Tag Archives: Pluto

Welcome, Styx and Kerberos

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Earlier today, the International Astronomical Union (IAU) voted on names for the two most recently discovered moons of Pluto.  The larger of the two, formerly designated P4 will now be known as Kerberos, while P5 has been named Styx.  The decision was a slight departure from the results predicted by a public poll, because those chosen names were already being used to describe other bodies.  While the results of that poll (Vulcan and Cerberus) were widely reported as definitive, it … Continue reading →

Why is Pluto not a planet?

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In 1930, Clyde W Tombaugh completed the search for Planet X, the outermost planet at the far reaches of the solar system.  This object was named Pluto.  Then, on 24 August 2006, the IAU (International Astronomy Union) formally voted on a new definition of the word ‘Planet’, which excluded Pluto.  For seventy-six years, our solar system had been understood to have nine planets, then suddenly it went back to eight.  The response was furious. Both the astronomical community and the … Continue reading →