Theme? As mentioned by some members above, the theme is meteor hence it should show some meteor showers, or at least a flying comet... Of course, it doesn't really have to be a typical meteor, you could use something else to portray a meteor.

For example, it depends on your idea of the illustration, and the "definition" of meteor that you want to portray in the illustration. Meteors are space rocks falling towards earth and gets burnt up in the atmosphere, so maybe your meteor can represent a destroyed spacestation crashing towards earth (or some sort of planet), with parts bursting into flames...

or just a simple meteor shower will do...

but nice photoshop