Earth is the product of three earths, merged into one planet. First is the version from Space Cases... That part makes up the huge metropolis, Rigelia City. Second is Earth that Was from Firefly... A giant desert, where nothing lives or grows. Also from that series is a huge chunk taken out of one side of the planet... Perhaps an explosion of some sort or a meteor strike. The indentation makes the planet crescent shaped... And the wound reaches far into the planet's mantle. It is called the Gaia Scar.
The third part is the version of Earth from the end of Alien: Resurrection. Around the Gaia Scar is a slew of dilapidated buildings, including what might have once been the Eiffle Tower. Everything is derelict, and nothing is livable by normal sentient beings... However, within the Gaia scar, an Alien colony has been thriving.
So, what's going on with Earth? When the Universes combined, the Blue Sun Corporation extended its roots into Earth, excited that it actually existed again. Through Rigelia are scattered influences of Blue Sun... A Starship Plant, a Lab, even an Academy called the Blue Sun Academy. All over the place, too, can be found Blue Sun vending machines that dispense free soft drinks. It seems the Corp. is quite generous!
In the center of Rigelia City is the STARDOG HQ. Since it is a military establishment, regular visits aren't allowed, though one can schedule a tour almost all the time. It's been said that the Aliance has attempted to buy out the STARDOG HQ, though so far, there has been little luck there.
Across the desert is the Earth Xeno colony. Thankfully, their queen is actually rather tame, or seems to be. Xenos that come from that colony are actually somewhat docile, and it's been discovered that they can actually speak telepathically, and even hold civil conversations. Though still considered dangerous, they are welcome in Rigelia City... Though they are, of course, highly scrutinized. Methods have been devised to immobilize them if they snap, and representatives to the queen have made this very clear. The terms are accepted. It seems like this particular colony wants only to be able to have a chance to belong in society.
The thing is, no one is exactly sure /why/ this is the case. Any attempt to investigate is met with resistance bordering on hostility, thus, the Powers-That-Be have decided that if the colony is going to be civil, they will leave well enough alone.
...Rumors, though, speculate the the Blue Sun Labs are at least partially responsible. Whether that's a good thing of a bad thing is yet to be determined.
And there you go. Maybe Earth ISN'T so boring, after all!