According to Einstein’s theory of gravity, the universe should be expanding and forming structures such as galaxies and clusters of galaxies following concrete rules that depend on the composition of those galaxies and on the matter and energy that fills the space among them. Observing the universe we can thus compare theory with facts. And we are having a difficult time reconciling theoretical expectations with reality because different measurements of the same thing yield different values. Like two builders disagreeing on the size of a door. If new tensions arise in other measurements, the whole construction could be in danger.
The existence of growing discrepancies between data obtained by different teams is causing tensions in the current cosmological model, which requires a dedicated effort to figure out their origin. Could they be due to how observational data are obtained? Or to how they are analysed? Or is it a problem of the theoretical model used to interpret the data? Bringing together experts in these three complementary aspects, we aim at making progress on the important open question of tensions in cosmology.