Radio emissions from Jupiter… and other large planets

Tune to the right radio frequency, and you can listen to Jupiter! Electrons passing through Jupiter’s magnetic field are accelerated and give off radio waves, a process called cyclotron radiation. The intensity varies with Jupiter’s longitude, and careful tracking of the radio waves has enabled a more precise estimate of Jupiter’s rotation period (previously estimated based on cloud features, which naturally are not stationary). NASA’s Radio Jove project encourages teachers, students, amateurs (and you) to listen in to Jupiter’s “broadcasts.” Here are examples of the two main radio burst types you might hear:

The frequency of the radio waves is proportional to the strength of the magnetic field. Jupiter’s frequency varies between 10 and 40 MHz, yielding “decametric” waves (where the wavelength is measured in tens of meters). Other planets would have different frequencies. In fact, there’s an ongoing effort to determine if we can detect known exoplanets via radio observations (with LOFAR or SKA)—and if so, then add this to the growing list of exoplanet detection techniques. As of today, we’re up to 353 exoplanets discovered… with more coming every day.