C/1865 B1

The comet NEOWISE seen over Nevada in 2020.Image: Ethan Miller (Getty Images)An incoming comet recently spotted by telescopes in China and South Africa could be as bright as a planet in the night sky next year, according to astronomers who studied the object.The comet—an accumulation of rock, dust, and ice—is called C/2023 A3 (Tsuchinshan-ATLAS). It was discovered by astronomers at the Purple Mountain Observatory in China in Januaryand subsequently by the Asteroid Terrestrial-Impact Last Alert System (ATLAS) on February…

Deep in the Stone Age, when Neanderthals still lived alongside Homo sapiens, our ancestors might have been agog at a green light in the night sky. Now, that light—C/2022 E3 (ZTF) (more familiarly, the Green Comet)—is back.The Green Comet’s highly elliptical orbit means it will take a long time for it to swing past Earth again—about 50,000 years, to be specific. And that’s if it repeats its 50,000-year sojourn, which it may not.Astronomers discovered the comet in March 2022 using the Samuel Oschin robotic telescope at the…