Weekly seminars

From precision to accuracy; the universe observed on different scales (remote talk)

by Julien Larena (UCT )

Auditorium Vivargent (LAPTh)

Auditorium Vivargent


9, chemin de Bellevue 74000 ANNECY
Cosmology has entered an era of unprecedented precision. With measurements of the fluctuations in the cosmic microwave background radiation, their counterparts in large-scale structure in the form of baryon acoustic oscillations and the development of the cosmic distance ladder, the concordance model of cosmology is established as a robust standard model, able to describe the universe from seconds after the Big Bang to today and on spatial scales ranging from galaxies to the entire visible universe. The values of its free parameters are now pinned down to remarkable precision and future galaxy surveys will allow further improvement in precision.
However, with growing precision, some tensions have started to emerge. Although it is tempting to attribute these growing tensions to signs of new, exciting physics, it is important to make sure that our cosmological model is accurate on top of being precise; that is, to ensure that these tensions are not, in part or completely, systematic offsets due to our imperfect modeling of a complex, multi-scale system.
In this talk, I will present some tests of the accuracy of our standard model, focusing on some central assumptions of the model and addressing in particular: the geometry of the very large-scale universe, the propagation of light in an inhomogeneous universe, and ways to probe the small scale distribution of matter.