In a batch of 27 planets found outside our solar system, half a dozen have "wrong way" orbits, astronomers have announced.
Each of the six extrasolar planets, or exoplanets, orbits in the opposite direction as its star's rotation. Such backward motion is unlike anything seen in our solar system.
the discovery of these odd exoplanets challenges a leading theory for the formation of planets known as hot Jupiters, which in turn means that fewer Earthlike planets may exist in the universe.
Full story from National Geographic