Pluto, We Hardly Knew Ye »
The International Astronomical Union, meeting in Prague, agreed on a proposal to define what exactly makes up a planet - and in so doing, trimmed our solar system to eight "classical" planets, unceremoniously giving Pluto the boot.
The new rules say that not only must a planet orbit the sun and be large enough to assume a generally round shape, but that it must "clear the neighborhood around its orbit" - something not done by Pluto because its orbit periodically overlaps that of Neptune (no word on why Neptune makes the cut with this happening - apparently this road doesn't travel in both directions).
