Talk abstract details

The Universe as we observe it is very inhomogeneous. Among the structures in the Universe there are groups and clusters of galaxies, large cosmic voids and very large elongated structures. However, cosmological observations such as those of supernovae or cosmic microwave background (CMB) are usually analysed against homogeneous models, which are taken for granted. In my talk I will present the analysis of the supernova and CMB observations against the background of exact inhomogeneous models, those of Lemaitre--Tolman and Szekeres. In these models, light propagation and matter evolution can be calculated exactly, without such approximations as small amplitude of the density contrast. This will allow us to check if such features of standard cosmology like cosmological constant or dark energy are real, or they are just manifestations of matter being not homogeneously distributed.