Soon 12 planets in the solar system !

Ed wrote:
I'm leaving just as David Levy, Jim Scotti and a host of others have
already left.

To where, I wonder?

Phil

Phil Wheeler wrote:
Ed wrote:
I'm leaving just as David Levy, Jim Scotti and a host of others have
already left.

To where, I wonder?

Not to mention where from?

--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)

SkyTools: http://www.skyhound.com/cs.html
Observing: http://www.skyhound.com/sh/skyhound.html
Comets: http://www.skyhound.com/sh/comets.html

To reply take out your eye

Ed wrote:

"The sky is our oldest symbol of order and regularity in nature. Mess
with it at your own peril."


Similar words might well have been spoken to Galileo.

Phil

Greg Crinklaw wrote in news:d6f8d$44eb1795
:

wrote:
But until then, I will feel justified in calling you either completely
ignorant about the issue at hand or a demented ape.

PLONK

http://tinyurl.com/lgowm

wrote:
The problem is the practice of classifying and naming planets ("Many
astronomers call this Xena, but don´t remember this name because some
day it most likely will change").

This is why the IAU should stick to the original plan to determine a name
for UB313, not try to define what a planet is, because it is very likely not
to succeed.

Who says you shall not mention Pluto? You are missing the point.

I like to try to avoid it, because if I do I have to waste a lot of
lecture time which I could otherwise dedicate to more fascinating and
truly astronomical issues like possible bacterial life on other solar
system planets and the abundance of water on earth. I feel that if I
would talk about everything I would just overload them.

Potential bacterial life on other solar system planets would be an
interesting thing if it can be shown to exist. But when giving short talks
to 10 year old kids I would not overload them with such speculation, but
instead give them the basic facts. Today we have 9 planets, and I would
mention their names plus say something about their size etc. to put things
in perspective.

I don't see
any problem whatsoever with saying we have 9 planets in the solar
system.

What REASON do you have to say that?

Every basic astronomy book says there are 9 planets. It is very simple. You
don't need any other reason. The word is just a convention, not a scientific
truth.

I can´t see any. And that´s why
I would never say that (any more). They don´t engage me (even if they
don´t pay me) to tell lies, i.e. tell things which are obviously
untrue. However these thingamaboobs are classified, they cannot be
nine.

Oh boy. Lies?

To me, what you say directly translates into " I don't see any problem
whatsoever with telling lies".

Wel that is your problem, not mine. If I teach the kids that books are read
from left to right, will I be telling a lie? It is a convention. Some people
read books the other way (chinese, arabs). They use another convention.

Or 8.

So when do you say nine, and when do you say eight? Do you have any
system there?

Yes. As of today there are for all practical purposes 9 planets (ref all the
textbooks). If the IAU would want to solve the problem, they would simply
issue a complete list of planets and say "these are the planets, period". If
the list contained 8 planets, then fine, I would say there are now 8 planets
(but I would tell them about the change).

Even though I don´t like the idea of eight planets unless one would
call them "classical" or perhaps "traditional" planets (or something
down that line)

What's wrong with "planets" ?

because it does not adequately reflect the
revolutionary changes in our concept of the solar system with which we
have been confronted over the last years, I would certainly go along
with any solution AS LONG AS IT IS REASONABLE, i.e. not just based on
sentiments.

The word "planet" is a traditional thing and does not reflect any
revolutionary change at all. If you want to reflect a revolutionary change,
then invent new terminology for that. "plutoids" for example.

In my opinion, the discovery of UB313 isn't terribly revolutiuonary. It was
to be expected, wasn't it?

Reason is the minimum requirement in science. And teaching science
should also mean teaching reason. (On the side but related to this: I
think that it is a crying shame that most kids leave school without
ever having heard about Ockhams Principle. Ockhams Principle is the
best protection I know against believing bull****.)

The proposed definition of a planet does not stand up to Ockhams Principle
in my opinion.

a) "Because the IAU said so"
I cannot teach science as if it were a religion. I have to give
reasons. I have to explain why.

You are going to have a problem then, because you either have to tell them a
convention or go for b) below. Why do we have 7 days of the week, why not 9?

We do this every day. Look up a book on astronomy. Does it list the planets?
Is that a problem?

b) Give them the IAU resolution
You cannot seriously mean this. Do you want me to take you serious?
Because if you don´t, then why should I discuss with you?

You have understood my point. You are proposing that the IAU definition is a
sensible and useful, and scientifically correct definition, right? When I
then suggest you use the IAU definition in real life, you ask "Do you want
me to take you serious?"

Doesn't that mean that the definition is completely worthless? Scientists
don't agree with it, they call it arbitrary. If you suggest it is being used
in teaching, you will be met with the reaction "Do you want me to take you
serious?"

How is it possible to fail more?

What do you think works best?

For your benefit (and I wonder if mine as well) for the moment I will
consider this as a joke.

Not really. You dismissed both a) and b). You seem to be heading for a
problem in your next talk on planets!

It seems as if Pluto is
just as popular among kids as are dinosaurs. I don´t know why, but
perhaps it has to do with Walt Disney.

I hope you are correcting this mistaken Walt Disney idea whenever it
shows up?

The "Walt Disney Theory" is mine (well, I think I read it somewhere in
S&T as well). I believe it to be a good theory. But if you have a
better explanation for public "plutomania", I would appreciate to hear
about it. Because in this case, it can´t have anything to do with
Tombaugh.

Do you want me to take you seriously? Are you saying this while teaching
astronomy to kids?

The discovery of the planet Pluto was announced On March 13, 1930. The name
was suggested by a british girl (Venetia Phair)
http://news.bbc.co.uk/1/hi/sci/tech/4596246.stm
The name is taken from greek mythology.

The suggested name was popular at Lowell observatory, since the two first
letters match the initials of Percival Lowell.

Walt Disney's Pluto first appeard on film 18. August 1930
http://www.flensburg-online.de/comic...eys-pluto.html

Are dinosaurs and Walt Disney relevant to astronomy?

That begs the question.
Plutomania is not an astronomical but a psychological phenomenon.

It's not a question, and who is suffering from "Plutomania"? As I told you,
I am fine with both 8 and 9 planets, it is not important.

So then what do you do?

Give them the current list of planets. If Pluto is in or out, it
doesn't matter. If Pluto is demoted, then it isn't unique in
history. Ceres has been demoted before, among others. Tell them
about it, it is part of the history of the Solar System.

I suppose that what you really wanted to say is: "..., it is part of
the history of solar system astronomy". A very interesting (and
complex) subject indeed, but I want to talk about it when *I* want to,
and not because I am forced to do it.

No-one is forcing you. Just give them the list, then.

The history of solar system
astronomy goes way back in time, thus I believe that it should be
taught as a separate unit. I don´t believe in "quick and dirty".

Then teach it as a separate unit. No problem. It is unrelated to any
definition of "planet".

You mean your system of education
stands or falls on whether Pluto is a planet or not? I am surprised.

You are begging the question again.
My system of education stands and falls with whether in science things
are classified based on reason or based on sentiment. As I said above:
"...teaching science should also mean teaching reason".

I agree. But the proposed definition of "planet" put forward by the IUA is
based much more on sentiment than on reason. It has arbitraty and vague
boundaries designed to nearly match with tradition. The result is just
confusing and useless.

There is nothing wrong with conventions. It is also reason. We have 9
planets in the solar system, 12 months of the year, 7 days a week, 24 hours
a day.

These are all arbitrary conventions, and they work just fine. You cannot
find a scientific reason for why we should have 24 hours a day. The same
goes for number of planets. It is what we decide.

I would like to
help kids to not get mixed up in that irrational jungle they have to
grow up in. Therefore, I also talk about UFO´s

Oh dear..... I thought you said your teaching was based on reason?

If the resulution is adopted you will have to explain why Charon and
UB313 are planets,

As far as Charon is concerned I can give you the following advice:
Make
use of the term "wobble". When we have a planet and a sattelite, the
sattelite just makes the planet wobble. Since normally sattelites are
so tiny in comparison to the planet arond which they go, the wobble is
next to imperceptible. But in the case of the Earth and the Moon, the
wobble of Earth is quite strong.

And in about 10 million years or so, the Earth Moon barycenter will have
move outside the earths crust, and then, by magic, the Moon becomes a planet
according to IAU. That is quite ironic isn't it? Look, The Planet is up!

But recently we had to realize that there exist multiple planets, just
like there exist multiple stars. It really isn´t surprising at all.

You mean Earth & Moon (in 10 mill years) and Pluto & Charon.

And when we have multiple planets, then they don´t just wobble but
rotate around a point in between them.

Barycenter.

And when you have 3 objects moving in a figure 8 orbit around each other
http://www.burtleburtle.net/bob/physics/eight.html

2003UB313 (hopefully soon with a simpler and lasting name) is no
problem at all, since it is bigger than Pluto. And laypeople tend to
not have any problems with accepting Pluto as a planet.

and why Ceres has suddenly reappered on the list.

Because Hubble photographs have shown it to be a round. People have no
problems in accepting that planets are round. You seem to believe that
people are even more cognitively incapacitated than I do.

I think you
are going to find that harder with 10-year old kids. Maybe not
impossible, but much harder.

Nonsense. This is a perfect opportunity to explain to kids and elder
people why change in concepts is one of basic characteristics in
science, and why concepts assumed to be eternal tend to be false
("science is made by people").
You subestimate the potential learning capacity of homo sapiens, and
in history we have had far more drastic changes in our concept of the
solar system than what is happening right now.

Be prepared to rewind the "what is a planet?" debate in
every school.

I am not prepared to do this for the next three years.

Bring lots of copies of the IAU resolution.

This is didactic nonsense, and if you do public education you know it.


I just hope,
that it will be over soon.

I agree. In my opinion, the only way to end it is to not adopt the
proposed resolution now.

O.K. But then what?

Make a suggestion, but remember:
You may not call Pluto a planet if you do not call 2003UB313 a planet
as well (it´s either both or none). Because if you *would* do that,
then everybody *would* have the right to publicly insult you without
any restraint. If you want others to observe certain restraints, then
you also have to respect certain restraints.


Peter

Carsten A. Arnholm wrote:
wrote:
And when we have multiple planets, then they don´t just wobble but
rotate around a point in between them.

Barycenter.

And when you have 3 objects moving in a figure 8 orbit around each
other http://www.burtleburtle.net/bob/physics/eight.html

[happened to hit RETURN here, sorry]

... then the barycentre will alternate to lie inside the different bodies at
different times. The objects then switch roles between moons and planets all
the time.

and why Ceres has suddenly reappered on the list.

Because Hubble photographs have shown it to be a round.

Ceres does not reappear on the list of planets because of a scientific
discovery made by Hubble recently. It reappears only because the definition
of the word is supposed to be changing.

People haveno problems in accepting that planets are round. You seem to
believe that people are even more cognitively incapacitated than I do.

I have never claimed that people don't accept planets are round. Of course
they do, all the 9 planets are fairly round to my knowledge. But not all
round things are planets. Roundness is an arbitrary way of defining a
planet, and besides it is worthless in practice, because you will be
incapable of determining the shape of objects lying outside of say, UB313.
Such objects will be too small to be resolved by Hubble, so you have no way
of knowing whether you are looking at a planet, since you cannot determine
whether it is "sufficiently round". So the proposal fails again.

I think you
are going to find that harder with 10-year old kids. Maybe not
impossible, but much harder.

Nonsense. This is a perfect opportunity to explain to kids and elder
people why change in concepts is one of basic characteristics in
science, and why concepts assumed to be eternal tend to be false
("science is made by people").

But this is not science. It is arbitrary word games.

You subestimate the potential learning capacity of homo sapiens, and
in history we have had far more drastic changes in our concept of the
solar system than what is happening right now.

Of course, this is just a bunch of people talking about a word. It is
completely irrelevant to to science as such. It is however relevant to the
nomenclature of the solar system, so one better not come up with something
that causes more confusion. This one will.

Be prepared to rewind the "what is a planet?" debate in
every school.

I am not prepared to do this for the next three years.

Then don't suggest the IAU proposition is to be adopted. If it is, you are
going to find yourself in that discussion for much longer than 3 years. The
problem will not go away, because the definition is not useable, as you have
demonstrated.

Bring lots of copies of the IAU resolution.

This is didactic nonsense, and if you do public education you know
it.

It was meant slightly ironic. My point is that the discussion will become
complex, and you and everyone else will have to end up reading the
definition all the time, but not reach any conclusion.

I just hope,
that it will be over soon.

I agree. In my opinion, the only way to end it is to not adopt the
proposed resolution now.

O.K. But then what?

Make a suggestion, but remember:
You may not call Pluto a planet if you do not call 2003UB313 a planet
as well (it´s either both or none). Because if you *would* do that,
then everybody *would* have the right to publicly insult you without
any restraint. If you want others to observe certain restraints, then
you also have to respect certain restraints.

Excuse me, but with all due respect, now you are going crazy. If I want to
suggest a list of 9 planets, then I am giving up all my rights and people
can insult me in every way they wish, even *without any restraint* ? Excuse
me sir, but I think you took the wrong pill.

I suggest the new IAU resolution should be as follows

The planets of the solar system are by convention
1. Mercury
2. Venus
3. Earth
4. Mars
5. Jupiter
6. Saturn
7. Neptune
8. Uranus
9. Pluto.*

*) Pluto may alternatively be left out if the IAU so prefers (through
voting), and could for example be classified as a TNO (Trans Neptunian
Object)

The reason is
a) It is a closed definition. It ends the debate.
b) It is consistent with tradition and current teachings.
c) There is no arbitrary "science" in this proposal
d) It opens the possibility to define new terminology for other objects, if
needed
e) I'd like to know what the insults (see above) will be like

As to 2003UB313, lets call that a TNO and let those who decides what TNO's
are called, decide the name of 2003UB313.


--
Carsten A. Arnholm
http://arnholm.org/
N59.776 E10.457

Ed wrote:
I'm leaving just as David Levy, Jim Scotti and a host of others have
already left.
But I will leave you with a quote from an Op-Ed in yesterday's Science
Times:

"The sky is our oldest symbol of order and regularity in nature. Mess
with it at your own peril."

You mean, like
http://www.palantir.net/2001/tma1/wav/goodbye.wav

?

On Mon, 21 Aug 2006 17:57:10 -0700 (PDT), (Brian Tung)
wrote:

I also feel that the alternative
solution under consideration by the IAU is a better choice.


I don't know if this is what Greg is talking about, but there was a
recent proposal, hastily submitted by Steven Soter, that suggests
discriminating between planets on the basis of mean dynamics. There is
some physical rationale (which I haven't yet examined) for the
discriminant M/sqrt(T), where M is the mass of the body and T its period
of revolution around the Sun. When measured in Earth masses and years,
there is no known body in the range

0.0002 M/sqrt(T) 0.05

whereas there are quite a few objects in similarly-sized ranges on
either side of that gap. The range is bounded by Mars (an undoubted
planet) at the high end, and 2003 UB313 on the low end. This proposal
is certainly interesting, and unlike the original IAU proposal, it is
both precise and fairly straightforwardly suggested by the available
data. What is of some concern is whether we understand planetary
dynamics well enough to say that the gap isn't just an artifact of a
limited data set.

I don't have a link to the article handy, but it is called, strangely
enough, "What is a Planet?" and it was submitted to The Astronomical
Journal on 2006-08-16.

Brian;

I assume that you have found the article by now. But if you have not
(or for others), the link for Steven Soter's "What is a Planet?"
article is:

http://arxiv.org/ftp/astro-ph/papers/0608/0608359.pdf

An interesting note that I read elsewhere on the net:

Two planets in Gliese 876 system do come very close to each other
but they are protected by 1:2 harmonic orbit, so there is no way
they can collide with each other. That is the point of Steven Soter's
work,planets are object that made their orbits "safe" so to speak,
either by scattering smaller masses out of its orbital zone in a
Hubble time,or by influencing other planet's orbit in such way that
they orbit togetherin resonance. Anyway, planets do have "safe"
orbits.

Data on Gliese 876 system, notice how planet Gliese 876 c takes 30
daysto orbit star, while other planet in system - Gliese 876 b takes
60 daysto orbit the same star, so they are in 1:2 harmonic orbit,
and can never collide with each other:

============

1:2 harmonic orbit

Gliese 876 star.

Planet Gliese 876 c:
-------------------
http://www.extrasolar.net/planettour...l&PlanetID=156
Mass ( M sin i ): 0.56 Jupiters
Periastron Distance: 0.09 AU
Mean Distance: 0.13 AU
Apastron Distance: 0.16 AU
Orbital Period: 30.12 Days
Eccentricity: 0.27
Gravitational Influence
(Hill Sphere): 0.01 AU / 1600000 km


Planet Gliese 876 b:
-------------------
http://www.extrasolar.net/planettour...mal&PlanetID=2
Mass ( M sin i ): 1.935 ± 0.007 Jupiters
Mean Distance: 0.207 ± 0.00003 AU
Orbital Period: 60.94 ± 0.013 Days
Eccentricity: 0.0249 ± 0.0026
Gravitational Influence
(Hill Sphere): 0.025 AU / 3850000 km


Pluto is a very interesting binary KBO.

Can we call Pluto a Supermassive Asteroid? :-) (I'm just kidding
people.)

-- Kevin Heider

West Coast Swing Photos at:
http://www.pbase.com/kheider

Kevin Heider wrote:
Brian;

I assume that you have found the article by now. But if you have not
(or for others), the link for Steven Soter's "What is a Planet?"
article is:

http://arxiv.org/ftp/astro-ph/papers/0608/0608359.pdf

I had the article; what I didn't have was the URL for it, since I had
downloaded the article and then discarded the link. Thanks for finding
it.

--
Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html