On Dec. 11, 2016, NASA’s Juno spacecraft successfully completed its third flyby over Jupiter’s mysterious cloud tops. Jupiter’s ‘pearl.’ Image credit: NASA / JPL-Caltech / SwRI / MSSS. At the time of closest approach, Juno was about 2,580 miles (4,150 km) above the gas giant’s roiling cloud tops and traveling at a speed of about 129,000 mph (57.8 km per second) relative to the planet. Seven instruments and the spacecraft’s JunoCam were...