SALT LAKE CITY (ABC4) – 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.

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

Juno was traveling across the polar region of Jupiter, where magnetic field lines connect to Ganymede, and that’s 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.

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

Juno’s mission is to study how the planet Jupiter formed and how it evolved. According to NASA, “Juno will observe Jupiter’s gravity and magnetic fields, atmospheric dynamics and composition, and evolution.”

What caused the radio emissions from Jupiter’s moon? Again, aliens are not sending the signal. Electrons cause the signals. The electrons oscillate at a lower rate than they spin.

This causes the electrons to amplify radio waves very rapidly. The process has an interesting name, cyclotron maser instability (CMI). The electrons that generate the radio signal can also cause auroras in the far-ultraviolet spectrum – which was 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. That is a screaming 111,847 mph. Because Juno was flying so fast, the source of the radio transmission was at least 250 kilometers (155.3 miles) in order for the sensors to pick it up.

So even though this time it wasn’t an alien transmission, Wiggins says “I do believe life is out there, but I’m still waiting for evidence to prove it.”

The radio signal is being called a shorter relative to the same thing that causes the auroras here on earth.

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