Bad News for Pluto as "10th Planet" Is Sized Up

A German team of astronomers from the University of Bonn claims that the newly discovered object at the outskirts of the solar system is, in fact, larger than Pluto. Pluto fans are, naturally, offended.

For more than seven decades, schoolchildren have been taught that tiny, lonely Pluto is the outermost of the nine planets that orbit the Sun.

Now, thanks to German astronomers, a big hole has now been bashed into that cherished piece of learning. A team led by Frank Bertoldi of the University of Bonn in Germany has determined that Pluto is much smaller than an enigmatic object, 2003 UB313, whose discoverers claim is the solar system's 10th planet. 

UB313, found some 15 billion kilometers (nine billion miles) from Earth, ignited a huge row after its finding was announced last July 30 by an American team. Pluto's defenders blasted UB313, saying it was not a planet... but a vulgar rock. 

The polite term for such abuse is Kuiper Belt Object (KBO), which is used to describe the estimated 100,000 pieces of icy, primeval debris that slowly encircle the Sun on the outskirts of the solar system, far beyond the orbit of Neptune.