"It was one of the better storms of the year so far," says Ashcraft. "In the audio specimen you can hear the emissions on two of my shortwave radios. One radio is tuned to 21.1 MHz and the other at 18.9 MHz." (Plug stereo headphones into your computer; they will separate the two frequencies into left and right ears.)
Radio storms on Jupiter come from natural radio lasers in the giant planet's magnetosphere. Electrical currents flowing between Jupiter's upper atmosphere and the volcanic moon Io can boost these emissions to power levels easily detected by ham radio antennas on Earth.
Jupiter's outbursts could become more intense in the weeks ahead. Why? Because the distance between Jupiter and Earth is shrinking to a minimum on May 10th. "As Jupiter passes closer to Earth in our orbits, the periodic Io-induced radio storms should get stronger," notes Ashcraft.
To learn more about radio storms on Jupiter, and how you can observe them yourself, visit NASA's RadioJove web site.