Planetary Linguistics

Yusuf B Gursey wrote:

I happen to think the definition proposed is a good start, especially in
that it doesn't as yet resort to arbitrary continuous (as opposed to
discrete) properties. I'd suggest that something were added to the
roundness criterion, namely signoficant internal layering - which I
suppose would throw out some smaller bodies, but I don't know ebough
geology for that, other possibilities are to consider diversity of
chemical elements present - and, in the case of binary systems, to
consider only the largest as a planet (even if that would have us throw
out large bodies, after all the Moon is just a moon - as the system's
gravity centre is inside Earth - even if it is larger than other
candidate planets).

In short, to be a 'planet' (. kept, + added, - deleted),

1 . having a roughly round shape by virtue of its own gravity
2 . not being a star
3 . orbiting a star in a roughly round orbit
4 + having a core, mantle, etc, or similar geological / chemical criterion

In binary systems, instead of
5 - the gravity centre being outside any of the bodies
5 + the planet is the largest body even if the gravity centre is outside
of it, and the other(s) is/are moons

'Moon' would the be any body that meets at least 1, 2 and possibly 4,
but fails one or more of the others.

I see that this doesn't take rogue planets into account, but certainly
(3) is rewritable.

some size criterion shoudl also be included IMHO, which I think there
is.

But there you go, then you have an arbitrary limit on a continuous
value. However, (1) offers a convenient workaround for that, and I
suppose (4) might also.
--
am

laurus : rhodophyta : brezoneg : smalltalk : stargate

António Marques wrote:
Yusuf B Gursey wrote:

I happen to think the definition proposed is a good start, especially in
that it doesn't as yet resort to arbitrary continuous (as opposed to
discrete) properties. I'd suggest that something were added to the
roundness criterion, namely signoficant internal layering - which I
suppose would throw out some smaller bodies, but I don't know ebough
geology for that, other possibilities are to consider diversity of
chemical elements present - and, in the case of binary systems, to
consider only the largest as a planet (even if that would have us throw
out large bodies, after all the Moon is just a moon - as the system's
gravity centre is inside Earth - even if it is larger than other
candidate planets).

In short, to be a 'planet' (. kept, + added, - deleted),

1 . having a roughly round shape by virtue of its own gravity
2 . not being a star
3 . orbiting a star in a roughly round orbit
4 + having a core, mantle, etc, or similar geological / chemical criterion

In binary systems, instead of
5 - the gravity centre being outside any of the bodies
5 + the planet is the largest body even if the gravity centre is outside
of it, and the other(s) is/are moons

'Moon' would the be any body that meets at least 1, 2 and possibly 4,
but fails one or more of the others.

I see that this doesn't take rogue planets into account, but certainly
(3) is rewritable.

some size criterion shoudl also be included IMHO, which I think there
is.

But there you go, then you have an arbitrary limit on a continuous

I agree with you that that is a problem.

value. However, (1) offers a convenient workaround for that, and I
suppose (4) might also.
--
am

laurus : rhodophyta : brezoneg : smalltalk : stargate

John Woodgate wrote in message ...
In message , dated Fri, 18 Aug 2006, Paul J Kriha
writes

He didn't. AFAICT, Leszek was giving various meanings of the word
"pluton". The Disney dog's name is Pluto. pjk

Goofy! (;-)

The object called "2003 UB313" discovered in, let's see, hmm,
oh, yes in 2003, is bigger than Pluto. What other object deserves
more to be called Goofy? :-)

pjk

OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
2006 is YMMVI- Your mileage may vary immensely.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

wrote:

Yusuf B Gursey kirjoitti:

Yusuf B Gursey wrote:
with potentiaqlly new planets coming up, here's a list of
names of the convential nine in various languages:

http://seds.lpl.arizona.edu/nineplan...nets/days.html


note that some languages use "Pluton" for "Pluto," making
"pluton" a bad choice for the new classification.

I thought "plutino" (= a trans-Neptunian asteroid or Kuiper
belt object orbiting the Sun parallel to Pluto) was a well-
established term. Are they going to introduce "pluton" as a
new generic term for these?

Plutino has a more specific meaning, as I understand it. The term
is restricted to those KBOs that are in 3:2 orbital period ratio
to Neptune. So only a subset of KBOs are plutinos.

--
Dan Tilque

Dan Tilque wrote:
wrote:

Yusuf B Gursey kirjoitti:

Yusuf B Gursey wrote:
with potentiaqlly new planets coming up, here's a list of
names of the convential nine in various languages:

http://seds.lpl.arizona.edu/nineplan...nets/days.html


note that some languages use "Pluton" for "Pluto," making
"pluton" a bad choice for the new classification.

I thought "plutino" (= a trans-Neptunian asteroid or Kuiper
belt object orbiting the Sun parallel to Pluto) was a well-
established term. Are they going to introduce "pluton" as a
new generic term for these?

Plutino has a more specific meaning, as I understand it. The term
is restricted to those KBOs that are in 3:2 orbital period ratio
to Neptune. So only a subset of KBOs are plutinos.


then I propose that pluton be replaced by plutoid


--
Dan Tilque

Uzytkownik "António Marques" napisal w wiadomosci
...

In short, to be a 'planet' (. kept, + added, - deleted),

1 . having a roughly round shape by virtue of its own gravity
2 . not being a star
3 . orbiting a star in a roughly round orbit
4 + having a core, mantle, etc, or similar geological / chemical
criterion

But there you go, then you have an arbitrary limit on a continuous
value. However, (1) offers a convenient workaround for that, and I
suppose (4) might also.

(1) is also an arbitrary limit on a value that is continuous AND more
difficult to quantify (shape coefficient?). So is (3).

As for (4), it is hard to check before you have at least had
a very close look, if not drilled a hole in the thing - and most
planets outside of the Solar system are only detected indirectly
by watching the effects of their gravity on their mother stars
and/or passing light. And again, I am no expert, but I think
a body can be "more" or "less" stratified - another continuous
parameter that is hard to define, harder to measure,
and open to arbitrary setting of thresholds.

Perplexedly yours and lost in space,
Leszek.

In message , dated Mon, 21 Aug 2006, Leszek L.
writes
Uzytkownik "António Marques" napisal w wiadomosci
.. .

In short, to be a 'planet' (. kept, + added, - deleted),

1 . having a roughly round shape by virtue of its own gravity
2 . not being a star
3 . orbiting a star in a roughly round orbit
4 + having a core, mantle, etc, or similar geological / chemical
criterion

But there you go, then you have an arbitrary limit on a continuous
value. However, (1) offers a convenient workaround for that, and I
suppose (4) might also.

(1) is also an arbitrary limit on a value that is continuous AND more
difficult to quantify (shape coefficient?). So is (3).

As for (4), it is hard to check before you have at least had
a very close look, if not drilled a hole in the thing - and most
planets outside of the Solar system are only detected indirectly
by watching the effects of their gravity on their mother stars
and/or passing light. And again, I am no expert, but I think
a body can be "more" or "less" stratified - another continuous
parameter that is hard to define, harder to measure,
and open to arbitrary setting of thresholds.

Maybe it's easier to define a planet as 'not anything else'. Defining by
'layered structure' is not viable, because we don't know the structure
of many bodies; comets may well have layered structure, and satellites
may, too.

There IS no real distinction between a planet and an asteroid, as we see
from the re-classification of Ceres, which is just the largest of a
continuum of asteroids of sizes down to 'very small indeed'.
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
2006 is YMMVI- Your mileage may vary immensely.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Leszek L. wrote in message
...
U¿ytkownik "Edward Hennessey"
napisa³ w
wiadomo¶ci
ink.net...

Leszek L. wrote in message
...

Either capitalized or not, "pluton" in Polish
already means:

- the planet (while it still is one) Pluto;
- the element plutonium;
- an army platoon.

Making it a generic term for an "almost planet"
would make it one of the most heavily overloaded
nouns in our language.
(...)
L.L.:

And you forgot that goofy, Disney dog in English. When are
you

Forgotten HIM? You must be joking. But I was only
listing the meanings of [P|p]luton, with an 'n',
the word that is IMHO unwisely being proposed
as a term for less-than-planetary bodies.

L.L.:

I cheated with the mention;the opportunity was to good to let
go by.



going to be ready to rrrrumble?

Hard to tell. Things are getting busy around here,
and I guess I should too.

Oh yeah.

Regards,

Edward Hennessey

Leszek L. wrote:

In short, to be a 'planet' (. kept, + added, - deleted),

1 . having a roughly round shape by virtue of its own gravity
2 . not being a star
3 . orbiting a star in a roughly round orbit
4 + having a core, mantle, etc, or similar geological / chemical
criterion

But there you go, then you have an arbitrary limit on a continuous
value. However, (1) offers a convenient workaround for that, and I
suppose (4) might also.

(1) is also an arbitrary limit on a value that is continuous AND more
difficult to quantify (shape coefficient?). So is (3).

No, there's an important difference. (1) and (3) are _subjective_
(though only to a degree, of course). What happens with such criteria is
that they're ultimately decided by the general consensus (if most people
say it's round, round it is; if some say it's not and give a reasonable
defense of that position, fine). That's how the most basic stuff in
science works. Whereas, say, a diameter of 800km offers no significance
(that I know of) nor flexibility (that for sure).

As for (4), it is hard to check before you have at least had
a very close look, if not drilled a hole in the thing - and most
planets outside of the Solar system are only detected indirectly
by watching the effects of their gravity on their mother stars
and/or passing light.

And of course, if one knows not enough about the body in question to
decide, it can be postponed or assumed. When one knows better, one
reclassifies it. 'Previously though to be a planet, P4X-99111 is now
believed to lack any internal structure...'

And again, I am no expert, but I think
a body can be "more" or "less" stratified - another continuous
parameter that is hard to define, harder to measure,
and open to arbitrary setting of thresholds.

As I explain above, no thresholds are necessary. The moment you begin to
use arbitrary thresholds on a continuous scale, you compromise everything.

Then again, it doesn't really matter. If an unsatisfactory definition is
chosen today, it will simply be changed when necessary.
--
am

laurus : rhodophyta : brezoneg : smalltalk : stargate

John Woodgate wrote:

Maybe it's easier to define a planet as 'not anything else'. Defining by
'layered structure' is not viable, because we don't know the structure
of many bodies; comets may well have layered structure, and satellites
may, too.

And that is why it might be a criterion _among others_.

There IS no real distinction between a planet and an asteroid, as we see
from the re-classification of Ceres, which is just the largest of a
continuum of asteroids of sizes down to 'very small indeed'.

There is a distinction, or we wouldn't be talking about it. That it may
be hard to put into an algorithm is another matter. There are a
multitude of important concepts that can not be defined precisely, or
whose definitions must resort to other fuzzy realities. And clearly
there's an area where one's left to personal preference to tell between
two options, and I think Ceres would be a good example.

Can you give me an algorithm to, given:

- a closed perimeter ('continent')
- a set of points inside it ('cities')

divide the continent into one and one country only per city?

- the continent must not have unalloted territory
- the cities may not be run over by the borders

It's of course possible to do it with large time consuming algorithms,
or in some clever recursive way. But how do you translate the usual way
people can do the task into computational terms (given an array with the
coastline and another with the cities, produce an array of countries,
each made of line segments)? That there is no satisfactory way of doing
that won't invalidate the fact that it's the natural way for a person to
do it. Just as having trouble defining a planet doesn't mean that the
reality doesn't exist, or having trouble telling between an asteroid and
a planet ditto.
--
am

laurus : rhodophyta : brezoneg : smalltalk : stargate