Pluto rules!

Sinai star gazing

Pluto, the new dwarf planet


There was always something odd about Pluto. It’s orbit was much more elliptical than those of the other planets and inclined at a maverick angle. It was also extremely small: smaller than our moon! There’s no chance you can see it with the naked eye. Even with a 12” telescope, it’s lost amongst the dimmest stars.

Then in 2006, at a meeting in Prague, the International Astronomical Union decided Pluto wasn’t a proper planet at all and reclassified it as a dwarf planet! The public were dismayed. Hordes of people who had never seen it and wouldn’t have any idea where to look for it wore T-shirts in protest, “Save Pluto”, “Pluto sues for Slander”, “It’s OK Pluto, I’m not a planet either”. Headlines across the world expressed outrage, “Pluto dumped by the über-nerds in Prague”.

But the maverick planet, errant dwarf or whatever you want to call it, is actually part of the biggest revolution in our understanding of the solar system since Copernicus first placed the sun in the centre. The über-nerds were right! Pluto is different. It belongs to a whole world beyond Neptune which is just now being revealed.

The primeval cloud from which our solar system was formed was much larger than we used to think and there’s lots of it still left. This has given rise to two newly recognized regions: the Kuiper Belt (say it to rhyme with Viper Belt, only the Dutch know how to pronounce it properly!) which lies beyond Neptune, and the Oort Cloud (say it like Ort, Dutch again!) which is much further out, half way between us and the next star.

The Kuiper Belt is occupied by a chaotic jumble of planetesimals, aggregates of dust and ice that haven’t formed into full sized planets and therefore don’t have the gravitational punch needed to clean out their paths. Not surprising, really, since they are much further out than our local planets and therefore more thinly distributed with a much smaller statistical chance of meeting up and coalescing into a few major planets. The big planets, on the other hand, have sucked in all the other debris and cleaned out their paths.

Rather than being an odd member of our planetary family, Pluto is now recognized as a typical member of the Kuiper Belt along with many others, for example: Eris, named after the Greek god of strife and discord; Makemake, named after the creator god of the Easter Islands; Haumea, named after the Hawaiian goddess of childbirth; Quaoar, named after the creator God of the original natives of Los Angeles; Orcus, named after the Etruscan god of the underworld; Varuna, named after the Hindu god who presides over the waters of heaven and the oceans; Sedna, named after the Inuit god of the deep seas. Getting the drift? Pluto, god of the Greek underworld, has become the Chief of a whole band of rehabilitated creator gods lurking in the still unformed outer regions of our solar system. Not bad for a dwarf! Who would want to be a boring planet?

This blog first appeared as an article for the Cairo BCA Magazine in August, 2010, to attract residents to the Sinai for star gazing with an 8″ Meade LX90 Telescope.

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