Mutiple Earths seem to be part of a strange anomaly in Z-14. Far across the universe,it was discovered that planets and solar systems repeat each other,but not perfectly. This causes mutiple versions of planets (Green Irks,two mooned Earths,etc) to be discovered. These mutiple planets seem to form in the farthest reaches of space. These mutiple planets may cause serious risks to the empire. Due to their unpredictable inhabitants,this may cause another version of the empire itself to form(Along with anything else.)
The most preffered explanation for a multiple planet to form is that, it is essentially the Universe repeating itself; Since the Universe is infinite or practically infinite, there's going to be more and more planets, as one would expect; However, these planets are still bound to the laws of physics, and as such, the amount of things that could reasonably exist is limited. Because of the vast combinations of how a planet can differ, however, multiple planets are extremely rare, and only a few documented cases are known of.