Jupiter’s atmosphere consists predominantly of molecular hydrogen and helium with small fractions of other compounds such as water. Powerful storms are believed to occur on Jupiter as a result of moist atmospheric convection coupled with the evaporation and condensation of that water. Previous outer planetary missions observing Jupiter, such as Voyager, Galileo, and New Horizons, have detected lightning flashes within the water clouds of its atmosphere. However, imagery capturing lightning storms from these missions has been limited by spatial resolution due to the sensitivity of their cameras, camera exposure time, and their distance from Jupiter.
NASA’s New Frontiers’ Juno spacecraft was launched on August 5, 2011, and has been orbiting Jupiter since 2016. A recent study led by Heidi Becker from NASA’s Jet Propulsion Laboratory (California Institute of Technology) reports optical observations from Juno’s Stellar Reference Unit (SRU) imager. Usually the role of the SRU imager is for detection of dim stars, which assists the spacecraft with positioning and navigation. Now, it has found an additional scientific use: detecting lightning on Jupiter at higher resolution than ever before. During flybys of Jupiter’s dark side, the SRU imager detected small, shallow, and very frequent flashes of lightning that have optical energies similar to lightning that is observed on Earth. Some of these small flashes must originate from above the altitude where liquid water is found in the Jovian atmosphere, suggesting more than one mechanism produces the lightning flashes on Jupiter. READ MORE