"Cosmic flows and weak gravitational lensing crank up the tension in cosmology"

The now-well-known "Hubble tension" is the difference between the expansion rate measured locally and that predicted from Cosmic Microwave Background (CMB) measurements extrapolated to the present-day assuming the Lambda Cold Dark Matter cosmological model. Similar, but less well known, is the "S8 tension" which is related to the smoothness of the Universe. This tension is most strongly felt comparing recent weak gravitational lensing measurements to the CMB. The same S8 tension is also present when using other probes of the homogeneity of the nearby Universe. In particular, peculiar velocities - deviations from Hubble expansion - probe the growth rate of matter density fluctuations on large scales. I will discuss recent measurements of cosmological parameters based on our approach of predicting peculiar velocities from the density field. Time permitting, I will also describe results from our new weak lensing survey, the Ultraviolet Near-Infrared Optical Northern Survey (UNIONS), which should have an impact on this topic.