The Juno spacecraft orbiting Jupiter has discovered an FM radio signal coming from the moon Ganymede, a finding that marks a first-time detection from the moon, according to KTLA sister station KTVX in Salt Lake City, Utah.

“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.”