"Pluto is dead" - Mike Brown, It's official Options

[SigurRosFan]

- BREAKING NEWS: Pluto Demoted, No Longer a Planet

- Pluto loses status as a planet

[ugordan]

Quick! Is there still time to redirect New Horizons to say... Uranus or Neptune?

Sorry, I couldn't resist...

[SigurRosFan]

What's Alan's email address?

[djellison]

Why would this affect NH in any way, shape or form.

Pluto is still Pluto. Still fascinating, still unexplored, still part of a collection of bodies that we need to learn about.

The silly thing about this entire episode is that it's making the news......but no one has learnt anything, no one has discovered anything, nothing has changed.


Doug

[Ames]

The silly thing about this entire episode is that it's making the news......but no one has learnt anything, no one has discovered anything, nothing has changed.
Doug

Oh I don't know about that. As the saying goes “There’s no such thing as bad press”

The public has learnt that that the Solar-system is a much more varied and interesting place than that taught to them in school (25 years ago in may case ) and highlighted the problematic discoveries of large bodies that don’t conform to the old rules.

I think it's fascinating, and I think the correct decision has been made.

I am also glad that NH is on it’s way (Phew!)

Nick

[Paolo]

I am quite happy of the decision because
1) the definition of planet that was approved is exactely the same I have been promoting for some time
2) New Horizons is already launched. I wonder how more difficult it would have been to "sell" the mission had Pluto already been demoted

[Rob Pinnegar]

The silly thing about this entire episode is that it's making the news......but no one has learnt anything, no one has discovered anything, nothing has changed.

...Which makes it perfectly suited for making the news.

And yes, we *are* lucky that New Horizons is already launched. It's hard to see how Pluto's demotion from planetary status could have failed to affect the mission, had this happened a few years ago.

[ugordan]

Why would this affect NH in any way, shape or form.

It shouldn't. I was joking -- hence the smiley.
Although I am one of those "demote Pluto" guys, I still think Pluto is a worthy target to explore. I'm eagerly awaiting July 2015 as much as the next guy. Just as I'm looking forward to Dawn visiting Ceres and Vesta. To me it makes very little difference what the object's classified. As long as it's interesting, I wanna see it explored.
That's why this whole thing is silly and absurd as you say; I was just trying to lighten things up a bit

[David]

Just wait until Senator Curmudgeon (C-New Dorkshire) stands up in Congress and demands that New Horizons be "recalled" because "the people of this great nation don't want to see their tax dollars wasted sending machines to 'dwarf planets'!"

[Guest_Myran_*]

We discussed this earlier, and this triggered a conversation with one friend with a nice astronomical interest some time later (He's not a full fledged space buff, but well infomed).
And his view was already then that Pluto should be demoted for the simple reason that Pluto cross the orbit of Neptune.
As for me I kept the view that Pluto should remain a planet for 'historical reasons' even though my hesitation had grown somewhat. I think I had a problem of demoting a planet since I have grown up with the idea that Pluto are one planet.

Now the verdict are in, I live with it. Pluto are still there, whatever it is called. Yet like some already have hinted, it might have been hard to get a mission underway if Pluto was not seen as part of the planetary family. So its the best of both worlds..... Pluto and Charon thats it!

[JRehling]

...Which makes it perfectly suited for making the news.

And yes, we *are* lucky that New Horizons is already launched. It's hard to see how Pluto's demotion from planetary status could have failed to affect the mission, had this happened a few years ago.

I disagree. It was a long, slow fight to get a Pluto mission, and I don't think anyone involved would want to have any extra ammunition whatsoever in the hands of the political opponents of it.

I could see someone in a House committee saying, "The damn thing's not even a planet any more," getting a round of laughs, and a representative or two thinking that the same line would seem persuasive to a few voters or fundraisers, etc. Or Goldin pushing the same line. I don't see the impetus towards the mission having been so solid that it might not have been derailed by an additional flyspeck of resistance.

NH has 9 years to go. I would be very surprised if this issue remains settled. Anticipation of NH's arrival itself might spur reconsideration of the issue. It's credible that NH's observations might rekindle the issue if Pluto is found to be particularly lively.

If the scads of rival definitions has made anything clear, it's that "planet" is a category with many properties that one person or another finds to be relevant in its conceptualization. Most of the reasoning that has gone into the debate has involved appeals to intuitions: Gut-level reactions to hypothetical cases have been used repeatedly as the test of a definition. If this tells us anything, it should be that the gut-level reaction is the real definition of "planet", and we're just trying to reverse-engineer it into a codification. We all know that Saturn and Mars are planets, and we pretty much all "know" that Charon isn't. When we get a definition that counters what we "know", we reject it. Again, what we already "know" *is* the definition of planet, and there's no guarantee that it codifies elegantly. As the Supreme Court justice said of pornography vs. art, you know it when you see it. Of course, different people have different opinions. That, to me, is the end of the line. The embarrassment and the indecision shows that it was a damaging exercise that missed an opportunity to do the right thing and NOT define the undefinable. And this issue is not settled, I promise.

[centsworth_II]

...no one has learnt anything, no one has discovered anything, nothing has changed.

Discovery also includes better understanding what you already "know". This discussion could be a good way of letting the general public see some of the behind the scenes workings of science. Like a tour through a slaughterhouse to show the messy reality behind the neatly wrapped meats in the grocery store, this shows the messy reality behind the neatly wrapped scientific "facts" in school books.

[RNeuhaus]

And now what astro category belong to Pluton? Icy Asteroid?

P.D.
Never mind. I have already read others pages: --> Dwarf planet. It does not sound me good! because its nomination is the same: Planet.

Rodolfo

[djellison]

This discussion could be a good way of letting the general public see some of the behind the scenes workings of science.

This isn't science though. We have not measured the composition of anything, nor have we found something new. We've not measured an albedo, taken a spectra, imaged an occultation......it's just administration.

And to be honest, given that 2 weeks ago we had 9 planets, 1 week ago we had 12 or more, and now we have only 8.....it's made the scientists involved looked more than a little silly.

Doug

[punkboi]

Discovery also includes better understanding what you already "know". This discussion could be a good way of letting the general public see some of the behind the scenes workings of science. Like a tour through a slaughterhouse to show the messy reality behind the neatly wrapped meats in the grocery store, this shows the messy reality behind the neatly wrapped scientific "facts" in school books.

Look on the bright side, with only 8 planets now... Our exploration of the solar system is officially complete! USA! USA! USA! Just kidding.

[um3k]

Look on the bright side, with only 8 planets now... Our exploration of the solar system is officially complete! USA! USA! USA! Just kidding.

No, no, it's not complete until all the planets have had orbiters!

[volcanopele]

grrr.... needless to say I am very unhappy right now. I'll live, but still

I'll see if www.demoteearth.com is still available.

[JRehling]

This isn't science though. We have not measured the composition of anything, nor have we found something new. We've not measured an albedo, taken a spectra, imaged an occultation......it's just administration.

And to be honest, given that 2 weeks ago we had 9 planets, 1 week ago we had 12 or more, and now we have only 8.....it's made the scientists involved looked more than a little silly.

Doug

I completely agree.

Several years ago, I stated the opinion that it is a mistake to think that doing science is hard but naming things and defining categories is easy. In this case, none of the "science" is particularly sophisticated: You could teach an intelligent person with no science background all of the relevant science in at most a few hours. This is very different from the debates around biological taxonomy, which pertain to encyclopedic arcana.

I would have put this issue to professional categorists, cognitive scientists to wit, instead of professional astronomers.

In a business, you learn that professionals in area X really are better at it than smart people who are dabbling in area X. A smart engineer should not take over a sales job. A smart marketer should not install computer hardware. I think what we've seen here is that being smart at astronomy doesn't make someone a good categorist. I think if the "facts" and position-papers supporting three to ten rival definitions had been handed to people who study categorization, they could have rendered an elegant embarassment-free definition that the scientists themselves could not. They were basically operating in an area outside their expertise: Astronomy has had an easy time of it, distinguishing between white dwarfs and neutron stars, neutron stars and black holes: distinctions that are sharp and clear. The first outing in a really tough categorization task has shown the lack of experience.

[centsworth_II]

USA! USA! USA! Just kidding.

I read that Pluto was the only planet discovered by an American.

[centsworth_II]

This isn't science though. We have not measured the composition of anything, nor have we found something new. We've not measured an albedo, taken a spectra, imaged an occultation......it's just administration.

This whole discussion has opened up precisely because of how many new things have been discovered about the solar system. Science is not just the collecting of data, it is also putting the data in context with what is already known.

Like the classification system of living things has changed with new genetic studies, the classification of solar system objects must change with new discoveries. In neither case will the changes be quick, easy, static or uncontroversial. But in both cases, the classification discussions are very much part of the science.

[Toma B]

Well, I'm personaly not very happy about losing Pluto as planet but at least I can say that I have saw all 8 planets with my 4,5" telescope...
I'm just guesing what size asteroid (or whatever) has to be to be planet...because when Pluto was discovered it was thought it is 6000 km in diameter, and that would be a planet!

[David]

And now I have to update my rhyme:

As for Pluto, Sir or Madam,
Fame and glory, it has had 'em
But it's gone the way of Adam --
Wasn't good enough for me!

Gimme that Old Time Solar System
Gimme that Old Time Solar System
Ceres, Pluto -- never missed 'em
They're not good enough for me!

[djellison]

B)-->

.because when Pluto was discovered it was thought it is 6000 km in diameter, and that would be a planet! [/quote]

No it wouldn't.....it's neighbourhood would not be cleared so it wouldn't be a planet.

Unfortuantely, the same is true of almost every 'planet' in our solar system...so this definition has written of most of the planets we have. I'm unsure of how many Venus and Mercury crossing asteroids there are...but at the moment I think we've got about 3 planets by this definition.

Doug

[JRehling]

B)-->

Well, I'm personaly not very happy about losing Pluto as planet but at least I can say that I have saw all 8 planets with my 4,5" telescope...
[/quote]

Yeah! I will add that I saw all of them in one night, and I made the observations of increasing distance from the Sun, with the Moon inserted into the sequence. Had to stay up mighty late to do it.

[RedSky]

I read that Pluto was the only planet discovered by an American.

Yep... Clyde Tombaugh discovered it in 1930 from Arizona. Throughout the 1920's, there had been a lot of hype in the U.S. public print media about "the search for Planet X". It was suspected because of supposed perturbations seen in Neptune's orbit that another outer planet should exist. Clyde knew after the discovery that it could not have been the Planet X they were looking for... it was too small to be responsible for the Neptune perturbations. (which later observations resolved away any large discrepancies in Neptune's orbit, so in fact, they were searching in vain).

Actually, the only people with any justifiable emotional connection with Pluto and its status should probably be Percival Lowell (of the infamous "canals on Mars" ordeal), Clyde Tombaugh, and perhaps, Walt Disney ... and I doubt right now that they care. The true person who pushed for the search was Percival Lowell, who employed Clyde at his observatory near Flagstaff, AZ for the main purpose of searching for "Planet X".

If there hadn't been all the hoopla of "looking for Planet X" and the "name the new planet" hype afterward... the 1930 discovery would probably have been barely noticed except for a mention of "asteriod found on the edge of the solar system in highly inclined orbit". But, as it was, with all the hype, Percival Lowell got his claim to fame... since the selection of the winning name of Pluto officially has as its symbol an overlapping "PL"... his initials!

[David]

If there hadn't been all the hoopla of "looking for Planet X" and the "name the new planet" hype afterward... the 1930 discovery would probably have been barely noticed except for a mention of "asteroid found on the edge of the solar system in highly inclined orbit".

I don't believe that's at all true. In the context of 1920s astronomy, minor planets (asteroids) were defined by their position inside Jupiter's orbit. There was no term other than "planet" available to describe Pluto at the time, as it certainly was not a comet or a meteor. Pluto was also initially (and for several decades) imagined to be at least the size of Earth. Someone who described Pluto as an "asteroid" in 1930 would have looked ridiculous. Regardless of the inclination of its orbit (which is, for most people, a pretty esoteric detail), any object beyond Neptune that was bright enough to be detected in 1930 would have been dubbed a planet.

The importance of the "Planet X" search has nothing to do with "hype", but rather the fact that without the Planet X search Pluto would not have been discovered at all in 1930, and probably not for another six decades.

[Guest_JamesFox_*]

Well, I don't really minf the intent to divide things into the 8 regular planets, dwarf planets, and all others, but I think the given definition is screwey. They should have used the vague, but more appropriate term 'orbital dominance'.

[odave]

I will add that I saw all of them in one night...

...and I'm relieved that I don't have to try for "Xena" now - can't afford that kind of equipment!

[punkboi]

...and I'm relieved that I don't have to try for "Xena" now - can't afford that kind of equipment!

All I can say is... The New Horizons website will have a couple of revising to do...

[Paolo]

I read that Pluto was the only planet discovered by an American.

Speaking of which, the Italian television has just aired a news story about Ceres' discoverer Piazzi and his small town of birth some 100 km from here (Milan)

[Holder of the Tw...]

Like JRehling, I predict that shortly after July 2015, at the latest, we will be posting a "Pluto is resurected" thread here.

[ElkGroveDan]

I predict that popular culture will continue to speak of "the nine planets" and the "planet Pluto". As someone said on a previous topic, the whole concept of the nature of a planet has been largely cultural and linguistic one anyway.

My experience is that "official" attempts to dictate changes in time-honored concepts and traditions often fall flat (outside of totalitarian dictatorships, that is). I recall that in the 1970s "everyone" was of the view that the US should switch to the metric system. President Carter even went so far as to issue executive orders dictating the use of metric measurements in all things related to the US government. The transition began, but it never stuck. I used to have a 1980 Oldsmobile that required two sets of socket wrenches, metric for the body and English for the engine.

The point is that the movement never stuck in US culture and eventually everything reverted back to our English standard (with no commentary from this former engineer as to which system is "better.") I believe the same will happen with this decision on "the Planets." Lacking any kind of "enforcement" school teachers will keep their expensive models and collections of elementary textbooks. This news will fade in about three days, and a month from now the average disinterested members of the public will forget that it ever happened.

[djellison]

I predict that popular culture will continue to speak of "the nine planets" and the "planet Pluto".

I know I will.

That - or accept a set of definitions that technically remove planetary status from just about every planet in the solar system.

Doug

[David]

This news will fade in about three days, and a month from now the average disinterested members of the public will forget that it ever happened.

Yes, but there are always going to be officious up-to-date people who will undertake to "correct" them if they happen to speak of "nine planets". The worst are going to be the smart-alec kids who will raise their hands in 4th grade and say, "Excuse me, Miss Barringer, but astronomers now say there are only eight planets." You know, kids like you and me when we were that age.

[JRehling]

Yes, but there are always going to be officious up-to-date people who will undertake to "correct" them if they happen to speak of "nine planets". The worst are going to be the smart-alec kids who will raise their hands in 4th grade and say, "Excuse me, Miss Barringer, but astronomers now say there are only eight planets." You know, kids like you and me when we were that age.

This is why I thought the "biggest" thing the community could have done here is to have the "official" word be: "Don't be officious about this. It's inherently vague. Some things are."

By making headlines one day and contradictory headlines a few days later, the community perpetuates the unfortunate perception that officiousness is a big part of science.

[ElkGroveDan]

Yes, but there are always going to be officious up-to-date people who will undertake to "correct" them if they happen to speak of "nine planets".

Let's not forget the quiz-show contestants who will now lose the whole pot of cash by answering, "There are NINE planets, Regis."

[yg1968]

Alan Stern isn't too happy about all this. See this article:

http://www.space.com/scienceastronomy/0608...definition.html

[Stephen]

Oh I don't know about that. As the saying goes “There’s no such thing as bad press”

Oh I don't know about that. The whole episode would seem to give a whole new meaning to the term "mad scientists".

======
Stephen

[Stephen]

Yes, but there are always going to be officious up-to-date people who will undertake to "correct" them if they happen to speak of "nine planets". The worst are going to be the smart-alec kids who will raise their hands in 4th grade and say, "Excuse me, Miss Barringer, but astronomers now say there are only eight planets." You know, kids like you and me when we were that age.

Unfortunately a more likely scenario is that some kid will get up in class one day and say: "Excuse me, Miss Barringer, but my pop reckons there are nine planets. So why did you mark me wrong in the exam?"

If the textbooks change sooner or later all the kids will start talking about eight planets. They will certainly be required to answer "eight" or be marked wrong.

Something like that happened in Australia to what used to be called "Ayers Rock" until the powers-that-be decided it would be more politically correct to rename it "Uluru".

======
Stephen

[Greg Hullender]

I still very clearly remember a teacher who insisted Saturn had 9 moons because that's what our 1950's-era textbook said, and who was unmoved by any other evidence. "Don't believe everything you read" was his catch-all response.

Reading the occasional AAAS article on the subject, I don't think American science teachers have gotten much better in the past 35 years. So I'd expect the kids to be more up to date.

That said, this has had so much publicity that even the lamest teacher can't have missed it. Even my guy read the daily paper. I shudder to think how he'd have explained this, though.

[JRehling]

I still very clearly remember a teacher who insisted Saturn had 9 moons because that's what our 1950's-era textbook said, and who was unmoved by any other evidence. "Don't believe everything you read" was his catch-all response.

Reading the occasional AAAS article on the subject, I don't think American science teachers have gotten much better in the past 35 years. So I'd expect the kids to be more up to date.

That said, this has had so much publicity that even the lamest teacher can't have missed it. Even my guy read the daily paper. I shudder to think how he'd have explained this, though.

I got to thinking about how much total time a child will hear about the solar system in a K-12 education, and how much of it will now be devoted to talking about this stupid planet definition issue, and what information that waste of time will displace. Chances are, the child will not hear about dust devils on Mars... but will hear that Pluto is really small. They won't hear that Jupiter has huge lightning storms, but they'll hear that astronomers voted on what is a planet.

I'm less concerned that a teacher will explain this matter "correctly" than that it will waste class time at ALL. I'd say if you had ten-minute blocks of lessons, and you wanted to correctly place the importance of this issue, it would be somewhere past #500, but instead it's going to end up in the top ten. And instead of a kid getting the idea that beautiful, exciting, dynamic, landscapes are out there, they'll get the idea that there are rules and definitions that must be adhered to. It's a tremendous shame.

[odave]

IIRC, my 3rd grade daughter's class spent about a week of their science time on the solar system last year. Since it's been all over the media, questions are bound to come up, so unfortunately it should be covered. Depending on how the teacher wanted to handle it, they could probably get through the discussion in 10-15 minutes. That may blow half of a day's science lesson, but you've still got the rest of the week for more important things.

[Stu]

Depending on how the teacher wanted to handle it, they could probably get through the discussion in 10-15 minutes.

Hmmm... 10-15 minutes to explain how Pluto was predicted, then found; how astronomers looked for then found KBOs; how there was a worldwide astronomical debate, lasting decades, about the identity of Pluto, at the same time as small group of planetary scientists fought desperately for NASA to send a mission to Pluto, and succeeded in launching it just before a visionary and controversial proposal was put forward to expand the solar system, which was then shot down and replaced with what many see as a painfully politically-correct compromise that in turn led to a suspiciously undemocratic vote which finally ended with Pluto being evicted from the list of planets, to the disgust and outrage of many...

If I heard from my kid that a teacher had raced through all that in 10-15 minutes I'd want them slapped with a wet fish and made to do the lesson again.

[JRehling]

If a school does spend a total of 5 hours on the solar system, even 15 minutes for Pluto's planet status is way too much. That's 5% of the total time. Here are nineteen things that deserve mention:

Sun, Mercury, Venus, Earth, Moon, Mars, Asteroids, Meteors, Jupiter, Io, Europa, Saturn, rings, Titan, Uranus, Neptune, Triton, Pluto-Charon, comets.

Granted, some of these things will get a brief mention only, but Mars and Titan among others could be topics dealt with at length.

Space exploration itself could eat an hour. The planet-status topic is going to bump something far more worthy off the list.

[Big_Gazza]

Yeesh! Too much concern over a non-issue. Anyone would think that the government has re-introduced prohibition from all the doom and gloom.

Folks, lets get it into perspective. The world hasn't changed. Tomorrow the price of petrol will be the same, the taxman will be just as greedy, the government will just as incompetant, and women will still defy understanding

Pluto is where it belongs. The flag bearer for the little guys. The icy rocks that never amounted to much. Its not a real planet, but it took us 7 decades to realise that.

Consider the alternative. The year is 2360, and little Johhny is having trouble remembering the names of the planets. He is OK until he gets to the double planet of Brangelina & Tomkat at 57 AU (number 31 in the list) but it gets hazy after that. He gets frustrated, gives up on school, and drifts into an aimless life of vice, crime and illegal drug use, forever haunted by the infamous decision by the IAU in 2006 where sanity just did not prevail.

[Bill Harris]

My opinion? They are loonies.

There may be good logic for not designating the KBOs and other minor Solar System objects as planets, but Pluto ought to be a special case since it was discovered and named in the pre-interplanetary probe era and should be "grandfathered" in.

My 2c.

--Bill

[ugordan]

Pluto ought to be a special case since it was discovered and named in the pre-interplanetary probe era

So was Ceres.

Geez. this debate will never end, for as long as Pluto exists. Therefore, I suggest we blow it up. No Pluto, no problem.

[Stu]

If a school does spend a total of 5 hours on the solar system

You see, this is the problem, right here. We're all happy with the idea of a school spending just 5 hours teaching about the solar system. 5 hours! That's NOTHING!

I wasn't suggesting for a moment that the Pluto-related items I listed should be taught at the expense of other astronomical subjects, phenomena and places, far from it. I was trying to say that astronomy is such a huge, huge subject that every planet deserves more than a mere "10-15 minutes". Jeez, I spend whole mornings and afternoon running junior school workshops about the solar system, and have to force myself to keep Mars' section under control as I could easily spend the whole session just talking about Valles Marineris!

This is a real "grrrr!!!" of mine, the quality of science education in schools. I can only speak from experience of schools over here in the UK, but "space" is taught appallingly, almost non-existently. There are token efforts made to cover the subject, at best. If the Pluto debate is the catalyst for improving that then yaaaay, I'm all for it. I just worry that what's more likely is that teachers - those that can be bothered - will take the debate as a sign that Pluto's not even worth bothering with to astronomers, and sweep it under the carpet, dismissing it as an iceball.

[odave]

Hmmm... 10-15 minutes to explain how Pluto was predicted, then found...

I was thinking of 8-10 year old elementary students, so the classification discussion doesn't have to be quite so detailed. I totally agree with that even that's too much to spend on this matter, but the cat's out of the bag. I'll be paying closer attention than normal to what happens in class when space comes around again this year. I'm sure the better teachers will make an effort to balance the time on the issue and "get it right", but unfortunately I feel a majority of them will teach straight from the book, or worse, straight from the standardized test.

And kudos to Stu for doing those workshops! I've done several astronomy nights myself, and I've always found the students & teachers very appreciative of the extra exposure.

[alan]

Geez. this debate will never end, for as long as Pluto exists. Therefore, I suggest we blow it up. No Pluto, no problem.

DON'T DO IT

If that much plutonium (1.3 * 10^22 kg) was detonated it would release 10^36 Joules. More energy than the sun produces in 88 years.

[Guest_Myran_*]

ugordan wrote: So was Ceres.

Thats correct, Ceres was declared to be a planet at first. One reason for that was that it fitted in the right slot for the idea of the now defunct 'Titus-Bode law'. But also that the size wasnt known.

So
1: Demoting one object of the planet label have been done before.
2: It happened when the true size of the object began to be obvious.

The same happened to Pluto in a step by step process after Charon had been discovered. The estimated size was downgraded and after the set of eclipses we had a the size nailed down.

Yet I agree with Bill Harris that we might have been able to keep Pluto, I would have liked that personally. The only good point I have for that is that Pluto are inside the actual belt of KBO's, but little other pro's. The list of cons starting with the elliptical Neptune crossing orbit & out of the ecliptic gets uncomfortably long - so its not about logic or facts but only 'sentimental' reasons.

Now what if someone actually do discover lets say one object in or close to the plane of the ecliptic and a near circular orbit & 5000 km diameter out there?
Well even I would give up my stance about that one not might be one KBO's that makes up same belt and depending on how many ways it qualify have to say that it instead are a never finished protoplanet or actual planet embedded in same belt.

[MCS]

So was Ceres.

Geez. this debate will never end, for as long as Pluto exists. Therefore, I suggest we blow it up. No Pluto, no problem.

If only there were a handy Death Star around:

"Foolish earthlings, quibbling over such trivial matters. I will settle this argument for them. Permanently."

It would keep astronomers busy cataloguing all the new KBOs!

[ugordan]

If only there were a handy Death Star around:

That's easy -- I wonder if Mimas can be reactivated after being unused for such a long time. We all know it's not actually an ordinary moon of Saturn...

[Bill Harris]

>The same happened to Pluto in a step by step process after Charon had been discovered.

Yes, and Pluto has been teetering on the fence for a while as folks considered it to be an escaped moon of Neptune.

--Bill

[tasp]

Am I alone in wondering why this IAU edict is even happening in this time frame?

Pluto has been on the planet roster for a very long time now, could this matter have been tabled till after the New Horizons flyby?

If Pluto turns out to have geysers, weather, climate, tectonics, lakes, volcanoes, lightning, aurorae, rings, hurricanes, magnetic field, etc. perhaps there would be a new debate regarding what a planet is?

[ugordan]

If Pluto turns out to have geysers, weather, climate, tectonics, lakes, volcanoes, lightning, aurorae, rings, hurricanes, magnetic field, etc. perhaps there would be a new debate regarding what a planet is?

Titan likely has most of those things, but I don't see such a fuss pushing for it to be a planet. I don't think interestingness should be a factor in determining what is a planet. Nor do I think being a planet should be a factor determining if something's interesting.

[David]

Titan likely has most of those things, but I don't see such a fuss pushing for it to be a planet.

You haven't been listening to Jason!

[ugordan]

You haven't been listening to Jason!

Nah.. He also hates Europa, so go figure!

[Jeff7]

I just worry that what's more likely is that teachers - those that can be bothered - will take the debate as a sign that Pluto's not even worth bothering with to astronomers, and sweep it under the carpet, dismissing it as an iceball.

Too many of those teachers are probably completely unaware that Pluto has its very own flyby mission en route.

If only there were a handy Death Star around:

"Foolish earthlings, quibbling over such trivial matters. I will settle this argument for them. Permanently."

It would keep astronomers busy cataloguing all the new KBOs!

But the Empire would only be interested in blowing up Charon.

>The same happened to Pluto in a step by step process after Charon had been discovered.

Yes, and Pluto has been teetering on the fence for a while as folks considered it to be an escaped moon of Neptune.

--Bill

The other half of the proposed Triton duo perhaps? What I refer to is of course the theory that Triton was a wandering object, with a partner, and when they got too close to Neptune, Triton was captured while the other one was flung away.

[Guest_AlexBlackwell_*]

Mike Brown is the guest for the latest edition of Planetary Radio.

[djellison]

He even said that there is every chance we will find something the size of Mars or even Earth..but we'll have to call it a dwarf planet.

That's just astonishingly short sighted.

Doug

[volcanopele]

He even said that there is every chance we will find something the size of Mars or even Earth..but we'll have to call it a dwarf planet.

That's just astonishingly short sighted.

Doug

See, that to me, sums up why I really dislike this definition. Personally, I don't think it is THAT big of deal whether or not Pluto remains a planet, but in the attempt to remove Pluto, they have shut the door for all intents and purposes on the possibility of finding planets in the cold deep. And we aren't just talking about problems for Mars and Earth-sized objects, even larger objects far out would have problems clearing their neighborhoods as go farther out.

[djellison]

I to don't really care if Pluto is or isn't a planet...but I DO care when the definition they've come up with is so flawed and counterintuitive.

Doug

[climber]

Now, in the books, NH will be seen as a new class of explorer
We have had :
Spoutnik 1 to the Earth
Luna 1 to the moon
Mariner 2 the first to a planet
Pionner 10 the first to (outside planets and) outside the solar system (may be Voyager 1's better pick)
Giotto to a comet
...you can complete the very limited list of "new explorers"
In that sense, its very name "New Horizon" couldn't have been a better choice. I personaly don't mind whether Pluto is or isn't a planet, I want to understand our solar system and how it compares to others. Go NH, Go, tell us what's up there.

[jamescanvin]

He even said that there is every chance we will find something the size of Mars or even Earth..but we'll have to call it a dwarf planet.

Yup, that's been my other big problem (after the whole neigbourhood clearing issue) with all this.

Dwarf Planet: Not necessarily a dwarf and definitely not a planet. Talk about confusing. Worst name ever!

[gpurcell]

My wife tolerates my space exploration obsession, teasing me about going to JPL websites and the like. She's your basic, educated person for who space is at most a passing thought.

This Pluto thing got her pissed off enough to rant about it. Which is surprising.

Her beefs:
1) What the heck is the "IAU" and who gave them the authority to determine something like this?
2) Historical precedence ought to count for something.

Getting her riled up is an indication of how foolish this decision was.

Now, I'm not an astronomer. But I am a political type, and from my professional perspective this issue was handled incredibly poorly.

First, the IAU did not have to create a set of exclusive definitions. Doing so ensured that the Pluto decision would be a hardball choice over which there could be no compromise. That's a bad situation to be in. The original committee suggestion was quite clever in this regards; by keeping Pluto a planet, while including it in a separate category, the path was laid out for the gradual elimination of it. Without a fight. As the planets of the KBO proliferated, the shorthand would have become: "We have eight classical planets and ### "plutons" beyond Neptune of which we know the most about Pluto." In a generation or two, Pluto and the rest of the planets are separated.

Second, the whole rejection of the committee report was a really bad scene. It looks like a cabal of anti-Pluto types threw out a lot of serious work and imposed their policy preferences over the vocal objections of a significant minority. The small group that actually voted on this only adds to the sense that Pluto was convicted in a kangaroo court.

Third, and this bears on my wife's first point: the IAU has nothing but its internal credibility behind its decisions. By engaging in a hack job on this issue, that credibility has been undermined significantly. That lack of credibility is likely to bear noxious fruit in a host of policy choices: "Well, you all can't even decide what a planet is, when any sixth grader can tell you that! So why should this Congress give you more money?"


In summary, it was exceptionally foolish to allow astronomers, untrained in linguistics, semantics, or politics to have free reign in determining the answer to the Pluto question. The IAU obviously realized this with its initial committee selection. It is most unfortunate that the professional anti-Pluto crowd did not take their advice into account in favor of their ill-considered jihad.

[mars loon]

He even said that there is every chance we will find something the size of Mars or even Earth..but we'll have to call it a dwarf planet.
That's just astonishingly short sighted.

quote:Today, 07:28 PM
I to don't really care if Pluto is or isn't a planet...but I DO care when the definition they've come up with is so flawed and counterintuitive.Doug

I completely agree and even Mike admits on his website that the definition is flawed.

This is a complete PR disaster for astronomy and science as evidenced by the endless cartoons, polls, etc. So now the public will have even less respect for scientists. As a scientist, I dont see much positive here for science or public understanding of science.

gpurcell's wife is typical of public reaction.

The IAU vote should have tabled this for a later date, given all the internal controversary. Doing nothing or trying again to reach broader consensus would have been better than being hijacked at Prague by a narrow band.

[mchan]

The original committee suggestion was quite clever in this regards; by keeping Pluto a planet, while including it in a separate category, the path was laid out for the gradual elimination of it. Without a fight. As the planets of the KBO proliferated, the shorthand would have become: "We have eight classical planets and ### "plutons" beyond Neptune of which we know the most about Pluto." In a generation or two, Pluto and the rest of the planets are separated.

I had thought this as well but did not post it in such a clear and succint way. The effects of the original proposal would indeed be spread out and evolve over time. Even the cultrual planet might diverge from the scientific planet, with Pluto being a cultural planet and not a scientific planet.

[karolp]

Even the cultrual planet might diverge from the scientific planet, with Pluto being a cultural planet and not a scientific planet.

And how about having "cultural" bacteria versus "scientific" bacteria? Or "cultural" mammals vs. "scientific" mammals? All in all planet was supposed to be a scientific word. It had only become a cultural one because underfunded science cannot provide much details on what a planet really is so culture filled in.

[djellison]

To use the biological analogy 'Planet' is like 'Bug'

Bug can mean all sorts of things in common english - Bacteria, Virii, small insects etc etc.

In common english - Planet can mean Terrestrial, Gas Giant, KBO etc etc etc.

Perhaps there's an argument to be made for not trying to define the word 'Planet' at all.

Doug

[karolp]

This is a complete PR disaster for astronomy and science as evidenced by the endless cartoons, polls, etc. So now the public will have even less respect for scientists. As a scientist, I dont see much positive here for science or public understanding of science.

gpurcell's wife is typical of public reaction.

The public does not typically have much understanding of such things as the Kuiper Belt. For them that is pure technobabble. They simply know that Pluto was discovered by an American and has the same name as Disney's cute cartoon dog. They tend to run into a weird "overpersonification" of Pluto defending it from "bullies" and demanding it to be treated like "any other". It was already obvious what Pluto is with the discovery of 1992QB1 in 1992 (the first known KBO). And if that was not enough, discovering Xena - a KBO larger than Pluto did it. Mike Brown - Xena's discoverer and Kuiper Belt explorer understands that. The "public", as well as non-planetary, non-KBO astronomers - don't.

[JRehling]

And how about having "cultural" bacteria versus "scientific" bacteria? Or "cultural" mammals vs. "scientific" mammals? All in all planet was supposed to be a scientific word. It had only become a cultural one because underfunded science cannot provide much details on what a planet really is so culture filled in.

What about "river"? "Mountain"? "Canyon"? Those are all vaguely defined.

I hardly think more funding would shed a lot of light onto this. Maybe whopper projects in Earth-based telescopy to search for more far-out objects.

[gpurcell]

And how about having "cultural" bacteria versus "scientific" bacteria? Or "cultural" mammals vs. "scientific" mammals? All in all planet was supposed to be a scientific word. It had only become a cultural one because underfunded science cannot provide much details on what a planet really is so culture filled in.

I disagree. Planet was a word for a category of objects long before science came along.

Definitions are, at some level artificial constructs. There is no "scientific" answer to the question "What is a planet?" because the question itself is not one with truth value. Given a set of criteria, science can determine whether an object matches or fails...but the criteria used are, in the end, subjective.

[dvandorn]

...Planet was a word for a category of objects long before science came along.

Very true. If we want to go back to the original definition, a planet is any point of light in the sky that "wanders," i.e., that does not move in the same manner as the stars within the celestial firmament. If we go back to that definition, then any solar system object, no matter how small, that is visible from Earth is a planet.

I guess we could debate whether or not an object must be naked-eye visible to qualify...

-the other Doug

[karolp]

Very true. If we want to go back to the original definition, a planet is any point of light in the sky that "wanders," i.e., that does not move in the same manner as the stars within the celestial firmament. If we go back to that definition, then any solar system object, no matter how small, that is visible from Earth is a planet.

I guess we could debate whether or not an object must be naked-eye visible to qualify...

-the other Doug

I don't think going back to the original idea devised by the Greeks to be a good idea. All in all the word has certainly evolved and gained some scientific meaning. But the meaning is not complete as we do not know many exotic configurations which might occur in other planetary systems. And by underfunding I mean cancelling such missions as the Terrestrial Planet Finder developed by NASA. But luckily ESA has its COROT mission which is also specifically designed to hunt for exoplanets and it is due to be launched in October 2006

[David]

I consider the (apparent) fact that I am able to discuss this planetary classification issue halfway intelligently to be positive proof that it is not in any sense a scientific question.

[karolp]

I consider the (apparent) fact that I am able to discuss this planetary classification issue halfway intelligently to be positive proof that it is not in any sense a scientific question.

And it won't really be until we find out what a planet REALLY means by exploring other planetary systems and seing what they are like and might be. I particularly find any criteria of circular orbits to be inappropriate and Sol-centered - there are "jupiters" and "neptunes" in eccentric orbits around other stars. But we shall not understand what it really means to "be a planet" until we see more planets around other stars. For now it is just a "distant flavour", not insight. But we ARE intelligent enough to tell a KBO from a planet. And until COROT tells as some more or we discover an "earth" in the Oort Cloud the case appears to be settled.

[Greg Hullender]

Something I thought sounded interesting in one of Mike Brown's papers was the idea that a "planet" in a really eccentric orbit is probably a separate condensation from the original nebula, not a condensation from the accertion disk of the star. Multiple stars do indeed tend to have very elliptical orbits, so a "planet" that condensed that way would likely have one too. He alluded to a "purist" view that insists all such bodies are "stars" not planets, although he didn't sign up to it.

The implied assumption (sounds reasonable, anyway) is that anything that does form from the accretion disk will unavoidably be in a circular orbit near the plane of the ecliptic.

[alan]

The web is being rearranged to accomodate the new definition: eightplanets.org and now redirects to nineplanets.org

[karolp]

Gas giants might get eccentric orbits from interacting with each other. It was suspected Uranus was coming close to Saturn in the past in its eccentric orbit which finally resulted in its odd tilt. Circular orbits are so "Copernican". Time to embrace the 21st c.

[Greg Hullender]

Uranus and Saturn are both in less eccentric orbits than Mars. I've never heard anyone suggest that they used to be in more elliptical orbits. I HAVE heard the suggestion that they both formed further in and have gradually drifted further out, but that would have happened when the Solar System was new.

[karolp]

Uranus and Saturn are both in less eccentric orbits than Mars. I've never heard anyone suggest that they used to be in more elliptical orbits. I HAVE heard the suggestion that they both formed further in and have gradually drifted further out, but that would have happened when the Solar System was new.

Well, it basically goes like this:

"Jupiter and Saturn start out at roughly 5 and 8 astronomical units; Uranus and Neptune begin much closer to the Sun than their current positions, at about 13 and 14 AU. They stay pretty comfortably in those positions for about 100,000 years. Then, quite suddenly, that 1:2 resonance is reached. Saturn and Jupiter don't change a lot initially, but the orbits of Uranus and Neptune go nuts. They get much more eccentric, so that their orbits cross; at times Uranus even gets very close to Saturn. After about a million years, the eccentricity dies down, and Uranus and Neptune are on their way out to more distant positions in the solar system, at the same time that Saturn begins to acquire its present orbit eccentricity."

The Whole Article

[ugordan]

"Jupiter and Saturn start out at roughly 5 and 8 astronomical units; Uranus and Neptune begin much closer to the Sun than their current positions, at about 13 and 14 AU.

I have a problem with that scenario. Namely, Saturn, Uranus and Neptune start closer in than they're now.

* Saturn : 8 AU --> 9.5 AU
* Uranus : 13 AU --> 19 AU
* Neptune : 14 AU --> 30 AU

All three are gaining momentum as they move into a higher orbit. Who's losing momentum here? You can't just get it out of nothing. There has to be a pretty large object that spirals inward as a consequence. I see Jupiter stayed pretty much where it is now so no luck there.

[Alan Stern]

Uranus and Saturn are both in less eccentric orbits than Mars. I've never heard anyone suggest that they used to be in more elliptical orbits. I HAVE heard the suggestion that they both formed further in and have gradually drifted further out, but that would have happened when the Solar System was new.

Actually, the simulations show U and N get up to e=0.3 or a bit higher en route from their former closer orbits to their current ones.
This occurs just after their strong scatterings by J or S and before dynamical friction on the outer disk damps the e back down.

[Greg Hullender]

Thanks, Alan. I knew the move had to be while there was still a lot of material in the accretion disk, but I had envisioned a gradual outward spiral. I hadn't considered a catastrophic interaction, but I guess I shouldn't be surprised.

How confident are astronomers/astrophysicsts of this simulation?

[Alan Stern]

Thanks, Alan. I knew the move had to be while there was still a lot of material in the accretion disk, but I had envisioned a gradual outward spiral. I hadn't considered a catastrophic interaction, but I guess I shouldn't be surprised.

How confident are astronomers/astrophysicsts of this simulation?

Its controversial that U and N originated in the J-S zone, but the simulations of that are convincing
that if this occured, the e's got pretty high. I myself am not convinced of the entire scenario.

-Alan

[Jyril]

Isn't it that according to the theories of planetary formation, Neptune should still be in the process of forming if it formed where it is now?

[Alan Stern]

Isn't it that according to the theories of planetary formation, Neptune should still be in the process of forming if it formed where it is now?

No. I think you're confusing the fact that in many old models, Neptune could not be made for form in
the age of the solar system. It has no significant feedstock to continue forming today in any real
sense, though technically it and all the planets--including Pluto--are gaining mass because things that
they run in to "stick" owing to their high gravity.

-Alan

[Guest_Myran_*]

Alan Stern wrote: I myself am not convinced of the entire scenario.

I am not entirely convinced of this scenario either.
One detail that makes me wonder are the fact that the disc where the planets formed should have been thinner at the outer edge. Yet Uranus have got 14 earth masses whereas Neptune got 17.
But there could of course have been a thicker belt of KBO's that Neptune gobbled up when it migrated outward and so gained more mass. The KBO's are after all just that, planet bulding blocs and if there was enough of them and we smashed them together we'd end up with something quite similar to Uranus or Neptune: A small rocky core surrounded by a vast and very deep ocean and perhaps even a similar atmosphere, at least it would have the methane.
If this scenario would be correct, then Chiron and Pluto simply are the leftovers which happened to survive with Pluto in resonance with Neptune and Chiron flipping back between Uranus and Saturn.

[Julius]

This Migrating Giant theory was clearly discussed on BBC sky at night programme.While N,U and S seem to be migrating outwards,is J supposed to be moving inwards towards the inner solar system?If I understood right,interactions with KBOS seems to be the trigger of this whole migration taking place with Jupiter being the final encounter resulting in KBOS being scattered into the interplanetary space.Would this explain the presence of Phoebe at Saturn??

[Julius]

Sorry I have been away for a while!Is that THE real ALAN STERN?I have a question:Since Charon,nix and Hydra seem to have originated from impacts with Pluto,would it be reasonable to assume that we should be seeing big impact craters on Pluto,unless of course there is some process that is refreshing the surface to obliterate such major events??What are the predictions if any have been made??

[Alan Stern]

Sorry I have been away for a while!Is that THE real ALAN STERN?I have a question:Since Charon,nix and Hydra seem to have originated from impacts with Pluto,would it be reasonable to assume that we should be seeing big impact craters on Pluto,unless of course there is some process that is refreshing the surface to obliterate such major events??What are the predictions if any have been made??

THe giant collision that produced Charon, Nix, and Hydra did not leave an impact scar because it remelted
Pluto. For KBO collisions and cratering predicts on Pluto and Charon, see Durda & Stern (2000) in
Icarus; I belirve these remain the latest model calculations.

-Alan

[djellison]

I guess one could use the Earth / Moon formation as an analogy. We don't see a enormous crater on Earth from the impact that created our moon.

(and yes - that's the real Alan )

Doug

[Jyril]

Here's the link about wandering gas giants AlexBlackwell posted earlier.

[Julius]

Thanks for your feedback Alan,much appreciated.I dont agree with the 'Pluto is Dead' title to this forum.Pluto is more alive than ever.Until recently. no one could ever dream of having a probe flying toward Pluto and perhaps other KBOS.Planet or not,doesnt matter....whats in a name???

[djellison]

.I dont agree with the 'Pluto is Dead' title to this forum

I think that's the point Those are Mike Browns words - and I think the majority in this forum disagree with them.

Doug

[Alan Stern]

This thread reminds me of the old thrust and parry:

"God is dead" --Nietzsche
"Nietzsche is dead"-- God

We'll see where the planet debate ends.

[Guest_DonPMitchell_*]

I think we should vote again. Amateur enthusiasts get one vote. Professional astronomers get 2 votes, and people who have launched a probe to Pluto get 100 votes. :-)

[Alan Stern]

I think we should vote again. Amateur enthusiasts get one vote. Professional astronomers get 2 votes, and people who have launched a probe to Pluto get 100 votes. :-)

If only.

[Julius]

Planet or not,no big deal!To be honest I was not particularly keen about having the solar system numbering 13 planets as was being suggested prior to the voting.I believe that Pluto's proper place lies with the KBOs.Personally,Pluto has not been demoted or anything.My interest in NH has not dwindled .I would like Pluto to look like Triton of Neptune;Surely that would be interesting provided that NH will have 6 months of observations whereas Voyager just flew by Triton over a matter of days. Wish we had more time with Triton.Hope to be around in 2015 to see the Plutonian system.