The planet Jupiter is situated millions of miles away from Earth, home planet to Harry Potter. On Jupiter, there are forces unknown to Muggles. The few humans that know of this super-human life force are wizards known as Unspeakables, and the Minister of Magic himself. The Minister of Magic is absolutely forbidden to announce this fact to the public as there is no difference between the populations.
The populations of Jupiter consist of clones, which were all created in the image of each and every human on Earth. The Jupitarians' personalities are the exact same as the Earthians.
The reason for the clonage of the entire population of Earth is that millions of years before, there had been a great explosion on a planet, dividing it into nine pieces, all of which started rotating around the star that had caused this disruption. The explosion, fortunately, was not deadly to the human race. Every human that had been on the original planet was cloned so that the populations on each of the nine planets' peoples were exactly the same.
The reason for wizards on each planet is that the explosion affected certain people differently than others, giving them special powers.
However, not all the people who were affected were changed in the same way, hence giving some more powerful abilities than others, who might not receive any power at all through the generations: Squibs. And also there were people who weren't affected enough so as to receive the powers immediately, but through generations: Muggle-borns.