New York TimesIN the not-too-distant future, maps of the solar system may be redrawn to add another planet - or perhaps take one away. Last month, when scientists announced the discovery of a possible 10th planet, some nine billion miles from the Sun, they reignited a long-running debate about what a true planet is. They are grappling with whether the newly found celestial body, known for now as 2003 UB313, should be granted planetary status, and if it is not, whether Pluto, a like-size ice ball in a far orbit of the Sun, should be stripped of the title.