Dwarf Planet Discovery Hints at Hidden World Orbiting Solar System
Plenty of dwarf planets hide out beyond Pluto, perhaps steered by something much bigger.
Discovery of an icy "dwarf" world beyond Pluto hints that a much bigger planet may hide even farther out in the dim reaches of the solar system, astronomers suggested on Wednesday. (Read "Our Solar System" in National Geographic magazine.)
They point to the discovery of the dwarf planet with an orbit they see as stretched out by the mystery planet as evidence that it lurks about 250 times farther away from the sun than Earth. (See "Dwarf Planets.")
The same mystery planet, perhaps two to ten times heavier than the Earth, may have stretched out the orbit of another dwarf-planet-size object called Sedna, discovered ten years ago, also orbiting far beyond Pluto.
"A rogue planet could have been ejected from our
