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The fallen planet

Last year, the solar system was officially reduced to eight planets when Pluto was demoted by the International Astronomical Union. Here a member of the IAU explains why and how the decision was made

By Stephen Eales   May 2007

My Very Easy Method Just Speeds Up Naming Planets. Since 24th August 2006, children have had to find a new mnemonic for the names of the planets in the solar system, because on that day the International Astronomical Union voted to remove Pluto from the list of planets. The peculiar story of the fall of Pluto shows how human nature and politics can interfere even in astronomy, the most ethereal and beautiful of sciences.

The story starts over 200 years ago, in the back garden of a house in Bath, when William Herschel discovered a new planet—the first in modern…

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