The Pokemon Universe is some sort of strange universe with freaky creatures based off of real things in it. Other than the unnamed planet, the only other stuff we saw in that universe is the moon, the sun, and some meteorite that had Deoxys in it. For instance, on the planet all we seen were the regions of Kanto, Johto, Hoenn, and Sinnoh. Oh, and those places in the spin-offs.
The planet also has some REALLY weird guys, like some idiot who usually wins Pokemon battles and some guy pretending to be a professor of Pokemon. Also, due to the lack of astrology in the games and the anime, we still barely know about their universe. All we know that Arceus (Note: They usually say that it seemingly, only created Sinnoh, so WTF?) made it, yet it got bored and it created Palkia and Dialga to be slaves and do the rest of the work, yet they're planning to get revenge (Despite the fact that they fought in one Pokemon Movie, yet it turned out that Darkrai stole their money. They blamed and fought each other, until they found out that Darkrai did it and decide to beat it up).