It has been a while since I have posted. That does not mean that I have not been thinking. I have a very long list of ideas and a few partly written posts; I just have not had much time to write. Hopefully I will get a few more out on a regular basis, but I expect it to be more fits and starts as I work several at one time and occasionally finish multiples together. We will see....
On with this post...
What's in a name? that which we call a rose
By any other name would smell as sweet;
-Shakespeare, Romeo and Juliet
18 Feb 1930 – 18 Aug 2006
RIP, Pluto
On August 18, we marked the third anniversary of the passing of an old friend. On that date, five percent of scientists voted to pull the rug out under Pluto’s claim to planethood. This is not the first time this has happened. Ceres, discovered in 1801, was named a planet at one point. Later, the planets Pallas, Juno and Vesta (1802, 1804 and 1807, respectively) were added to the list. Over subsequent decades, several more bodies were found orbiting the sun between Mars and Jupiter, were named and given symbols in the manner of other planets. By the mid-1800’s, their number grew to the point that scientists had to acknowledge their definition of a planet was too liberal and had to be modified. At that point, the terms ‘asteroid’ and ‘minor planet’ came to be used for bodies in the asteroid belt, excluding the first four, which were still planets. Eventually (there is no definite time of death for them), the first four planetary homicides were committed by mankind. This took place through the delisting of them as planets in astronomical almanacs or alterations in nomenclature in such journals and in scientific observation.
Ceres, which went through several designations of planet, minor planet and asteroid (and was even given dual designation for a time), settled into what appeared to be permanent status as an asteroid until 2006. Ironically, it was in that year, simultaneous with the reduction in Pluto’s status, Ceres was once again elevated to minor planet. No one is quite sure if Ceres still carries the second designation as asteroid along with being a minor planet.
So why all the executions and exhumations? Scientists would have us believe it is all in the name of precision; we must be most careful and accurate in the way we classify. In fact, the careful precision is a necessary by product of practicality, born partly of shame from the lack of foresight that allowed us into this predicament.
If the total number of bodies sizeable enough to achieve a semi-spherical shape was in the single or low double digits, we could name them all planets and no one would say ‘boo’ (at least until we explored another solar system in which this was not the case). But, as going about things in this freewheeling manner results in a fairly large number of planets, with multiples sharing the same orbits, things get ugly in a hurry. So, we have to create constraints to bring the numbers back down. But is it necessary to rescind planetary status in order to do this?
It would be a simple enough thing to say, ‘this much and no more’, limiting planets to those bodies already bearing the definition. We could also say, ‘future discoveries must meet certain criteria to be designated planets’, allowing for minimal expansion, while grandfathering existing planets. All of these offend scientific sensibility because they rely on sentiment or tradition rather than a well-defined system of classification.
So there it is, in the name of consistency and scientific discipline, we must sacrifice our beloved nine (or ten or fourteen) planet solar-system and forever declare our planet to be one of eight, right? Well, no….
Many scientists claim that the agreed upon definition of planet excludes Earth, Jupiter and Neptune because they have not ‘cleared their neighborhood’ of other orbiting objects. This does not mean that they are not planets, as all eight planets are named in footnotes, but this could be done without even including a definition.
But all of this is beside the point. The criteria described for qualification as a planet is clearly worded to include the eight named planets and exclude Pluto, Eris, Ceres and the rest of the ‘dwarf planets’. This is quite an unscientific way to go about things; they just as easily could have created a definition to include some of the smaller planets (as some proposals did); it is also quite easy to imagine a scenario involving a body that all agree is a planet, but does not meet the criteria.
Of course, it is easy to criticize and much harder to offer solutions to the problem. This is where I go out on a limb as a non-scientist and offer my proposal:
First, I think the easiest way to go about this is to subdivide the category of planets (as is done with animals, flora, etc) into groups such as dwarf planets, minor planets, intermediate planets and major planets (and possibly superplanets, for use with some of the larger bodies discovered orbiting other stars). It might even be useful to have a multi-faceted definition including such descriptions as terrestrial, gas and ice, as well as double and triple. Using this, Pluto may be a triple or quadruple ice dwarf planet, while Earth would be a single intermediate terrestrial planet. Complicated? Yes, but it would be a consistent definition that would likely prove useful in extra-solar discoveries. It would also still be possible to define a group we call ‘historical planets’, which would include the nine I grew up with, along with Ceres and possibly Eris, which is the ninth largest known body orbiting the sun and largest in Pluto’s neighborhood (Kuiper belt); I would argue that this list is significant for more than sentimental reasons, as it outlines the expansion of our knowledge of the solar system.
JMHO, one of many I have (and believe make at least as much sense as those of the ‘experts’).
