Free "Is Pluto a Planet?" fact sheet for teachers online

In article ,
Magnificent Universe wrote:
A free fact sheet summarizing arguments both for and against Pluto's
planethood is now available for teachers and others interested in the Pluto
controversy. This is a PDF file that can be downloaded from
http://www.boydsmillspress.com/pluto.pdf . Please allow a couple minutes to
download.

That fact sheet "forgets" to mention the fact that Ceres, Pallas, Juno and Vesta
were considered to be "planets" during the first half of the 1800's. Then a
large number of additional asteroids were discovered, and Ceres, Pallas, Juno
and Vesta lost their planetary status.

Now, this process is repeated for the "second asteroid belt", i.e. the Kuiper
belt. Some 150 years ago, there were probably people who didn't like that
Ceres, Pallas, Juno, Vesta lost their planetary status, for the same emotional
resonas that some people today want to continue considering Pluto a planet.
But 150 years into the future, people will be used to Pluto not being a planet,
just like we today are used to Ceres, Pallas, Juno, Vesta not being planets.

--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/

Paul Schlyter writes:

That fact sheet "forgets" to mention the fact that Ceres, Pallas, Juno and Vesta
were considered to be "planets" during the first half of the 1800's.

And all of the 1900s. And the first few years of the 2000s.

Then a large number of additional asteroids were discovered, and Ceres, Pallas,
Juno and Vesta lost their planetary status.

Incorrect; they were called "minor" planets. That does not constitute loss
of planetary status. It constitutes loss of "major" planetary status. There's
a big difference.

But 150 years into the future, people will be used to Pluto not being a planet,
just like we today are used to Ceres, Pallas, Juno, Vesta not being planets.

On the contrary, those asteroids have not been planets for only a few months.
How can you say we're used to it already? Heck, the Minor Planet Center hasn't
even changed its name to the Small Solar System Bodies Center yet.