[quote=The15thSpycrab]
So the whole representation of Earth is the four ships in the Dark Abyss squadron, the destroyer we commandeered, and various settlements and space stations throughout the solar system? (And maybe a few stations outside the solar system.) Also, I'd like to point out that the moon is pretty much doomed.
[/quote]

Keep in mind that Jason, and Sly's character are the only humans left alive. The Haven Alliance still has its home planets and its space stations, as well as captured planets. And the rest of their forces. The only survivors of the Earth battle are as you said. 

Also keep in mind the moon got destroyed when the Planet Destroyer smashed straight through it