Betelgeuse—a gigantic star in the final stages of its life—has been acting weird lately, exhibiting dramatic drops in brightness. New research attributes enormous star spots to Betelgeuse’s flaky ...

Quasars, the luminous beacons at the centers of distant galaxies, have puzzled astronomers for decades with their dramatic brightness variations. Recent observations suggest that these celestial ...

Later this decade, the Large Hadron Collider will be upgraded to the High-Luminosity LHC. What does “luminosity” mean in particle physics? Even on the hottest and driest days, rays from the sun are ...