Page:The Music of the Spheres.djvu/232

 maximum again; thus the period from maximum to maximum is about 11 years.

Through watching these black spots disappear around one edge of the sun and then reappear after an interval of time on the other side, Galileo discovered that the sun turned completely around on its axis in 25 days. Further study disclosed the still stranger fact that the sun does not turn around in a solid body.