Fight for Pluto !, A Campaign to Reverse the Unjust Demotion Options

[Bob Shaw]

The stuckness that has to break is the notion that such categories have a service to play even when the universe provides no such categories. Larger KBOs may break the logjam there in the short run, but extrasolar discoveries will end up doing so in the long run.

I think you're quite correct - the trouble is that all the physical sciences have at some level a degree of 'butterfly-collecting' about them, and sciences where observations of classes of objects are paramount are more prone than any to the counting of angels upon the heads of pins. Our Solar System, and the universe in general, simply isn't a place which follows 'our' rules, and we should hardly be surprised when we find that imposed rules are futile.

The good thing about all this fuss regarding Pluto is that it's been 'interesting' enough to gain the attention of the general public; the bad news is that it's probably reinforced their preconceptions regarding astronomers (and all other scientists).

Poor old Alan Stern; he starts off with mission to the last planet, and just as it all comes together it's turned into just another asteroid survey (yawn). Well, it's still a planet to *me*, Alan, so there!


Bob Shaw

[laurele]

Pluto is still a planet to a lot of people. I'm waiting to hear more about Dr. Stern's conference of 1,000 astronomers later this year, which he is convening to address the issue. That conference is likely to bring this full circle. New Horizons may very well end up once again being a mission to a planet though not necessarily to "the last planet" in our solar system.

[Greg Hullender]

It seems odd to me to claim that the universe has no pattern in it. For example, it's not true that we'll find small planets with hydrogen atmospheres, nor massive ones that failed to clear their orbits, and I think it quite unlikely that we'll find massive but airless worlds. Where we do find patterns we don't expect (e.g. an all-water planet), then we'll learn something. But it's hard to see things that violate the expected pattern if there is no expected pattern at all.

[nprev]

Oh, there's a pattern for sure: things in nature exist along a continuum rather than in discrete categories (except for subatomic particles, which do seem to be distinctive entities with fixed properties). Therefore, the term "planet" cannot be anything other than a subjective reference concept, and it's probably better to use it in historical/cultural contexts rather than as a scientific descriptor.

[EDIT] Extending this line of thought, my argument is that Pluto is indeed a planet...but it's the LAST planet unless Nemesis or some other major body exists (unlikely)...anything else out there is a KBO, including Eris. The historical age of solar planet discovery is over.

[alan]

A quote from an article by David Jewitt & Jane X. Luu in Dædalus

We have to conclude that Tombaugh discovered Pluto not because of the quality of Lowell’s predictions, but simply because he was looking when nobody else was. These facts, however, did not distract astronomers at Lowell Observatory from advancing Pluto as a planet; and, in the absence of much public discussion until the discovery of the Kuiper Belt, these facts made little impression on the public. For all the wrong reasons, the ‘planet’ label stuck.

It is interesting to speculate on what might have happened had Pluto been properly described as a large kbo upon its discovery in 1930. Most likely, our understanding of the solar system would have been advanced by many decades. The next-brightest kbos after Pluto are fainter by a factor of fifteen or twenty. They would have been difficult for Tombaugh to locate, but astronomical sensitivity increases almost yearly and additional objects could have been identified within a decade or two. Indeed, some of the bright kbos found in recent years were also recorded in photographic observations from the 1950s and 1960s, but they went undetected. One of the main reasons for this is psychological: humans are not very good at perceiving things they do not expect to see. With Pluto entrenched in our minds as the ‘last planet,’ nobody was able to see even the bright kbos until this population had been firmly established in the 1990s.

If Pluto had been immediately recognized as the ‘tip of the Kuiper Belt iceberg,’ we would have known soon after World War II–and certainly before the space age–where comets come from and where to go in the solar system to find our most primitive materials. Our understanding of the dynamics and origin of the solar system would also have been much less biased by observations of the rocky planets and the inner solar system than it has been. The damage done by the mislabeling of Pluto as a planet, in this sense, has been considerable.

http://www.ifa.hawaii.edu/faculty/jewitt/p...s/2007/JL07.pdf

[Alan Stern]

What utter nonsense from Jewitt & Luu. They know that Lenard suggested in 1930, no less, that
Pluto was one of a larger population out there. They also know that people did do searches for both
planets and planetoids, all through from the 30s to the 70s (ending with Kowal's survey that found
the first Centaur, 2060 Chiron).

J&L also don't seem to recognize that Pluto's discovery foretold not just the KB but also an important
new class of planets- dwarf planets.

[David]

What utter nonsense from Jewitt & Luu. They know that Lenard suggested in 1930, no less, that
Pluto was one of a larger population out there. They also know that people did do searches for both
planets and planetoids, all through from the 30s to the 70s (ending with Kowal's survey that found
the first Centaur, 2060 Chiron).

J&L also don't seem to recognize that Pluto's discovery foretold not just the KB but also an important
new class of planets- dwarf planets.

I'm very surprised to hear that Pluto was considered "the last planet". I did not live at the time Pluto was discovered, but my impression was that as soon as Pluto was discovered, the hunt was on for "the tenth planet" -- people wanted to find additional planets out there. Certainly, by my childhood (several decades ago now), the possibility of finding a tenth planet was much discussed.

Having spent much of my life anticipating the discovery of a "tenth planet" (only to be repeatedly disappointed), I was very excited by the discovery of Eris; and much let down to have it ruled "not a planet" by virtue of semantic legerdemain. That is an emotional rather than a scientific reaction; but in a dispute so largely devoid of scientific criteria, I see no reason why it should not be taken into account.

[Greg Hullender]

I was a freshman at Caltech in 1977 when Kowal announced the discovery of a "tenth planet in our solar system." As with Eris, I remember that there was a big debate over what to call it -- too small to really be a planet, but in the wrong place to be an asteroid, so for a long time it was just called "Kowal's Object."

What really sticks in MY mind is that around Spring 1978 I asked a Senior Astronomy student if they'd ever decided what Kowal's Object was. He told me "I think Kowal's object is to be famous for nothing." On a more serious note, he's the one who sold me on the term "planetoid."

So somewhere around Summer of 1978 (I think it was), when they discovered Charon, anyone could use freshman physics to show that Pluto was a good bit smaller than the moon. At that point, I thought "oh well -- it looks like Pluto isn't a planet after all -- just like Chiron."

At that point in the 70s, it seemed like everything else had gone wrong, so this might have been an easier sell back then. :-)

Anyway, for what it's worth, I'm personally just as excited to see what the "King of the Kuiper Belt" looks like as I ever was to see the "Last Planet."

--Greg

[Alan Stern]

Greg,

The problem with declassifying Pluto and other ice dwarf planets is that there is no salient
characteristic that these bodies lack that the larger planets have. Like stars and galaxies,
like many species, etc. etc., planets include dwarfs. Dynamical criteria aren't about the
bodies themselves, so much as they are about where the bodies are, so you end up
with nonsense like Earth and Jupiter not being planets were they simply far enough from
the Sun in the IAU definition. These two factors are the central reasons why so many
people are ust walking on the IAU definition.

-Alan

[marsbug]

Oh, there's a pattern for sure: things in nature exist along a continuum rather than in discrete categories

Would that line of thought lead to a continuos scale of non luminous bodies , from grains of space dust to brown dwarfs, after the style of the Hertzsprung-Russel diagram for classifieyng stars?
Edit: I don't know what the scale(s) would measure, although mass is clearly the most obvious choice, but that would put the term planet into the proper context, and make the term valid for pluto, as it has the historical and cultural significance of the other eight.

[Greg Hullender]

Alan: I know. I actually liked the cleanness of your "hydrostatic equilibrium" definition, but I thought you guys lost the moral high ground when you excluded large planetary satellites, such as Ganymede.

I do think location matters in some ways; we don't appear to get ice planets close to the sun, nor rocky ones far from it. Also, without their neighbors pulling on them, don't think Enceledus or Europa would have liquid water.

Maybe the real problem is we just can't study enough planets yet to do a good job of seeing the proper categories. I wonder if we'll ever be able to detect dwarf planets orbiting other stars . . .

--Greg

[Alan Stern]

Alan: I know. I actually liked the cleanness of your "hydrostatic equilibrium" definition, but I thought you guys lost the moral high ground when you excluded large planetary satellites, such as Ganymede.

> Greg, I never said that! I have always contended planets can orbit other planets, just
as stars can orbit other stars and galaxies can orbit other galaxies.

I do think location matters in some ways; we don't appear to get ice planets close to the sun, nor rocky ones far from it. Also, without their neighbors pulling on them, don't think Enceledus or Europa would have liquid water.

> Yes, but this is only about planet *types*-- not the root issue of planethood.

Maybe the real problem is we just can't study enough planets yet to do a good job of seeing the proper categories. I wonder if we'll ever be able to detect dwarf planets orbiting other stars . . .

> That is for sure but in our solar system, we do see the pattern: small planets dominate
the planetary census.

[Alan Stern]

And this news note from the front:

Date: Mon, 5 Feb 2007 19:12:50 -0500
From: "Cheng, Andy"
...
Cc: "EXT Stern, Alan"
Subject: FW: Clay Center Pluto Program
Parts/Attachments:
1.1 OK ~218 lines Text
1.2 Shown ~390 lines Text
2 OK 241 KB Application, "Great Pluto Debate format.pdf"
----------------------------------------

FYI -- I participated in this event on Feb 4 (Super Bowl Sunday).

Attendance was about 200 people. A vote was taken at the end by show of hands, and our side (Pluto
is and should be a planet) appeared to be the winner. Owen Gingerich was the moderator, Kelly
Beatty announced that he was neutral, and the other side was led by Brian Marsden and Gareth
Williams. (An organizer) said that he changed his mind (to our side) after the debate.

Cheers, Andy

_____________

[nprev]

I too changed my vote for Pluto as a planet, but purely within the historical context as described in a previous post...Pluto should be the last planet.

What I think will probably happen over the next few decades is that we'll find numerous Pluto (or even Mars)-sized or better bodies quite far out...maybe still within the Oort Cloud, maybe not. In any case, when we're talking objects with solar orbits measured in tens of thousands of years or even much, much more, we enter a situation similar to the irregular outer satellites of gas giants: how stable are these orbits over the lifetime of the Solar System? Their gravitational association with the Sun is tenuous at best, possibly could be easily disturbed by close stellar approaches over geological time, and it will almost be certainly questionable whether some of them formed from the original solar nebula at all.

True, this issue (if it's valid) probably will not arise for some time. Still, it's worth thinking about in terms of this particular debate.

[mars loon]

And this news note from the front:
Date: Mon, 5 Feb 2007 19:12:50 -0500
From: "Cheng, Andy"
Subject: FW: Clay Center Pluto Program
Attendance was about 200 people. A vote was taken at the end by show of hands, and our side (Pluto
is and should be a planet) appeared to be the winner.

More news from the Pro Pluto front:

I have been collecting hundreds and hundreds of signatures on a petition to "Save Pluto as Planet" at all of my astronomy outreach lectures to groups ranging from astronomy clubs to schools. There is no shortage of people willing to sign, and there is no shortage of dissapointment at this short sighted ruling by a very narrow band within the IAU

The sentiment is overwhelmingly Pro Pluto

and here is a link to an article about the Clay Center Pluto Program sent to me by an attendee:
http://boston.metro.us/metro/local/article...Pluto/6796.html

and a few excerpts below.

ken

------

Crusading for Pluto
by tony lee / metro boston

FEB 5, 2007

BROOKLINE: Nearly six months after it was thrust from planetary status, Pluto remains a hot topic among experts, some of whom gathered yesterday at the Clay Center Observatory as part of International Save Pluto Day.

It’s clear that the struggle surrounding the icy mass is far from finished.

“I feel strongly that Pluto should remain a planet for historical and cultural reasons,” said Andrew Chang, of the New Horizons Mission to Pluto, which should send back the first data ever received from Pluto in 2015.

Since its discovery in 1930 by Clyde Tombaugh — who would have turned 101 yesterday — until last August, Pluto stood as the last and smallest of the nine planets.

A ruling by the International Astronomical Union (IAU) determined that an object cannot be a planet if it has not cleared its orbit of all other objects, which Pluto has not.

“I have basically always felt that Pluto was the oddball,” said Gareth Williams, associate director of the Minor Planet Center and one of the dissenters on yesterday’s board.

When asked by debate moderator Owen Gingerich, Harvard professor emeritus of astronomy, of their opinion on the matter, the crowd of nearly 200 was largely in favor of Pluto remaining a planet.