Writing this article tooks me longer than the few lines of Povray code ...
  1. At first, you need a rectangular texture for the planet. For example, a map of the world:

    I used a map from Wikipedia which is in the Public Domain. I had to polish it a little bit with Gimp :-)

  2. Next, you need some Povray code:

    camera { location <0,0,-300> look_at <0,0,0> }

    light_source {
    <0,100,-400>
    color rgb <1,1,1>
    }

    sphere {
    <0,0,0> 100
    pigment{
    image_map {
    gif "Weltkarte.gif"
    map_type 1
    }
    }
    rotate<0,clock*360,0>
    }


    Where "Weltkarte.gif" is the name of the rectangular texture from above. Put that code in a file called earth.pov. Certainly, you can choose another file name, but then don't forget to change the file name also in the ini file:


  3. Now, create a file earth.ini which will be used to render a lot of images from the file above:

    Antialias=on
    Antialias_Threshold=0.1
    Antialias_Depth=2

    Input_File_Name=earth.pov

    Initial_Frame=1
    Final_Frame=60
    Initial_Clock=0
    Final_Clock=1
    Cyclic_Animation=on
    Pause_when_Done=off

  4. Render the ini file:

    povray earth.ini
    This results in 60 PNG files, numbered from earth01.png to earth60.png. If you want more intermediate steps, increase the parameter "Initial_Frame" in the ini file. Here is one of the files:



  5. Last not least, use the famous convert command from ImageMagick to combine the png files into one GIF animation:
    convert *png earth.gif

    And here you are:



    Now its on you: add the moon, the sun or other planets to complete the solar system. Or, if you have a really performant computer, create a whole galaxy ...