[meteorite-list] Study: Earthlike planets may be common

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Sun Sep 10 13:33:00 2006
Message-ID: <20060910173254.58948.qmail_at_web36911.mail.mud.yahoo.com>

Hi all -

Boy do I feel stupid. I missed last April's Planet V
discussion. Now we can still have nine planets, one
of which, Planet V, is gone, unfortunately.

But then of course this was all bandied about on the
list in the "planet x" discussion several years ago.
I couldn't accept then that the differences seen in
meteorites could be accounted for by McSween's model
of the formation of their parent bodies. I still
can't.

Speaking about data, did you ever notice what NASA
does with data? It isn't just the way they have
thrown away imagery, the crappy crater counts, but the
way they handle meteorites as well. Sample returns
from Mars, when it appears that one could search NWA
for a fraction of the cost, and have fun on the
expeditions as well.

My thinking is that the size of the parent bodies is
indicated in the gravitational precipitation seen in
the meteorite types, and that meteorites showing
impact melts and/or meteories with two distinct
components joined by impact fusion will ultimately
lead to the validation of a good computer model of the
formation of our solar system.

My guess is that at first there was at least one
cometary impactor, then maybe another, related to the
LPBE(s?). The remains of Planet V would have had to
have landed elsewhere as well.

So the answer is "9", not "42".

good hunting,
Ed

--- "Sterling K. Webb" <sterling_k_webb_at_sbcglobal.net>
wrote:

> Hi, Darren, List.
>
> Original press release from U. Colorado:
> http://www.colorado.edu/news/releases/2006/280.html
> has more detail than the Reuters story and actually
> explains the mechanisms and how they reached the
> conclusions they did, which the Reuters story does
> not.
>
> If the Reuters story sounded a little whacky,
> read
> the above instead. These are long computer
> simulations:
> 15 runs of 8 months of number crunching, inventively
> run
> on 15 big PC's. (Cheaper than a Cray, I guess, but
> is
> 15 enough?)
>
> To start with, our solar system contained
> Mercury, Venus,
> Earth, Mars, Artemis, Jupiter, Saturn, Neptune, and
> Uranus
> (in that order!), did a little dance, planets move
> in, planets
> move out, planets get kicked out of the system; it's
> lively.
>
> The abstract of the actual scientific paper is
> at:
>
http://www.sciencemag.org/cgi/content/short/313/5792/1413
> but you can't read the full article without the
> $99/year
> subscription...
>
> Sean Raymond is also the proposer of the notion
> of the
> Mars-sized Artemis, the fifth planet, which orbited
> at the
> inner edge of the present Asteroid Zone, at 2.0 AU,
> for
> 700 million years (4.5 bya to 3.8 bya):
>
http://catdynamics.blogspot.com/2006_03_01_catdynamics_archive.html
>
> This is pretty much the same idea put forward by
> Chambers
> (only with a smaller, half-Mars planet) a few years
> ago, called
> the Planet V hypothesis:
>
http://www.space.com/scienceastronomy/solarsystem/fifth_planet_020318.html
> and
>
http://www.aas.org/publications/baas/v33n3/dps2001/505.htm
> about which we had a thread back in April.
>
> As far as the notion that most "Earth's" in the
> galaxy
> would be far wetter than our Earth, that the
> majority would
> be "waterworlds," the credit for that idea goes back
> to
> 1982 and physicist/science fiction writer David
> Brin. He
> used it as a suggestion as to why SETI searches have
> turned up no Earth-like neighbors, which I discussed
> before on the List:
>
http://six.pairlist.net/pipermail/meteorite-list/2006-February/181270.html
>
> > The terrestrial planets should have (so the
> argument goes) so
> > much more water than the Earth that they are all
> Waterworlds.
> > Intelligent life evolves, yes, but underwater, so
> the smart aliens
> > are all brainy dolphins and cephalopods, very
> philosophical,
> > but with no hands, no technology, hence no radio
> (David Brin).
>
> Of course, there has been a recent flap over a
> neurologist
> who has published an analysis that whales and
> dolphins are dumb:
> http://www.msnbc.msn.com/id/14388922/
> I can't find his original publication because Google
> is clogged
> with hundreds of outraged posts screaming that he is
> the DUMB
> organism. Saying something derogatory about dolphins
> is a sure
> way to upset people.
>
> I have previously registered dismay at
> "dynamicists" deciding
> what a planet is, yet every time one of them does a
> new computer
> simulation of the solar system, the whole origin of
> the system is
> redefined, which will inevitably cause the
> dynamicists to fracture
> into more sub-schools with every contradictory
> simulation, until
> there are as many schools of thought as there are
> thinkers...
>
> What ever happened to evidence? Is speculation
> less speculative
> if a computer does it? I happen to agree with the
> trend emerging from
> the last five years of simulation, so maybe I
> shouldn't complain. The
> trend I refer to is the idea that the present number
> and configuration
> of planets was not set in stone 4.5 billion years
> and remained
> unchanged ever after, but that the solar system has
> evolved and
> changed over the aeons, that its present state is
> just that: the way
> it is right now, just a phase, or perhaps an end
> state.
>
> The last time anyone tried to "regress" the
> solar system, that is,
> run it backwards to see what happened, it was only
> completely
> stable for about 400 to 600 million years
> "backwards." And by
> 800 million years backwards, it was a MESS,
> completely whacky
> and coming apart. This was done using a dedicated
> hardware multi-
> processor computer with more than "super-computer"
> capacity
> for this kind of calculation than a super-computer
> would have had.
>
> ["A Digital Orrery,'' James Applegate, M.
> Douglas, Y. Gursel,
> P Hunter, C. Seitz, Gerald Jay Sussman, in IEEE
> Transactions on
> Computers, C-34, No. 9, pp. 822-831, September 1985,
> reprinted
> in Lecture Notes in Physics #267 -- Use of
> supercomputers in stellar
> dynamics, Springer Verlag, 1986]
>
> So, all we know for certain is that the solar
> system has been
> configured in the present arrangement for, say, 600
> million years,
> but before that we either a) don't know, or b) it
> was different. There's
> a big gap between 3800 million years ago and 800
> million years ago;
> a lot can happen in three billion years! But while
> many can accept
> a messy solar system back in the good old days of 4
> Billion BC,
> they get very uncomfortable about a really messy
> solar system that's
> much closer in time, a kind of cosmic Not In My Back
> Yard feeling.
>
> The evidence for unsettled times in the solar
> system is there
> in the CRE ages of iron meteorites. Cosmic Ray
> Exposure (CRE)
> dates tell us how long chunks of core have floated
> around as the
> small fragments we find now. If collisions are
> uniform and random
> we would find CRE ages spread out, but instead there
> are sharp
> peaks around which CRE ages cluster, at 1000, 650,
> and 400 million
> years ago. At those dates, there were BIG episodes
> of collisions
> and breakups, flurries of big impacts. And if you're
> smashing the
> iron cores of planetesimals and large asteroids, you
> have to use
> a still BIGGER hammer to do it with.
>
> Interestingly, there are very few irons with CRE
> ages in the last
> 100 million years, so, yeah, things have been pretty
> calm lately.
>
>
>
> Sterling K. Webb
>
-------------------------------------------------------------------------------
> ----- Original Message -----
> From: "Darren Garrison" <cynapse_at_charter.net>
> To: <meteorite-list_at_meteoritecentral.com>
> Sent: Friday, September 08, 2006 10:54 AM
> Subject: [meteorite-list] Study: Earthlike planets
> may be common
>
>
>
http://www.cnn.com/2006/TECH/space/09/08/earthlike.planets.reut/index.html
>
> WASHINGTON (Reuters) -- Earthlike planets covered
> with deep oceans that
> could
> harbor life may be found in as many as a third of
> solar systems discovered
> outside of our own, U.S. researchers said on
> Thursday.
>
> These solar systems feature gas giants known as "Hot
> Jupiters," which orbit
> extremely close to their parent stars -- even closer
> than Mercury to our
> sun,
> University of Colorado researcher Sean Raymond said.
>
> The close-orbiting gassy planets may help encourage
> the formations of
> smaller,
> rocky, Earthlike planets, they reported in the
> journal Science.
>
> "We now think there is a new class of ocean-covered,
> and possibly habitable,
> planets in solar systems unlike our own," Raymond
> said in a statement.
>
> The team from Colorado, Penn State University and
> NASA's Goddard Space
> Flight
> Center Maryland ran computer simulations of various
> types of solar systems
> forming.
>
> The gas giants may help rocky planets form close to
> the suns, and may help
> pull
> in icy bodies that deliver water to the young
> planets, they found.
>
> "These gas giants cause quite a ruckus," Raymond
> said.
>
> Water is key to life as humans define it.
>
> "I think there are definitely habitable planets out
> there," Raymond said.
> "But
> any life on these planets could be very different
> from ours. There are a lot
> of
> evolutionary steps in between the formation of such
> planets in other systems
> and
> the presence of life forms looking back at us."
>
> As many as 40 percent of the 200 or so known planets
> around other stars are
> Hot
> Jupiters, the researchers said.
>
>
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Received on Sun 10 Sep 2006 01:32:54 PM PDT