[meteorite-list] MORE STUFF ABOUT THE PLANET DEBATE

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Sun Aug 20 00:07:08 2006
Message-ID: <006501c6c3f7$c2bf1940$947f4b44_at_ATARIENGINE>

Hi, All,


    A nice piece written under the title "Is Pluto A Giant Comet?"
contains a wealth of information about the history of naming planets:
http://cfa-www.harvard.edu/cfa/ps/icq/ICQPluto.html

    It's a "Dump Pluto" piece, of course, but with lots of information
about how much the naming of planets has changed through time.

A few quotes:
    "Astronomy publications and textbooks for nearly
half a century referred to "eleven primary planets" of
the solar system [e.g., P. A. Hansen (1837), in Jahrbuch
fuer 1837, ed. by H. C. Schumacher (Stuttgart and
Tuebingen: J. G. Cotta'schen Buchhandlung), p. 83;
D. Olmsted (1847), An Introduction to Astronomy;
Designed as a Text Book for the Students of Yale College
(New York: Collins and Brother), p. 174; J. H. Wilkins (1833),
Elements of Astronomy (Boston: Hilliard, Gray, Little,
and Wilkins), p. 4], until a rush of asteroid discoveries
in the late 1840s and 1850s encouraged astronomers to
refer to them as "minor planets" or "asteroids" instead
of "primary planets". Olmsted had the four newest planets
as numbers 5, 6, 7, and 8, and Jupiter was the ninth planet.
(Note that the other seven primary planets were Mercury-Uranus,
until Neptune was discovered in 1846.) The eminent British
astronomer Sir John Herschel wrote a series of famous
textbooks on astronomy in the first half of the 19th century;
he, too, counted 11 planets, with Jupiter as the ninth, and
referred to Ceres, Juno, Pallas, and Vesta as "ultra-zodiacal
planets" in his 1833 edition of A Treatise on Astronomy."

    For a half century, we had 11+ planets, then for a half
century we had 8 planets; for the last half century we've
had 9 planets. The conservatives want to stick with nine;
the ultra-conservatives want to go back to eight. Does
anybody want to move on?

    Another good internet reference is David Jewett's site
on the Kuiper Belt Objects:
http://www.ifa.hawaii.edu/faculty/jewitt/kb.html

    From it, I discovered that Julio Fernandez of Uruguay,
the prime mover of the Alternative Definition that supports
the Eight Planet Gang, is the author and sponsor of many
theories of planetary movement (planets changing orbits),
which theories have gotten a big boost from the discovery
of extrasolar planets that apparently have "spiraled in"
toward their stars, but also a big supporter of a theory that
says Neptune spiraled out, pushing up planetary rubble as
it went, to form a narrow Kuiper Belt in front of its "gravitational
snowplow." That theory, of course, makes the objects IN
the Kuiper Belt just trash. Leftovers.
    Three guesses why he'd want to keep that Kuiper Belt
rabble out of the Planet Class.
    Jewett suggests a 1980 paper by Fernandez should be
considered the origin of the idea of the Kuiper Belt rather
than Kuiper's 1951 paper. "If anything, I would say that
J. Fernandez most nearly deserves the credit for predicting
the Kuiper Belt. His 1980 paper (Monthly Notices of the
Royal Astronomical Society, 192, 481-491) is worth a
careful read." Shall we re-name it the Fernandez Belt?

    So, Jewett is not a supporter of Proposal V, either, but his
website is very well organized, well-written, and informative,
and manages to present things in a sharp clear way, and I'm
enjoying every page of it. He does the best job of explaining
the varieties of KBO's that I've seen to date. He is also pretty
forthright about the problems with all the existing theories
about the Kuiper Belt. For example, Fernandez' theory would
predict a close, sharp outer boundary to the Kuiper Belt, but from
Jewitt we learn that the old boundary at 42 AU had to be moved,
first to 47 AU, then to 53 AU, and now to 100 AU. And it's still
moving...

    He has a section under the tab "Plan View" which shows
the KB objects as viewed from above the solar system. A good
picture is worth, well, more than a thousand words. I have no
trouble seeing where those extra-big "planets" I expect to be
found would fit in... I look at the three populations: plutinos,
main belt, and scattered disk, and the first thought that popped
into my head was "Why would you assume the scattered disk
was "scattered" from the K-Belt? It looks to me like the inner edge
of another (inclined) disk of "objects" we are just starting to
discover..." The first glimpses of an Outer Outer Solar System.
    Or maybe we should name them (when the time comes) the
Inner (Mercury to Ceres), the Middle (Jupiter to Pluto), and the
Outer System.
    The disheartening thing about eccentric distant objects is that
most of the time they would be too far away to be easily detected.
The enheartening thing about eccentric distant objects is that they
are most likely scattered by a more distant massive object. Oh, yes,
I know that the current theory is that Neptune pumped them up and
out. Piffle! Very hard to do and then only in special circumstances.
But external orbital perturbation over the long term is of a much
higher order of likelihood, impossible to avoid in fact. The mere
presence of a disk of entirely composed of eccentric bodies is
very suggestive.

    Indicating that theorists are uneasy about this is the sudden rash
of theories that this or that scattered disk object was captured
from another star. You know, if you had suggested stellar capture
as a mechanism for almost anything for the last century, you would
have been laughed out of town, but now that there an inconvenient
population of objects, suddenly it's "doesn't count; it's from
another star"?

    What comes through loud and clear is that we are gaining a lot of
new data at a great rate over the last 10 years and trying to wedge
the new data into earlier theories that were formulated on much
less data than we have now. We need a breather. It may be far too
early to have gotten it right.

    The recent Stardust mission shows that comets, assumed to have
formed out in the back end of Kuiper Kountry, are chok-full of rich
high temperature silicate goodness which has to have come from
somewhere very near the Sun. So now we have to make a major
constituent of KBO's from stuff we have to transport from very
close to the Sun out to the back end of the solar system in time
for it to be used in manufacturing comets and other icy bodies.
    Doesn't seem like a reasonable explanation to me, but then I
never thought icy bodies formed out there. The logical place to
make lots of icy bodies is at that point in the solar system, somewhere
under 5 AU where H2O vapor at near zero pressure condenses
directly into ice, at about 160-165 deg Absolute. It HAS to
condense; it's got no choice. Now, how do we transport the
tiny grains out to 40 AU to slowly accrete into KBO's? We
make comets there; Jupiter tosses'em out?

    Would that explain the brand new occultation results that show a
quadrillion 100-200 km bodies in the K-Belt? A quadrillion medium
sized bodies takes a heap of 'splaining...

    Enough for now.


Sterling K. Webb
--------------------------------------------------------------------------
Received on Sat 19 Aug 2006 09:27:11 PM PDT