Comet NEOWISE Will Come Back in 6,800 Years

NASA’s space telescope, the Near-Earth Object Wide-field Infrared Survey Explorer, or NEOWISE, spotted a comet back in March. Comet NEOWISE is 4.6 billion years old, about 3 miles across, and has a long tail. It’s best visible with the naked eye in the Northern Hemisphere, about an hour and a half after sunset, for several weeks.