Reply to: Wolfgang Benz

>
> Hi Bill
>
> Honestly, Pluto is still a planet, a dwarf planet. But in fact it was
> never treated like a major planet and up to now the best image
> we have is a blurry one of a few pixel in diameter. So I really
> cann't understand how so many people could build up a "love"
> relationship to it and why they get so emotinal although nearly
> all of them have never seen the thing they fight for by themselves
> (for sure more than 99% of them have never tried to find and
> see Pluto in the night sky (looking at HST and other big scope
> images doesn't count here)).
>
> Some time ago there was a post on the LX90 group:
> "New Mexico has just passed legislation to now designate
> officially PLUTO as a planet once again."
> The post got comments like:
> "Thanks to ... New Mexico for putting some sense back into
> astronomy and some integrity back into discoveries made
> of USA soil."
> and
> "Hurray for "Pluto Planet Day"!!!"
> and
> "At least someone has their head bolted down straight, Pluto
> will always be a planet to me and I don't care what anyone
> else says."
> This would be really funny if it wouldn't be so sad for science.
> How far will we come when politicians make scientific decis-
> ions like this in future ? Then we can save all the money that is
> spent for the unnecessary sciences and leave it all to money
> and power driven politicians ?
>
> There were also many headlines like:
> "IAU kicks Pluto out of the solar system"
> This would have been really good news, as if the IAU is able
> to do this with a dwarf planet, we don't have to be frightened
> by NEOs anymore as they are much less massive and the
> IAU can do it with them much easier too ;-).
> Maybe the IAU can do it with our moon too ? Then we could
> double our usable clear nights.
>
> But its worst for the poor astrologers. They now have to fight
> for their existence and for their scientific background (against
> the dumb, intolerant astronomers) just to explain why a "non-
> planet" has so much influence on all the people on earth ;-)
>
> Obviously its for too many people not a matter of science but a
> matter of heart why Pluto MUST be a planet. Especially for the
> US folks. It looks like as its really important for their self-percep-
> tion to keep the one and only "planet" that was discovered in the
> US by an US american.
> Some others (especially the planetary science folks) support the
> "Pluto is a planet and the definition of a major planets must be
> in a way that there will be some more soon" just out of own
> interest to get more and easier funding and good PR when new
> "planets" are discovered.
>
> When the first astroids in the main belt were discovered (Ceres
> 1801, Pallas 1802, Juno 1804, Vesta 1807, ...), they were also
> classified as planets. But as soon as more and more of them
> were discovered, they lost the state again and were then called
> minor planets. Now its the very same with Pluto and the Plutinos.
> The orbits of Pluto and the Plutinos are dominated by Neptune in
> 2:3 resonance (alone this fact should be enough to disqualify
> Pluto as major planet). The only difference is that it took now
> some years more to discover more of them.
>
> The other main reason for Pluto as major planet is simply:
> I've learned it this way in school.
> Why did't these people complain about the fact that Ceres (and
> maybe a few others; with the original IAU draft even some more)
> would have become "real" planets although they didn't learn
> them in school ?
>
> Are these two totally unscientific reasons so important and the
> best justification on earth that the whole world must do it wrong
> for the rest of the existence of the human race ?
>
> Do we really want and need to get a new small "major" planet
> every few years?
> Then the astonomy books have to be changed and reprinted
> on and on. And the kids have really better things to do than
> having to learn the names of an increasing number of these
> small outer solar system rocks.
> Where is the limit before it gets insane ? 15 ? 25 ? 50 ? 100 ?
>
> The original IAU draft definition for the resolution at the GA was
> pretty unlucky. So it was no surprise for me that it didn't come
> through (I saw it all on the live video stream). The best suggestion
> (and the least scientifically attackable) was probably to delete
> the entire draft and just leave the footnote that named the 8 major
> planets from Mercury to Neptune explicitly. The passed resolution
> is IMO still not fully fermented (e.g. Jupiter too didn't "cleared the
> neighbourhood around its orbit", but the orbits of the Trojans are
> for sure "ruled" by Jupiter). But the passed resolution is at least
> flexible enough that a new planet can be added when a real big
> one is discovered out there.
>
>
> I don't care much if anything is changed in the Pluto software
> on this issue. But skipping Pluto from the planet selection will
> for sure cause more complaints than leaving it as it is.
> If something has to be changed then it will probably be driven
> by how the elements of Pluto and the dwarf planets are handeled
> by the MPC in future and if they are still available in the same
> form as they were in the past.
>
> Clear skies
> Wolfgang
>
>

Since Wolfgang is asking for responses here (even though it is not Guide
related) let me just say that the IAU definition (as he seems to
concede) is far from satisfactory. Their definition excludes
extra-solar planets (because they don't orbit the Sun) and Earth,
Jupiter and Neptune (because they haven't cleared their neighbourhoods)
- their definition seems to have been drafted on the last day as
something produced for the media without much thought.

Personally, I would be quite happy to say that a spheroidal body (other
than a star) orbiting a star should be called a planet. This wold
obviously exclude all comets and the overwhelming majority of asteroids.

If we're talking about matters of science rather than matters of heart,
then the current weaknesses in the official definition must be addressed
very quickly indeed before the IAU becomes a laughing stock for
introducing clearly inadequate definitions and then expecting everybody
to adhere to them.

With my proposed definition there would not be hundreds of new planets,
as the vast majority of newly discovered asteroids would not be
spheroidal, so the question of more and easier funding and good PR would
no more accompany the discovery of new asteroids than it does the
discovery of new comets.

If all the orbits of Pluto and the Plutinos are dominated by Neptune in
2:3 resonance (as Pluto obviously is) then this could perhaps form a
starting point for a new definition that would be better than the one
that we have now although care would need to be taken to exclude Pluto
and the Plutinos (and the Trojans) while including Neptune and Jupiter
respectively.

Astronomy books nowadays are rendered obsolete by new discoveries almost
as soon as they have been published, so having to change and reprint
astronomy books shouldn't be a problem.

--
Richard Mallett
Eaton Bray, Dunstable
South Beds. UK