them, as well as GR itself, and several future cosmological surveys are expected to help us pin down the nature of gravity. The study of alternative cosmologies so far has led to considerable progress, with much more to come if hopes about forthcoming high-precision observations and new theoretical ideas are fulfilled. We are living at an extremely exciting moment in the history of cosmology and fundamental physics, and hopefully we will soon be able to exclude either our standard picture or most of its alternatives.
(host: Edvard Mörtsell)