The upper atmosphere of Jupiter is hotter than expected from the amount of sunlight that it receives: the average temperature should be about minus 73 degrees Celsius; instead, the measured value soars to around 426 degrees Celsius. The source of this extra heat has remained elusive for 50 years, causing planetary scientists to refer to the discrepancy as an ‘energy crisis.’ Now, using data from NASA’s Juno spacecraft, the W.M. Keck Observatory...
