[meteorite-list] 2003 EL61, IN PERSON

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Wed Sep 20 07:10:56 2006
Message-ID: <20060920111001.66373.qmail_at_web36909.mail.mud.yahoo.com>

Hi Larry, Sterlng, list -

The problem here is that all of this is not entirely
theoretical, as it is likely that some of the 64
fragments of SW3 "intend" to accrete with the Earth in
2022.

If NASA had done its work with crater counts, the
accretion problem would at least be constrained in one
way. If NASA had done its work with impactor types by
surveying Earth craters, the problem would be
constrained in another way. I always prefer it when
theory follows data, instead of the other way around.

When Ed Weiler once asked me if I expected him to find
every object in the Kuiper Belt, I told him no, I just
expected him to find the inbound ones as early as
possible. Now I'm beginning to favor the launch of
some kind of observation probe to the KB, at least to
get a handle on the size of the problem, the
distribution of the accretion disk.

What would you want launched?

good hunting,
Ed

--- Larry Lebofsky <lebofsky_at_lpl.arizona.edu> wrote:

> 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
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>
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>


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Received on Wed 20 Sep 2006 07:10:01 AM PDT