In this tutorial we are going to see how to create a planet from scratch. It’s really very easy and involves very few steps only. This is how the final output looks.
Open a document of any size you desire with a black background.
Create a new layer. Press D to set foreground and background color to set as black and white respectively. Press X to swap foreground and background colors. Now go to Filter-> Render-> Clouds.
Now go to Filter->Stylize->Emboss and give any value that will satisfy you and this is the output you will get.
Now make a circular selection in the center and press Ctrl+Shift+I to make inverse selection and delete that part. Now again press Ctrl+Shift+I to reselect the same circular region and now apply Filter-> Distort -> Spherize. You will be getting something similar to this.
Now go to layer styles and apply the following layer styles.
This is the output you will be getting.
Now create a new layer create another circle of lesser size than the planet and fill it with black. Move it to a corner of the planet.
Now apply Filter-> Blur-> Gaussian Blur to a value of 30-45 and adjust it back to the corner so that you get something like this.
Now go back to the layer in which the planet is available. Choose the dodge tool and dodge the corners of the planet where it is lighted to create more highlights. This is how it should look after dodging the corners.
Therefore, your planet is ready.
Corollary: If you want you can give a mild outer glow around the planet to give more pleasing effect.
To create nebula background or a space scene I have already given a tutorial and it is available here.