Hi Heather,

There were some mention of people seeing a spot on the Sun many years before Galileo. But it really wasn't until he created the telescope and used it to study the Sun that scientists understood that these really were spots on the Sun and that they rotate with the Sun's rotation.

From this website: http://www.teachersdomain...lileosun/index.html, I found a nice discussion of this:

"In 1611, several people used the newly invented telescope to observe dark areas on the face of the Sun. At the time, no one had any idea what the dark spots might be. A German mathematician, Christoph Scheiner, hypothesized that the spots were satellites orbiting the Sun, a theory that preserved the accepted belief that the Sun, along with all heavenly bodies, was perfect and without blemishes. In contrast, Galileo's scientific observations of the dark spots led him to believe that they were actually located on the surface of the Sun."

Laura