Pluto on the chopping block

For decades, the solar system has consisted of nine planets, even as scientists debated whether Pluto really belonged. Then the recent discovery of an object larger and farther away than Pluto threatened to throw this slice of the cosmos into chaos.

Among the possibilities at the 12-day meeting of the International Astronomical Union in the Czech Republic capital: Subtract Pluto or christen one more planet, and possibly dozens more.

But the decision won’t be an easy one. Scientists attending the conference are split over whether Pluto should be excluded from the list of planets, Pavel Suchan of the meeting’s local organization committee said.