looks ANGELES -- Our solar scheme i...

looks ANGELES -- Our solar scheme is suffering an identity crisis.

For decades, it has consisted of nine planets, level as scientists debated whether Pluto really belonged. Then the latter discovery of an object larger and farther away than Pluto threatened to project this slice of the cosmo into chaos.

Should this newly set up icy rock known as "2003 UB313" become the 10th planet? Should Pluto be demoted? And what exactly is a planet, anyway?

Ancient refinements regularly revised their answer to the last question and present-day scientists aren't earnestly better off: There still is no universal definition of "planet."

That all could promptly change, and with it science textbook around this planet.

At a 12-day discourse beginning today, scientists will carriage a galactic census of sorts. Among the possibilities at the meeting of the International Astronomical Union in the Czech Republic capital of Prague: Subtract Pluto or christen united more planet, and possibly dozens more.

"It's time we have a definition," said Alan hard who heads the space science division of the Southwest Research Institute. "It's embarrassing to the public that we as astronomers don't have one"

The debate intensified last summer when astronomer Michael Brown of the California Institute of Technology announced the discovery of a celestial aim larger than Pluto. Like Pluto, it is a member of the Kuiper Belt, a mysterious disc-shaped baldric beyond Neptune. Brown nicknamed his find "Xena" after a warrior heroine in a cheesy TV series; pending a formal name, it remains 2003 UB313

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