We didn't hold with the idea of "other planets".
Now we got 'em in all shapes and flavors - including backwards.
Thank your lucky stars you live in a relatively peaceful corner of the galaxy. Astronomers have found six large planets whose off-kilter orbits suggest that they crashed through their solar systems, swallowing any smaller planets that got in their way. The findings indicate that solar system formation is often disorderly and unpredictable, and that some potential cousins of Earth may have been destroyed in the chaos.I think Spock predicted this...
Astronomers have long thought that the formation of a star and its solar system was straightforward. A large cloud of gas and dust begins to congeal gravitationally, starts rotating, and eventually flattens into an object called a protostellar disk. That rotation dictates the future spin of the sun and the orbit of its planets. This is essentially what happened in our own solar system. There can be irregularities, of course, such as the odd spin axis of Uranus, which for as-yet-unexplained reasons is nearly tilted on its side, and Pluto's odd orbit, which occasionally takes it inside the path of Neptune. But these oddballs are nothing compared with what astronomers are seeing with six newly discovered planets known as hot Jupiters.
Hot Jupiters resemble our largest planet in size and composition, yet they orbit much closer to their stars, sometimes well within what would be the orbit of Mercury. But the newly discovered worlds add an extra twist: all orbit in the opposite direction from all of the other objects in their solar system (a so-called retrograde orbit), and all orbit at severe angles. [More]