In cosmic terms, Pluto had a short life as a planet. Discovered on this day in 1930, it was named for the Roman god of the underworld because it was the farthest planet from the sun. This made it great material for astrologers: from the depths of the underworld to the most distant planet in the heavens – Pluto could be transformative.
Then the bad news came: on August 24, 2006, astronomers demoted Pluto to a “dwarf planet.” Pluto the Planet, dead at 79.
This day is still special, though. Thirty years ago, my son was born.
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Pluto the Planet is not dead–far from it. The demotion was done by only four percent of the International Astronomical Union, most of whom are not planetary scientists. It was immediately rejected by hundreds of professional astronomers in a petition led by Dr. Alan Stern, Principal Investigator of NASA’s New Horizons mission to Pluto. You can find a copy of that petition here: http://www.ipetitions.com/petition/planetprotest/
Many astronomers continue to reject the demotion and are even now working behind the scenes to overturn it, or are choosing to simply ignore it. A far better planet definition is that any non-self-luminous spheroidal body that orbits a star is a planet. The roundness element is key, as it means the object is in a state of hydrostatic equilibrium, with its shape determined by gravity rather than by chemical bonds. By that definition, Pluto is very much a planet. You can read more about the science behind the rejection of Pluto’s demotion and worldwide efforts to get Pluto’s planet status reinstated on my Pluto blog at http://laurele.livejournal.com
Thank you, Laurel! I’m glad Pluto has someone watching out for it.