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Mercury Winter 2007 Table of Contents

For more than seven decades, remote Pluto was counted among the planetary canon. In August 2006, however, this world was effectively reclassified with the adoption of a new definition of "planet." Opinion among astronomers for and against this new definition is now regularly slung about, and there is anticipation of a coming showdown -- between, on the one side, those who favor retaining Pluto's planetary status and revisiting the new definition of "planet," and, on the other side, those who advocate for the new definition in the midst of a burgeoning number of recently discovered planetary bodies in the Solar System.

Here, two noted astronomers share their opinions on the issue.
Who Defines a Planet? by David A. Weintraub and The "Pluto" Question by Brian Marsden.

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