Press release  ·  UNIONS  ·  July 2026

The largest dark matter map
of the northern sky

Ten years of imaging the northern sky, and the shapes of 61 million distant galaxies across 3,500 square degrees. Where their light passes mass on the way to us it is bent, and their shapes are distorted by a fraction of a per cent — which is enough, over 61 million of them, to weigh what lies in between. The blue is that mass. I am a member of the collaboration and work on its weak lensing.

Visualisation: Calum Murray, Cail Daley and Andreas Tersenov. Sky background: ESA/Gaia/DPAC. Imaging from the Canada–France–Hawaii Telescope, Pan-STARRS and Subaru.