Whistler Waves Recorded by NASA’s Van Allen Probes

On May 4, 2017, NASA’s Van Allen Probes recorded these whistler waves in space above Earth. Waves like these are created by lightening discharges in Earth’s atmosphere. The signals bounce back and forth along Earth’s magnetic field lines, creating the unique whistling tone. This video shows the data from Electric and Magnetic Field Instrument Suite and Integrated Science, the instrument aboard the Van Allen Probes that recorded the sounds. A range of frequencies are shown low to high along the vertical axis and the strength of the signal at each frequency and time are color coded — blue being weak and red being strong. Credit: University of Iowa