The prevailing view on the origin of the Cold Classical Kuiper Belt is that Neptune was responsible for harassing, i.e., perturbing, these objects from within the Solar System to their current position at the outer edge of the solar system. New research by a University of Victoria graduate student, Alex Parker, and his supervisor, JJ Kavelaars, at the National Research Council's Herzberg Institute of Astrophysics, has shown that is unlikely to have happened.
It turns out that binary Kuiper Belt Objects (KBOs) are quite common in the Cold Classical Kuiper Belt. We're not quite sure how these binaries form but there is no doubt they are there. Well, the simulations run by Parker and Kavelaars showed conclusively that if Neptune was responsible for moving the objects to their current position, all of the binaries KBOs would have been destroyed in the process. This will cause astronomers to rethink their ideas on how the Kuiper Belt and the rest of our Solar system was formed.
And we are still no closer to understanding how the binary Kuiper Belt objects are formed