[meteorite-list] Mercury data
From: Pete Pete <rsvp321_at_meteoritecentral.com>
Date: Sun, 19 Jun 2011 22:28:50 -0400 Message-ID: <BAY153-w272103DAEE25006CAFA36BF86E0_at_phx.gbl> Hi, Sterling and All, Here's an interesting little article I came across in Nature: http://www.nature.com/nature/journal/v473/n7347/full/nature10092.html http://www.nature.com/nature/journal/v473/n7347/full/nature10092.html "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? Best, Pete ---------------------------------------- > 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 > lost. > > 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: > http://www.nasa.gov/mission_pages/messenger/multimedia/mercury_images_coll_archive_1.html > > > 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 > > ______________________________________________ > > Visit the Archives at > > http://www.meteoritecentral.com/mailing-list-archives.html > > Meteorite-list mailing list > > Meteorite-list at meteoritecentral.com > > http://six.pairlist.net/mailman/listinfo/meteorite-list > > ______________________________________________ > Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > Meteorite-list at meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list Received on Sun 19 Jun 2011 10:28:50 PM PDT |
StumbleUpon del.icio.us Yahoo MyWeb |