"The Contribution of Planck to Cosmology"
Graca Rocha (Jet Propulsion Laboratory at Caltech)
340 West Hall on Thursday, April 18 from 3-4 pm
On 21st of March of 2013, the ESA, NASA and the Planck collaboration announced the first cosmological results together with the data delivery and twenty eight scientific papers. This talk will give an overview of the main cosmological results from Planck presented in these twenty eight papers. The Planck satellite unveiled the most detailed and accurate map of the cosmic microwave background (CMB) --- the relic radiation from the Big Bang. Planck data confirms that the Universe is well described by a simple model in that it is fully defined by six key cosmological parameters. The Universe is older than expected, is expanding more slowly, has more dark matter and less dark energy than previously thought. Furthermore Planck puts stringent constraints on several models of Inflation (a period of exponential expansion of the Universe). With Planck data there is no evidence so far for a dynamical dark energy; no evidence for new types of ultralight particles such as neutrinos; no evidence for time-variation of fundamental constants such as 'fine-structure constant'; it also sets upper limits in the tensor-to-scalar ratio and finds that the fluctuations in the temperature of the CMB are very random (Gaussian). Some peculiar features 'anomalies' are observed in Planck maps, including the 'cold spot' (a spot extending over a patch of sky that is larger than expected) and the hemispherical asymmetry (i.e the two halves of the sky look different). These feature are unexpected in the context of the standard model.