Add a 10th planet to the solar system - or possibly subtract one. Astronomers announced that they had found a lump of rock and ice that is larger than Pluto and the farthest known object in the solar system. The discovery will probably rekindle debate over the definition of what is a planet and whether Pluto still merits the designation. The new object - as yet unnamed, but temporarily known as 2003 UB313 - is now 9 billion miles, or almost 14.5 billion kilometers, away from the Sun, or 97 times as far away as the Earth and about three times Pluto's current distance from the Sun.