A comet is currently brightening faster than expected, giving hope that it will become a prominent object visible with the unaided eye in May. An image of Comet C/2019 ATLAS taken from Walmer, Kent, UK, on March 12th, 2020. Image credit: Paul Sutherland The celestial visitor is labelled C/2019 Y4 ATLAS, indicating that it was discovered in 2019 by a sky survey called the Asteroid Terrestrial-impact Last Alert System (ATLAS). This robotic survey, based in Hawaii, searches for small objects to help defend Earth against possible future impacts, and has found several comets as well as asteroids. Comet C/2019 Y4...