From what I understood, that wasn't Earth. It was more of a mashup of the different planets, with parts from Earth, the asteroid the troll's party arrived in on, and I believe the deserted planet Mayor first appeared on.

The asteroid the troll came on landed went through a Skaian Defense Portal and landed on Earth. And surprise, surprise, that deserted planet we first met our dear Mr. Mayor, was in fact future pre-scatch Earth