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.

Researchers led by Brett Gladman of the University of British Columbia first spotted the maverick object in May. Observations suggest it is about 50 kilometres across and travels on a path that takes it from the distance of Uranus to more than twice that of Neptune (or between 20 and 70 astronomical units from the Sun, with 1 AU being the Earth-Sun distance).