The Universe is a colossal web of invisible dark matter and galaxies, stretched by the expansion of space. Neutrinos, nearly intangible ghost particles, barely cling to the threads, but their collective mass subtly shifts the tension of the entire network.

Instead of bright nodes, scientists studied the voids between the strands. The shape of these "gaps" turned out to be highly sensitive to neutrino mass: heavier particles smooth out their edges. Using a method akin to unraveling a complex tapestry into individual stitches, researchers, even on a tiny patch of simulation (a cube half a billion light-years across), managed to estimate the neutrino mass with an error of 0.05 electronvolts — millions of times lighter than an electron.

Real sky surveys will allow us to check whether the Standard Model of physics is breaking down.