SALT LAKE CITY (KTVX) – The Juno spacecraft orbiting Jupiter has discovered an FM radio signal coming from the moon Ganymede. The find is a first-time detection from the moon.

“It’s not E.T.,” said Patrick Wiggins, one of NASA’s Ambassadors to Utah. “It’s more of a natural function.”

Juno was traveling across the polar region of Jupiter — where magnetic field lines connect to Ganymede — when it crossed the radio source. Scientifically, it is called a “decametric radio emission.”

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According to, Jupiter’s radio emissions were discovered in 1955, and over the last 66 years, more and more discoveries have been made about how the signals work.

“A member of the Salt Lake Astronomical society once built an amateur radio telescope that could detect the electromagnetic radiation from Jupiter,” Wiggins said.

Juno’s mission is to study how the planet Jupiter formed and how it evolved.

“Juno will observe Jupiter’s gravity and magnetic fields, atmospheric dynamics and composition, and evolution,” according to NASA.

What caused the radio emissions from Jupiter’s moon? Electrons, not aliens, caused the signals.

The electrons oscillate at a lower rate than they spin, causing the electrons to amplify radio waves very rapidly. The process is called cyclotron maser instability (CMI). The electrons that generate the radio signal can also cause auroras in the far-ultraviolet spectrum, a phenomenon also observed by the camera on Juno.

The spacecraft saw the moon’s radio emission for only five seconds. It was flying by at 50 km per second — a screaming 111,847 mph.