3.) Click on the Flood Fill Tool (Paint Bucket) and click in the selected circle with the following settings:
    Tolerance=10
    Fill Style=Sunburst Gradient
    Under Options Button: Verticle=75% Horizontal=25%
    Tolerance=10

4.) OPTIONAL! Click on the Airbrush Tool and using a complimentary darker color (Purple in this example) Airbrush the lower right 75% of the sphere. I use an Opacity setting of NOTE: This is Optional but if your pretty good at using the Airbrush Tool you might want to give it a try. If your not good with Airbrush Tool then Save your work at this point and try it. (You should always save your work after each completed step as a rule of thumb, I even save each step of a technique as a seperate file also so I can go back to a perticular step any time.)