[meteorite-list] 2003 EL61, IN PERSON

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Wed Sep 20 03:42:11 2006
Message-ID: <031c01c6dc88$40d93ec0$927cd745_at_ATARIENGINE>

Hi, Larry, EP, List,


    What Larry is talking about is what's called the
"rollover point."

    There are more big pieces than giant pieces, more
little pieces than big pieces, more tiny pieces than
little pieces, etc. It's the "Power Law."

    For those that love a little math (but not much), it's
dN/dD ~ D^(-q). In pure theory, q is 3. If you make
D (diameter) ten times bigger, then N (number) is 10^3
or 1000 times bigger. A 100-meter ball has the volume
of 1000 10-meter balls.

    If the mass is evenly distributed in every size range,
then for every 100-meter ball, there ought to 1000 10-meter
balls. But there's a hitch. When you get down to really
tiny sizes, the "numbers" become gigantic, unrealistic.

    So the "law" fails for small sizes by predicting too
damn many. It also fails for the really big sizes because,
like Larry says, they are so good at gobbling up smaller
stuff and smashing up the rest. In addition, the presence
of large objects strongly affects the orbits of little stuff,
pumping them up in eccentricity and inclination until
they're ejected. So, it fails at both ends: not so many
small pieces, fewer medium pieces, and fewer but bigger
pieces at the top end -- that's what occurs in reality.
How do we correct for it?

    Well, the "turnover point" is the size where the numbers
of little pieces go down dramatically because of the
"demolition derby" and ejection. You just don't apply
the "power law" down there. You chop the curve off.
To correct on the big end, you change the coefficient "q"
to steepen the curve, which makes fewer but bigger pieces.
There's even a formula that relates the two factors. Way
back when (for me, the 1960's), somebody whose name
I can't remember now, elegantly proved that in an accreted
disc of objects, the correct coefficient was 3.5 instead of
3.0 if you had selected the "rollover point" by his formula.
And, it seems to work most places where accretion has
run its course completely (the local neighborhood). It
doesn't work for the Asteroid Belt; it never accreted.

    The folks that theorize that the Kuiper Belt is "mass-poor"
say that for the Kuiper Belt, the correct coefficient is 4.0, or
maybe 4.5 (because that produces a depleted Kuiper Belt
with no tiny little pieces and a very limited number of big
ones, just like their theory predicts -- what a coincidence!)
They are saying that the Kuiper Belt is "over-accreted."

    The X-ray occultation result, however, can be matched
to various "power law" curves and it fits best with much
lower "q" coefficients with a lower "rollover point." This,
if true (I'm being so diplomatic here, since I obviously
think it is), suggests that the Kuiper Belt is instead actually
incompletely accreted, which is just what logic of geometry
suggests (as in my "ballroom" analogy).

    The problem is also compounded with another: should
these "extended disc" objects be considered part of the
Kuiper Belt accretion zone (completely accreted or not),
or are they a first glimpse of something totally new and
only partially discovered? As I said, the inner edge of
an Outer Outer System? Does our Sun have a "warped"
disc system?

    For thousands of years, up until 1781, the solar system
ended at Saturn. The thought of looking for more of it
never occured to anybody. When Herschel discovered
Uranus, he wasn't looking for planets. It happened entirely
because of a techological advance: the telescope. In 150
more years, the solar system stretched all the way to Pluto.
After that excitement, planet hunting became a joke again.
Why do human beings always settle back and say, "NOW,
we know it all." It's only been 14 years since we found the
first "TNO." Again, largely due to a substantial improvement
in the technology. We are just now having our eyes opened
wider, again. I don't the process is over. I think it's just
starting.

    One can be sure that if anybody finds something beyond
Neptune that's bigger than Mercury, the whole planet debate
will boil up like crazy. I have no doubt the dynamicists will
demand that the IAU dump Mercury from the Honor Roll of
Planets and assign it to Brian Marsden's care, if that happens...
The Nine, no, Eight, no, SEVEN planets of The Solar System!


Sterling K. Webb
---------------------------------------------------------------------------
----- Original Message -----
From: "Larry Lebofsky" <lebofsky_at_lpl.arizona.edu>
To: "Sterling K. Webb" <sterling_k_webb_at_sbcglobal.net>
Cc: <meteorite-list_at_meteoritecentral.com>; "E.P. Grondine"
<epgrondine_at_yahoo.com>
Sent: Tuesday, September 19, 2006 10:56 PM
Subject: Re: [meteorite-list] 2003 EL61, IN PERSON


> Sterling:
>
> And you wonder why some of us are concerned with the dynamical definitions
> for
> planets. Most of us do not understand the models and even the dynamicists
> cannot come to agreement.
>
> Oh, something to remember, when things bump into each other early on,
> things
> stick thanks to there being a lot of stuff in similar orbits. Once that is
> gone, impact velocities go up and things break up instead of accreate. If
> memory serves me (not very well these days), things should be moving
> slower
> relative to each other so easier to stick. I will have to check on that.
>
> Larry
>
> Quoting "Sterling K. Webb" <sterling_k_webb_at_sbcglobal.net>:
>
>> Hi, E.P., List,
>>
>>
>> > Yes, cometesimals - about 75 meters or so, which
>> > themselves can then accrete chaotically over time,
>>
>> Yes, but nobody thinks cometesimals contain
>> enough iron-nickel to form a differentiated body.
>> They may, but nobody believes it...
>>
>> When I expressed a doubt about accreting big
>> bodies out in the Kuiper Belt to a professional, he
>> said, "What else could it be?" Good question.
>>
>> > ...over time...
>>
>> The problem is elbow room and simple geometry.
>> How much elbow room do you have? Accretion
>> occurs because things bump into each other, because
>> the space is crowded, like a NY cocktail party.
>>
>> Clearly, the Earth accreted. If it sucked up every
>> rock from 0.80 AU out to 1.30 AU, it was drawing
>> on a "zone" with an area of about 0.80 "square AU's."
>> (The area of a circle 1.3 AU in diameter minus the
>> area of a circle 0.8 AU in diameter = "the Accretion
>> Zone.") Yes, it was a volume, because it had thickness,
>> but it was a flat disc.
>>
>> It was crowded. Rocks kept meeting rocks. It
>> happened in a hurry -- blam, Blam, BLAM, all done.
>> 10 million years? 30? 50? Opinions vary, but quick,
>> all agree.
>>
>> Out in the Kuiper Belt, very narrowly defined as
>> from 38 AU out to 48 AU, there's 1583 "square AU's"!
>> That's almost 2000 times more room! Your odds of
>> bumping into something are 2000 times smaller.
>>
>> Imagine you're in a ballroom with 3999 other
>> people, all 4000 of you milling around in constant
>> motion and blindfolded so you can't look where
>> you're going: bump, Bump, BUMP.
>>
>> Now, imagine that you're in the SAME ballroom
>> with one other person (just the two of you). What
>> are the chances of you two (blindfolded and with
>> ear plugs) colliding?
>>
>> Well, since your odds of meeting up are 2000
>> times smaller, it's going to take 2000 times as long
>> for it to happen. Hey, no problemo! If the Earth
>> accretes in a snappy 10 million years, then objects
>> in the Kuiper Belt will accrete in only... scribble,
>> scribble... 20 Billion Years!
>>
>> No, wait! Does that sound wrong to you?
>> You see the problem...
>>
>> Well, the theoretical dynamicists must have
>> an answer, something we haven't thought of,
>> right? They do indeed have solutions. What
>> are they?
>>
>> Simple, just put 100 times more mass in the
>> Kuiper Belt (or 200 times more or 500 times more)
>> and it speeds things up to where bodies can accrete
>> there in ONLY a billion years or less! Or more...
>>
>> Wow, the Kuiper Belt must be MASSIVE!
>> Oh, no, they reply, the whole thing has less than
>> 0.10 Earth masses for all objects big and small.
>> All that mass is gone...
>>
>> I smell a problem. It took the inner solar system,
>> where things accrete in a flash, 600 million years to
>> clean up the leftovers (the Late Bombardment, you
>> remember; it was a big hit). The same process in the
>> Kuiper Belt? With 100 times the mass, it will take
>> 20 times as long (6 billion years). The leftovers
>> should still be there. If not, where'd the mass go?
>>
>> There are lots of "mass-wasting" theories. I didn't
>> invent that silly term; that's what they're called.
>>
>> Not to go on too long, the answer is: it got swept
>> under the rug. There are numerous complicated and
>> unlikely scenarios. Julio Fernandez and school push
>> a theory in which Neptune, pumped up by a resonance
>> with Saturn, spirals outward (while the other giants
>> spiral inward), with Neptune pushing the KB in front
>> of it, compressing it and making fast accretion happen,
>> until Neptune finally stops with the KB on its doorstep,
>> where Neptune can then spend billions of years
>> perturbing the rest of the mass away, and leaving
>> little total mass for the Kuiper Belt.
>>
>> Of course, they could just be WRONG about the
>> mass-poor Kuiper Belt. Look a sharp, economical test
>> of Kuiper Belt theory described in:
>> http://www.nature.com/nature/journal/v442/n7103/full/442640a.html
>> The data had already been collected by NASA.
>> (The full article is at:
>> http://www.nature.com/nature/journal/v442/n7103/full/nature04941.html)
>> They found perhaps 1000 times more mass than
>> theory allows. So maybe the mass is still there?
>>
>> One prediction of theory is that the Kuiper Belt has
>> a sharply cut-off outer edge, and that past that edge,
>> there are no more TNO's all the way out to the Oort
>> Cloud, a great deserted and empty zone, with a sign
>> at 42 AU or 48 AU that says: "Now leaving the Solar
>> System. No Gas Stations for 20,000 AU." In other
>> words, there's nothing out there TO find.
>>
>> This, of course, is where all the bolts come loose
>> and the wheels fall off! This is exactly where we are
>> finding things. First called the "Scattered Disc" (on
>> the assumption that Neptune tossed'em out there) and
>> then the "Extended Scattered Disk," or the "Distant
>> Detached Disc," we now have a slew of large interesting
>> objects that Neptune could never have had anything to
>> do with.
>>
>> Finding Sedna was kind of a last straw. Brown, who
>> discovered it says, "Sedna shouldn't be there. There's
>> no way to put Sedna where it is. It never comes close
>> enough to be affected by the sun, but it never goes far
>> enough away from the sun to be affected by other stars...
>> Sedna is stuck, frozen in place; there's no way to move it,
>> basically there's no way to put it there - unless it formed
>> there. But it's in a very elliptical orbit like that. It simply
>> can't be there. There's no possible way - except it is.
>> So how, then?"
>>
>> Sedna has been "explained" as an Oort Cloud object,
>> which tacitly moves the inner Oort Cloud boundary in
>> from 20,000 AU to under 1000 AU and creates an "Oort
>> Disc" in the bargain! Those Oortians are sneaky... They
>> creep right up on you.
>>
>> Then some theoreticians have claimed that Sedna
>> is the captured planet of another star. Kenyon at Harvard
>> CfA: "If we find planets with orbital inclinations of more
>> than 40?, it is almost certain that these are extrasolar
>> planets formed in another solar system." Then, along
>> comes ERIS, the former 2003 UB313, which meets that
>> qualification. Extra-solar planet?
>>
>> > ...it would be real nice to get some
>> > good spectra of 2003 EL61 right now...
>>
>> Oh, for one lousy gritty gram of sample return, as
>> there are only about 80 isotope assays any one of which
>> could decide between material formed with Our Star or
>> formed with Some Other Star!
>>
>> All these high inclination objects have also provided
>> a big boost to the "Sun's Companion Star" theories
>> we all remember so well, like Nemesis. It still has its
>> backers, and they're all elated. Of course, what they
>> don't tell you is that you don't need a brown dwarf
>> star to perturb disc objects in inclination; all you
>> need is an Earth mass object at 1200 AU. The Outer
>> Outer System is waiting to be discovered... I think.
>>
>> Then, there's 2005 XR190, code name "Buffy." If
>> Sedna is impossible, then "Buffy" is impossibility cubed!
>> The size of Ceres, it's in a nice normal almost CIRCULAR
>> orbit inclined at 45 degrees to the solar system at 52 to
>> 62 AU's out, dynamically independent of any influence
>> from ANY solar system objects and is equally impossible
>> as a star capture. "Buffy" is "The Theory Slayer"! Poof!
>> Your life's work is dust...
>>
>> That we are finding ANY high-inclination objects is
>> a miracle. Astronomers are STILL just looking at the
>> Ecliptic and nowhere else. A high-inclination object is
>> near or in the Ecliptic plane for just 2% of its orbital
>> travel, so for every one you find there, there are 49
>> others you're MISSING, by not looking where they
>> are!
>>
>> Duh!
>>
>> One of the best times ever is when Reality just flat
>> outruns Theory and leaves it panting in the dust, don't
>> you think? I certainly do.
>>
>> Of course, another effect of this situation is that
>> the Theory Machines all get their throttles cranked up
>> to "Hyper Overdrive" and a lot of Theory Juice gets
>> splattered all over the place. What we actually need
>> is to let the Theory Machines cool down and collect
>> more Reality
>>
>>
>> Sterling K. Webb
>> ----------------------------------------------------------
>> ----- Original Message -----
>> From: "E.P. Grondine" <epgrondine_at_yahoo.com>
>> To: <meteorite-list_at_meteoritecentral.com>
>> Sent: Tuesday, September 19, 2006 9:23 AM
>> Subject: Re: [meteorite-list] 2003 EL61, IN PERSON
>>
>>
>> > Hi Sterling, list -
>> >
>> > "but core-forming planetesimals all the way out in
>> > Kuiper Belt?!"
>> >
>> > Yes, cometissimals - about 75 meters or so, which
>> > themselves can then accrete chaotically over time,
>> > with the heavy elements always gravitationally
>> > precipitating towards the center - the lighter
>> > volatiles always on the outside - and you have
>> > delivery to the surfaces of larger bodies -
>> >
>> > Given the problems this presents us for dealing with
>> > cometary impactors, it would be real nice to get some
>> > good spectra of 2003 EL61 right now, but as always,
>> > this kind of study recieves a low priority from the
>> > failed nuclear physicists who control the telescopes
>> > and observing budgets -
>> >
>> > by the way, the 64 fragments of SW3 should be in the
>> > Earth's vicinity in 2022, though I don't have any dead
>> > on forecasts yet - as a matter of fact, I wonder where
>> > they are, and how this is being handled, so if anyone
>> > hears anything, please pass it on -
>> >
>> > good hunting,
>> > Ed
>> >
>> >
>> >
>>
>>
>
>
> --
> Dr. Larry A. Lebofsky
> Senior Research Scientist
> Co-editor, Meteorite "If you give a man a fish,
> Lunar and Planetary Laboratory you feed him for a day.
> 1541 East University If you teach a man to fish,
> University of Arizona you feed him for a lifetime."
> Tucson, AZ 85721-0063 ~Chinese Proverb
> Phone: 520-621-6947
> FAX: 520-621-8364
> e-mail: lebofsky_at_lpl.arizona.edu
>
Received on Wed 20 Sep 2006 03:41:58 AM PDT