Make It An Even Dozen

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The International Astronomical Union (IAU) has redefined what constitutes a planet.  Based on that definition, a panel of astronomers, writers and historians has suggested adding three more to the current number of planets in our solar system, bringin up the total from 9 to 12.  It is possible that more may be added to the lineup.  The panel's recommendations will be presented at a meeting of the IAU in Prague. The Union's general assembly is expected to formally vote on the recommendation next week.

If approved, the new additions would be: Ceres, the largest body in the asteroid belt that  inhabits the space between Mars and Jupiter; Charon, once considered Pluto's (which has long had its own problems with identity among the elite group of planets) moon will now become its companion in a "double planet" system;  and an as-yet-unnamed object, larger-than-Pluto and far beyond the orbit of all the other planets , with the unwieldy label of 2003 UB313 which was discovered by Cal Tech astronomer, Michael Brown and his colleagues in 2003 who tentatively named it Xena.

For the first time since 1930 when Clyde Tombaugh discovered Pluto, school children all over the world will have to learn new names of planets and more material will be needed for designing all those planetary system models for the science fair.  Under the newly defined system,   Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune — will be characterized as "classical planets." Ceres, Pluto, Charon and the unnamed planet will become "dwarfs," -  planets smaller than Mercury, which has a diameter of about 3,000 miles. 

This is so cool - revisiting and renaming heavenly bodies. It is like a breath of fresh air in the midst of the putrid smell of war, terrorism, unrest, unease and name calling by slimy politicians.  Broadening the horizons of human knowledge and expanding our consciousness of the universe by inquisitive visionaries, as opposed to the fast shrinking humanity and myopic visions of small minded political leaders.

There is just one small problem.  For years, American school kids have memorized the the following handy mnemonic "My Very Eager Mother Just Served Us Nine Pizzas" to remember the planetary order from the sun.  Now with the introduction of one "C" between Mars and Jupiter, another after (or before?) Pluto, and possibly an "X" at the end, can any one suggest a new aid to memory?  Readers?

Here is an article from the Scientfic American.

The original definition of planet is wanderer, from the Greeks who watched these bright lights wander through the firmament of fixed stars. Observers discerned nine of these travelers over the course of human history, the last being Pluto in 1930. But recent discoveries of more objects orbiting the sun, both bigger than Pluto and similarly rounded in shape, called into question the arbitrary limit of nine, with some proposing that Pluto did not merit its planetary status. Now the International Astronomical Union (IAU) has crafted a new definition for what constitutes a planet that would expand the solar system to Pluto and beyond, encompassing 12 bodies in all.

The new proposed definition of a planet is: a celestial body with sufficient mass to assume a nearly spherical shape that orbits a star without being another star or a satellite of another planet. By this definition, the list of planets in order from the sun now reads: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto-Charon (considered a double-planet system) and the newly discovered and officially unnamed 2003 UB₃₁₃, otherwise known as Xena. The committee also proposed a new category of planets, called plutons, be applied to those bodies that, like Pluto, both take longer than 200 Earth years to revolve around the sun and have eccentric orbits outside the typical orbital plane.

Comments

[Sujatha]

The mnemonic can be very easily modified to add the extra letters as in "My Very Eager Mother Cathy Just Served Us Nine Chocolate Pancakes on __day". They could use Xmas if Xena is the name confirmed for 2003UB313.

[Ruchira Paul]

Very good Sujatha! And you kept up the attractive theme of food. I was coming up with something unsavory like "Chicken PoX" for the end. Not the nicest thing for young kids to memorize.

[Sujatha]

Pluto's been demoted! So the new mnemonic could read "My Very Eager Mother Just Served Us Noodles". A bit of a letdown, in a way- I was looking forward to the new additions to planethood.

[Ruchira Paul]

I just saw the news. I too am disappointed. Not so much because there won't be any further additions but because poor Pluto got bumped! Having "lived" with Pluto all my life, there is a tender spot in my heart (as I am sure is in everyone else's) for this small and faraway "planet / planetoid." Pluto was always a wannabe planet and its status is somewhat like that of a "kicker" in American football. Not quite as glamorous or essential like all the other players on the field, but you need it to complete the picture or decide the game!