Getting rid of transparent planets

So I know a bunch of people, including myself, posted that their planets were "see-through," that is that their planets did not look like solid objects but rather transparent balls of light.

The original thread is here: https://forums.sinsofasolarempire.com/315009

Long story short, the problem was attributed to sub-spec graphics cards.  However, one person came up with a possible work-around that I could not figure out.

My solution: make a simple mod that changes the color and texture of the planet's surface, making it appear more solid.

The problem is that this is my first mod, and I really have no experience with computer graphics, so any help at all would be greatly appreciated.