Figure 6-24: Optical and Radio Views of Saturn (a) This picture was taken by a spacecraft 18 million kilometers from Saturn. The view was produced by sunlight reflecting from the planet’s cloudtops and rings. (b) The image is made by using radio waves, which is indicated by the highlighted R in the wavelength tab. This VLA image shows radio emission from Saturn at a wavelength of 2 cm. In this false-color image, the most intense radio emission is shown in red, the least intense in blue. Yellow and green represent intermediate levels of radio intensity; black indicates no detectable radio emission. Note the radio “shadow” caused by Saturn’s rings where they lie in front of the planet.

(NASA)