1. Using the Elliptical Marquee Tool create a cirlce. With the circle still selected go to Filter> Render> Clouds.
2. Next go back to Filter> Render> and select Difference Clouds. You can do this several times to get the effect you want.
3. With the circle still selected go to Filter> Distort> Spherize.
4. To give the planet color go to Image> Adjustments> Color Balance and move the sliders around for Shadows, Midtones, and Highlights until you have the color and brightness you want.
5. Check out the Outer Space tutorial to learn how to make the background.
