Listen to the radio wave passing through Venus' atmosphere
Radio occultation is a technique for probing the structure of a planetary atmosphere using radio waves transmitted from a spacecraft when the spacecraft goes behind the planet as seen from the Earth. The radio wave grazes the planetary atmosphere and is received by an antenna at the ground station. The frequency and the intensity of the received radio wave change with time. The sound given here was created from Akatsuki's radio occultation data by shifting the frequency of the radio wave to the range which humans can hear. In this experiment, conducted on May 6, 2016, the pitch rises in the first half due to the motion of the spacecraft and the Earth (Doppler effect), and then the pitch drops and the sound level fluctuates as refraction in the Venus' atmosphere begins to have an effect. The refraction angle is calculated from the frequency shift, and then the refractivity of the atmosphere is obtained. The altitude distributions of the pressure and the temperature are further deduced.
by Ralph D. Lorenz (Johns Hopkins Applied Physics Laboratory, USA) and RS Team