Seriously, I don't know.. why do things have to orbit a certain direction?
An object in the icy Kuiper belt has been found orbiting the Sun backwards, compared to most other objects in the solar system. It may help explain the origin of an enigmatic family of comets typified by Comet Halley.
The new object, called 2008 KV42, lies in the Kuiper belt, a ring of icy bodies beyond Neptune. Its orbit is inclined 103.5° to the plane of the Earth's orbit, or ecliptic. That means that as it orbits the Sun, it actually travels in the opposite direction to the planets.