Making Planets with Gimp
There's a rather good filter that turns flat objects into a SPHERE
Its under MAP OBJECTS
but you have to give it something to work on!
I used a textured paint brushs and then added CHROME
oops once and rough but applying CHROME might I lost my transparent Background !
So a bit of editing with the eraser and
WE have the beginnings of something
A bit more shadow and tonal contrast added using smudge and eraser and other tools and brushes that darken and lighten
Part Two the whole planet and some color !