Cosmology and quantum physics both offer tantalizing possibilities that we inhabit just one reality among many. But testing that idea is challenging. More

At 3.3 billion light-years across, the ring may challenge the “cosmological principle” that the universe looks uniform at sufficiently large scales. More

Among the first finds from the Vera C. Rubin Observatory, the discovery hints at a population of exceptionally strong asteroids. More

The blast may have been a kilonova — a type of neutron star merger — in the wake of a more traditional supernova. More

The wake left by Betelgeuse’s companion could solve a decades-old mystery of its strange brightness cycles. More