[meteorite-list] WHAT IS A PLANET?

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Sun Jul 31 16:28:40 2005
Message-ID: <42ED344F.25BB845E_at_bhil.com>

Hi,


    Martin said a wise thing: " Formation and Society is the point."

    My point was that, from the beginning, the class Planets had two disparate
members: Terrestrials and Gas Giants. We are still arguing about how they
formed, where, when, and everything else. We were sure Gas Giants had to be far
from their stars, and now we have 100 Gas Giants smack dab up of the hot edge of
their own solar beaches, basking in the rays... We will still be arguing about
them in 2505, I have no doubt. Can we wait that long?

    So now we have a third disparate class. If you can accept two disparate
classes, why not three? Call them IceBalls or KayBo's or ColdWorlds or whatever
you like -- we got them! We can spend a millennium arguing about them, and we
will. The chief reason that we don't have a good name for them is that we know
very little about them, but we do know that they're There!

    The other thing Martin mentioned was "Society," and there's an interesting
point in that. These bodies are not close neighbors. They don't live on the same
block As We Do. We don't look up and see them with the naked eye passing by
every day, like our other familiar neighbors. We vaguely know that there are
these Strange Folk living somewhere hereabouts but not that near Our House, and
we feel that they are much Too Odd for the neighborhood. Who knows what they're
like? Don't they smell strange? Don't they eat the most horrible things? What's
that gibberish they talk?

    It's a very common human response and a very, very primitive one. It's
parochial. If you stand off at the very nearest star and look back at our solar
system, ALL the bodies that are bound to this star are huddling up to The Source
of All Energy, Our Star, whether they're achieving 300 K or 30 K, it's a lot
more energy than the 3 K of the universe generally. We belong together.
Everything inside the Comet Ball does.

    We look at the discovery image of 2003 UB313, and it's four bright pixels.
That's not a lot of information, not inspiring, not suggestive. It doesn't
engage the human imagination. By the 1800's, we could see enough of Mars to
easily picture orange deserts and dark blue-green vegetation. There were canals
and ice caps, and before you knew it, there were Martians too. They were in the
movies just this summer (again)!

     These are WORLDS, rich, complex, baffling, and chock full of amazing
things: everything is! Look at how much more fascinating the moons of Jupiter
and Saturn and Uranus and Neptune have become since we got good pictures of
them. They always were; we just couldn't see it. The orange blur that was Titan
is dispersed to reveal the most astounding fluvial geography and fascinations of
every kind, a real world, and all we got was one peek!

    A while back, during the last KBO flurry, I suggested a novel by the
physicist Robert Forward, Camelot at 30 K, a story about a full ecology and
intelligent life on a large KBO. OK, for all of its hard logic, it's too much.
It's like Voltaire's urbane Saturnians; it's an exercise, but it's the kind of
exercise we need. Brains get flabby without exercise.

    When we get that 1000 meter optical telescope on the far side of the Moon, I
mean, our Moon, the pictures of KBO's will be incredible! KBO's will be all the
rage. We will argue our heads off about what this feature and that formation
really is and how it got there. I can get a beautiful view of Uranus through my
20 centimeter telescope; it's a featureless but exquisite turquoise blob, a disk
and not a point -- that's all. Then, I look at the Voyager images...

    If we could see them better, this argument would go away. Chris suggested he
wouldn't want to call anything a planet "unless we know that it formed in the
same process that produced the other planets." I notice that you used the
definition "planet" in defining "planet" in effect? We know what you mean,
though. Again, we know of two different general modes of formation already; is
that what you mean by process?

    So, there's a third process. How does a large body form that far out where
material is (now) very scarce? They must have formed closer in, but not too
close because of the suggestion (and assumption) of low densities and more
volatiles (well retained at 30 K). We assume silicate rocks are present, but...
If they were not formed by the same general process, from the same material as
the Sun itself, then they're extra-solar, and I don't think so.

    "Planets," Terrestrial and Jovian, are still mysterious. These bodies are
just more mysterious. Our deficiency, not theirs. Say, how about a new Class:
Terrestrial and Jovian and Plutonian Planets? Naming by example is always a good
choice before you know Everything.

    "Giant Comet" (thrown at Pluto) is just a slur, based on the assumption that
these bodies are just "cast-off's" from "real" planets. Snob. From the viewpoint
of the Jovian norm, Terrestrial planets are nothing but fat asteroids, leftover
rubble, junk; they (if there were a "they") wouldn't call us planets. They'd
sneer, "Where's the hydrogen?" Besides, that formation theory is just that, an
assumption, again. The larger and larger the Plutonians we discover, the shakier
it gets.

    We don't have a good "feel" for the Plutonian Planets. (Or Jovians either,
for that matter.) H2O Ice I at 30 K is a mineral, with properties that resemble
the finest steels. I have trouble imagining metallic hydrogen or diamonds as big
as a small asteroid, but they exist just the same, without regard for the
failings of my imagination. God has a better imagination by far.

    The objection to large inclinations is based on how much extra energy it
would take to "throw away" a large body in ejection at that inclination. There's
that assumption again. Even with the limited time span we can calculate from,
the proper motions of nearby stars (a few million years, an instant), we know
that other stars have passed much more closely than one light year to our Sun,
and will again and again.

    In 534,000 years (1/8000ths of the life of the solar system), we will have a
major star less than a light year (0.78) away. On the scale of a few 10^7 years,
we plunge back and forth through the very crowded Galactic Plane. We encounter
Giant Molecular Complexes on a regular basis. GMC's, with the mass of hundreds
or thousands of stars, are the largest material objects in the Universe,
accounting for half of all the mass of "normal" matter. GMC's rule.

    These are plentiful opportunities to "stir" the inclination "pot." over four
billion years. Gravity is a weak force at 10,000,000,000 miles from the Sun and
easily tinkered with. The diffuse nature of GMC's is not relevant; gravity acts
as if from a single point, the center of mass (good old Isaac). We don't need a
"formation" explanation of high inclination. Need another nail for that coffin,
fellow?

    I got plenty of nails. What about an unbound L-class dwarf star in the
neighborhood, in a high inclination position? Such a star would be much harder
to find than a big KBO, by the way. By the "normal" distribution of L stars, the
"50/50" statistical likelihood is of one L class star within 1.1 light years of
the Sun. The plane of the galaxy is inclined at 60 degrees, so we can't look in
that plane, crowded with bright stuff. I'd search a 30 degree circle at the
galactic poles, if I was searching.

    We think of aCentauri at 4 light years as the nearest star, but within that
289 cubic light years (sphere of 4.1 lt-yr radius), there "are" or ought to be
>1 and <10 number of L class stars and if somebody finds a really dim M class
star at 1.82 light years, I'll be excited, but not surprised. Try finding
Barnard's Star with a small telescope...

    In fact, if folks start hunting Plutonian planets at high inclination sky
positions because of these discoveries, I have hopes they'll find a star instead
(I mean, in addition to some big Plutonians, of course)! I like the sound of
Terrestrial and Jovian and Plutonian planets, naming by type specimen. At the
moment, Plutonians "seem" moon-poor, so finding one, even a tiny one, at 2003
EL61 was nice. I'll bet there are more. Norse names for Plutonian satellites?


Sterling K. Webb
----------------------------------------------------------------------
Martin Altmann wrote:

> Hi Sterling&list,
>
> The naming issue seems to me almost the more interesting problem than the
> definition, from when on a lump of rock should be called "planet" (greek:
> wandering star). Does size matter? Perhaps. (at the moment a range from tiny
> Mercury and Pluto up to giant objects around other stars). Inclination? No.
> Just bad luck, if the chunk once was kicked off from the plane. Formation
> and Society is the point. Has it a family of similar members, built in the
> same region and of similar physical properties? Is there a belt?
> To decide, how to call it, is more a question of history, guess Doug will
> write us a nice homework about. At least it is easier to ask if Pluto should
> be called a planet, than to discuss each time, after a new large KBO will
> have been
> detected, whether thius then should be a planet or not.
>
> The naming. Names can be changed. In a schoolbook, I have here, I find
> orbiting the sun beyond Saturn the planets "Herschel" and "Leverier".....
>
> The dictionary of minor planets' name is to expensive for me. Maybe somone
> else could outline a little bit the development of trends in naming:
> classical mythology, groups of names from epics, names of towns, wives,
> pets, dead persons with scientific merits, living persons with scientific
> merits (the asteroid "Ssssteve", I heard, was found to be only a tiny
> satellite orbiting "Rob Haag"), dead persons with no scientific merits,
> first
> brand names...
> Cool would be a diagram, where the distribution of brightness of the minor
> planets in opposition would be plotted against those thematic name groups.
>
> If it's true, that Pluto was baptized also to give the initials of Percival
> Lowell and as it's not en vogue anymore to continue with classical greek and
> latin names, we have to find a name starting with "Mb.." to honour the
> discoverer. Guess we have to study some African myths...would be perfect
> super-PC, like Quaoar from Tongva, Sedna from the Inuit....
>
> Hey, would have been a great fun and test, how far the PC really reaches, to
> give the new object a christian name, hehe. May you imagine what an immense
> outcry this would cause in the media?
> But would be quite suitable, think to the old woodcuts and medieval drawings
> with the
> heliocentric system, where adjacent to the sphere of fixed stars are
> following the spheres of the angels according their hierarchy.
> As we we don't know, how many more KBO will be found more far away, we
> should choose a name from the lowest rank,
> thus I choose an archangel
> and to honour the discoverer, I propose the name:
>
> Michael
>
> Hummm, Sedna - Goddess of sea, Eskimo, sounds cold - Pluto, death...perhaps
> it's better to plunder the mythologies for personnel with cold, dark & icy
> attributes, to reflect the physical nature of the KBOs?
>
> In Norse mythology we have the three giants of rime.
>
> Hymir
> Daddy of the god of war Tyr. Lives at the edge of heaven.
> He has a huge cauldron, wherein he brews all the beer for the gods. Skol!
> Once he was on a fishing trip with the boss, Thor. Who was so stupid to
> catch the Midgard Snake, which entwines around the whole world.
> But Hymir cut the fishing line.
>
> Thjazi
> Had some family struggles, always hungry.
> Was slain by Odin, who pulled of Thjazi's eyes, throw them to heaven, where
> they formed a pair of stars.
> Thjazi I felled, | the giant fierce,
> And I hurled the eyes | of Alvaldi's son
> To the heavens hot above;
> Of my deeds the mightiest | marks are these,
> That all men since can see.
> What, Harbarth, didst thou the while?"
> (Who the heck is Harbath?)
>
> Gymir
> Dad of beauty queen Gerda. She symbolises also the seasons, in
> wintertime......
>
> Ooooooops, I forgot!
> Those names are not acceptable. Poor Snorri, poor Icelanders - the Sagas and
> the Edda still have a Wagner&Nazi smell
> and are allowed only as poor copies in miserable fantasy literature &
> computer role-playing games.
> Bad luck.
>
> So other suggestions?
> Buckleboo!
> Martin
>
> ----- Original Message -----
> From: "Sterling K. Webb" <kelly_at_bhil.com>
> To: "Meteorite List" <meteorite-list_at_meteoritecentral.com>
> Sent: Sunday, July 31, 2005 10:16 AM
> Subject: [meteorite-list] WHAT IS A PLANET?
>
> > Hi,
> >
> >
> > These recent discoveries of new "planets" is going to heat up the
> > on-going quarrel about what is and isn't a planet, with its increasingly
> > long definitions and conditions statements designed to trim reality in
> > the mold of the arguer's mind.
> .........
Received on Sun 31 Jul 2005 04:27:59 PM PDT