A NASA Juno space craft has detected a mysterious five-second radio signal from one of Jupiter's moons. The strange signal is understood to have come from Ganymede and was detected. NASA said the signal lasted just five seconds and the discovery marks the first time a detection has come from the moon. At the time of detection, Juno was travelling across the polar region of Jupiter, where magnetic field lines connect to Ganymede at a speed of 111,847mph. NASA ambassador Patrick Wiggins, from Utah, told news outlet KTVX: "It's not extraterrestrial. It's more of a natural function. According to the publication, the signal was most likely caused by electrons oscillating at a lower rate than at which they spin, amplifying radio waves. The same process was also reportedly behind similar signals coming from Jupiter as detected by Juno in 2017. NASA most distant planetary orbiter will now continue its investigation of the solar system’s largest planet through September 2025, or until the spacecraft’s end of life. This expansion tasks Juno with becoming an explorer of the full Jovian system Jupiter and its rings and moons with multiple rendezvous planned for three of Jupiter’s most intriguing Galilean moons: Ganymede, Europa, and Io.