I just read (thanks to the Boston.com News Alert) that Pluto is no longer a
planet. Wow, I imagine that there will be a lot of shoe boxes with
painted Styrofoam balls in this week’s recycling. I know that my sense of
universe has been altered. Alright, maybe not; after all, my only real
connection with Pluto was wondering why a dog had a dog as a pet. But, I
think (wait for it, here comes the ASP link….) that this is a teachable
moment for our students.
The declassification of Pluto as a planet is a result of a change in the
rules that define planets. This is an eerie parallel to our legal system;
after all, whenever an authority (be it scientific, legislative or judicial)
decides to change a rule, the consequences can be quite dramatic. Not
only that, but the thought process and debate that went into the change in the
definition of "planet" were strikingly similar to rules synthesis and
legal analysis. After all, the scientists concluded that a planet was:
”a celestial body that is in orbit around the sun, has sufficient
mass for its self-gravity to overcome rigid body forces so that it assumes a
… nearly round shape, and has cleared the neighborhood around its orbit.”
(from AP article located on NYTimes.com).
Think of this as an elemental test (not in the chemistry way). To be a
planet, you must: (1) be in orbit around the sun; (2) have sufficient
mass for self-gravity to overcome rigid body forces so that you assume a nearly
round shape and; (3) a clear neighborhood around your orbit. If you
cannot prove all of these things, you are not a planet. (I may actually
be a planet, but I digress.) Pluto couldn’t show sufficient evidence on
the third element.
The scientists who synthesized this rule clearly
were shooting for the stars here (pun awful, but intended). They were
seeking a universal (again, awful but intended) rule that would draw a line
that was less likely to be arbitrary than the rule they already had. This
is exactly what the legal system tries to do in fashioning rules. We are
always seeking to create a better, less arbitrary and longer-lasting
rule. We strive in our analysis of rules to synthesize the one statement
of the rule that is the fairest statement of what we want the law to be.
Also, the scientists addressed the "floodgates" issues. By
allowing Pluto planet status, they would have been forced to allow a number of
other undeserving large rocks to be called planets as well. Instead, the
scientists created a tiered system which classifies Pluto and some others as
dwarf planets (sleepy, dopey, etc… I couldn’t resist), but not as "classical
planets."
In the end, we lose a planet but gain insight into legal reasoning.
Hi-ho. (ezs)
