[meteorite-list] Mercury data
From: Pete Pete <rsvp321_at_meteoritecentral.com>
Date: Sun, 19 Jun 2011 22:28:50 -0400
Hi, Sterling and All,
Here's an interesting little article I came across in Nature:
"Unbound or distant planetary mass population detected by gravitational microlensing"
I know they've suspected wandering stars in the past, but now planets!
If there's these big ones, what's to say there aren't smaller ones?
> From: sterling_k_webb at sbcglobal.net
> To: agee at unm.edu; meteorite-list at meteoritecentral.com
> Date: Sun, 19 Jun 2011 17:59:52 -0500
> Subject: Re: [meteorite-list] Mercury data
> Thanks, Carl. That's was what I was hoping for.
> There are two "Theories of Mercury" --- the old one,
> that Mercury formed from inner disk materials, all
> iron and refractories, and the new one, that Mercury
> suffered a "Giant Impact' which added its iron to the
> Mercurian core but blasted Mercury's crust off to be
> Sometimes the Giant Impact Theory is interpreted
> as a much-larger Mercury that lost much of its crust
> to a series of Pretty Dam Big Impacts that contributed
> no iron but blasted Mercury's crust off to be lost just
> the same.
> The old "All Iron And Refractories" theory seems, at
> first glance, to be dead, but wait! there's still a heart
> beat. The Crust is not The Planet. If Mercury has been
> pasted through the ages by errant asteroids and comets
> from Out-System that have been tossed down into high
> eccentricity orbits, that crust of volatiles could be the
> accretion of 4 billion years of Jupiter's trash toss-out.
> There's a lot wrong with this idea. It's hard to deliver
> material to Mercury without splashing it right off into
> the grip of the Sun's powerful gravity, and it would
> take a lot of material to pave a planet miles deep.
> Perhaps the "anomalous" crust was delivered by the
> Late Bombardment?
> Sulfur, visible as yellow swirls, streaks and patches
> surrounding the pits that burped it, got up and
> screamed "Volatiles!" even before those scans were
> released. It's just like Io, but a lot hotter. It can't
> accumulate like it does on Io Still, if Mercury is
> still boiling out sulfur after "billions and billions"
> of years, it must have started with a LOT of volatiles.
> Recent images of Mercury can be found at:
> > Maybe Mercury formed farther from the
> > Sun and migrated inwards...
> It's a whole new solar system. Jumpin' Jupiter
> wandering back and forth . Now, we have Migrating
> Mercury. The problem is "migrated from where?"
> Where do huge-iron-cored terrestrial planets with
> scads of volatiles form? It's really hard to think of
> any spot that provides vast amounts of both.
> Sterling K. Webb
> ----- Original Message -----
> From: "Carl Agee" <agee at unm.edu>
> To: <meteorite-list at meteoritecentral.com>
> Sent: Sunday, June 19, 2011 11:16 AM
> Subject: [meteorite-list] Mercury data
> > Of course it's still early days on understanding the Mercury data
> > coming back from Messenger, but I think there are a few simple things
> > that can be said about the two geochemical graphs that were part of
> > the press release. The major element graph of Al/Si versus Mg/Si
> > clearly shows that the measured Mercurian surface is similar to
> > basaltic and mantle rocks from the Earth. They plot along the Earth
> > array and look to be a bit more olivine-rich than mid-ocean ridge
> > basalts, but not as olivinerich as mantle peridotites, perhaps more
> > like Archean Earth komatiites. The measured Mercurian surface is NOT
> > delpleted in aluminum, like Martian basalts or Angrites. Also,
> > Messenger is clearly not measuring rocks like the lunar anorthositic
> > highlands. The major element that is still missing from this puzzle is
> > iron. The data do not say anything about the FeO content of the
> > Mercurian surface -- this is a pretty big deal, and until that is
> > known it will difficult to know exactly what we are looking at -- let
> > alone if there is a match for any known meteorite type.
> > The potassium/thorium plot shows that Mercury is a lot like the other
> > terrestrial planets in terms of volatile element content. It seems to
> > be closest to the K/Th of Mars which is quite surprising, since Mars
> > is thought to be the most volatile rich of the rocky planets. This
> > runs counter to the idea that the inner solar system is chemically
> > zoned with volatile elements concentrated out at Mars and lower in
> > towards the Sun. But who knows? Maybe Mercury formed farther from the
> > Sun and migrated inwards.
> > There was a brief mention of substantial amounts of sulfur, but no
> > data in the multimedia press release, so it would be interesting to
> > know what they mean by "substantial amounts". Also, why do they think
> > it is in the form of sulfide and not sulfate?
> > See how important these missions of planetary exploration are and how
> > fragmentary our understanding is?
> > Just my opinion....
> > Carl Agee
> > --
> > Carl B. Agee
> > Director and Curator, Institute of Meteoritics
> > Professor, Earth and Planetary Sciences
> > MSC03 2050
> > University of New Mexico
> > Albuquerque NM 87131-1126
> > Tel: (505) 750-7172
> > Fax: (505) 277-3577
> > Email: agee at unm.edu
> > http://epswww.unm.edu/iom/pers/agee.html
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Received on Sun 19 Jun 2011 10:28:50 PM PDT