With this tutorial I am going to show you a way to create a nice glowing planet (sphere) effect. Here is an example
1. Start by creating a new document 40*40 pixels. Get the Paint bucket tool and fill it with a light blue color. Then with the Elliptical Marquee tool and select a perfet circle (hold down Shift while selecting) at the center of your document and fill it with white. You should now have an image like this.
2. Go to Edit -> Define Pattern and give your pattern a name. (If you want you can use the image above)
3. Close this document and create a new one with a size of 800*800 pixels.
4. Select the Paint Bucket Tool (Fill: Pattern) and fill your new document with the pattern we ‘ve just created.
5. Get the Elliptical Marquee tool and select a circle at the center of your document.
6. Go to Filter -> Distort-> Sperize and use Amount: 100% Mode: Normal.
7. Now we are going to inverse the selection. Go to Select -> Inverse (Ctrl+Shift+I). Fill the new selection with black and deselect (Ctrl+D)