‘Exotic’ lightning crackles across Jupiter’s cloud tops
Small, frequent lightning storms zip across Jupiter’s cloud tops. NASA’s Juno spacecraft spotted the flashes for the first time, scientists report August 5 in Nature. “It’s a very exotic thing that doesn’t exist on Earth,” says physicist Heidi Becker of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Previous spacecraft have revealed high-energy “superbolts” on Jupiter. That lightning originates 50 to 65 kilometers below Jupiter’s cloud tops, where liquid water droplets form. Scientists think superbolts form like lightning on Earth does: Colliding ice crystals and water droplets charge each other up, then stretch the charge between them when they separate (SN: 6/25/20). Juno, which arrived at Jupiter in 2016, got much closer to the giant planet’s cloud tops than previous missions. Becker and her team turned the spacecraft’s navigation camera — which normally observes stars to track Juno’s position — on Jupiter’s nightside in February 2018. To the team’s surprise, the clouds crackled with...