Iron Snow in the core of Mercury?

3488 · May 11, 2008

I have copied this post by MeteorWayne over from 'The Port'.Fascinating stuff, it really is.<div class="postcolor">From Astronomy.com Iron 'snow' helps maintain Mercury's magnetic field Researchers are closer to understanding how planetary cores evolve. by James E. Kloeppel/University of Illinois Mariner 10 also discovered that Mercury has a weak magnetic field, about one percent as strong as Earth's. NASA [View Larger Image]May 8, 2008 New scientific evidence suggests that deep inside Mercury, iron "snow" forms and falls toward the center of the planet, much like snowflakes form in Earth's atmosphere and fall to the ground. The movement of this iron snow could be responsible for Mercury's mysterious magnetic field, say researchers from the University of Illinois and Case Western Reserve University. In a paper published in the April issue of Geophysical Research Letters, the scientists describe laboratory measurements and models that mimic conditions believed to exist within Mercury's core. "Mercury's snowing core opens up new scenarios where convection may originate and generate global magnetic fields," said University of Illinois geology professor Jie (Jackie) Li. "Our findings have direct implications for understanding the nature and evolution of Mercury's core, and those of other planets and moons." Mercury is the innermost planet in our solar system and, other than Earth, the only terrestrial planet that possesses a global magnetic field. Discovered in the 1970s by NASA's Mariner 10 spacecraft, Mercury's magnetic field is about 100 times weaker than Earth's. Made mostly of iron, Mercury's core is also thought to contain sulfur, which lowers the melting point of iron and plays an important role in producing the planet's magnetic field. http://www.astronomy.com/asy/default.aspx?c=a&id=6927</div><div class="postcolor"></div><div class="postcolor">Andrew Brown on behalf of MeteorWayne. </div> <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

3488 · May 11, 2008

Copy of my response to Wayne over @ 'The Port'.Thank you so very much Wayne. Fascinating stuff indeed. Also there is speculation based on the trajectory of MESSENGER back in January, that Mercury may have a double layered core, an Iron with some Uranium as the inner one, possibly partially molten, with a liquid Iron Sulphide outer one, that is convecting (I had seen this before been hinted at with Mariner 10, but I think back then the tracking was not as accurate as today's. MESSENGER has a better signal to noise ratio than Mariner 10). The Iron Snow makes a lot of sense also. If double layered (should be confirmed in October with the second encounter), then Mercury will be the third confirmed body to have a double layered core, along with Earth & Jupiter's moon Ganymede. The Jupiter moon Io & Venus are strongly suspected also of having dual layered cores, though not proven beyond reasonable doubt. Mercury really has been the Cinderella for far too long in terrestrial planetary research, it's great to see this situation finally being rectified with the superb MESSENGER spacecraft. <img src="http://sitelife.space.com/ver1.0/Content/images/store/6/9/26ebd809-b520-47d2-b9df-b1954d0ee5b9.Medium.gif" alt="" />  <img src="http://sitelife.space.com/ver1.0/Content/images/store/0/5/80cd8c77-3052-45bd-9575-271ef47d5186.Medium.gif" alt="" />  <img src="http://sitelife.space.com/ver1.0/Content/images/store/7/1/77192dc4-cae2-4f5d-8101-5ca506475056.Medium.gif" alt="" /> We need to keep an eye on all Mercury updates. The MESSENGER spacecraft was able to confirm that Mercury's field is driven by an active core, though on this occassion no charged particles were detected, though Mariner 10 did detect them. This is a fundemental change, though solar activity (or lack of it in January) may be responsible for the change. We'll see if there are further changes this October, September 2009 & from March 2011, by which time, the Sun should be more active. <img src="http://sitelife.space.com/ver1.0/Content/images/store/2/6/723a7b37-e688-4b0a-b66f-9979d51b3397.Medium.gif" alt="" />   Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

DrRocket · May 11, 2008

It would be interesting to see how they account for the lower gravitational forces, due both to the lower mass of Mercury and to the action taking place within the body, for the buoyancy effectds that they saw in the laboratory.  I would anticipate that in the lower g environment the induced convection would be less pronounced and hence less supportive of devlopment the a magnetic field.  Perhaps this accounts for the low magnetic field.  But a quantitative assessment considering the coupling of the various effectds would be most interesting, and I think necessary to confirm that the mechanism seen in the lab is a significant factor within the body of the planet. <div class="Discussion_UserSignature"> </div>

JonClarke · May 11, 2008

Hi AndrewWhat is the evidence for uranium in the inner core of Mercury?  How would we tell, without samples?  Jon <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

3488 · May 11, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi AndrewWhat is the evidence for uranium in the inner core of Mercury?  How would we tell, without samples?  Jon Posted by jonclarke</DIV>  Hi Jon,I would imagine it's supposition based on the fact that the core has not cooled yet, when according to some it should have by now & perhaps its presense may be felt by its mass?I am not saying myself that there is Uranium, just that it is one possibilty the decay of which, of keeping the core hot. Mercury is a real odd ball, the more we look, the weirder Mercury becomes. Perhaps I was not clear enough?Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

JonClarke · May 12, 2008

Uranium is a strongly lithophile element so would not be expected to be concentrated in the core.  The same is true of Thorium and potassium.cheers Jon <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

lildreamer · May 14, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Uranium is a strongly lithophile element so would not be expected to be concentrated in the core.  The same is true of Thorium and potassium.cheers Jon Posted by jonclarke</DIV> Hi Jonquick question - given the nature of Uranium to transmute into lead overtime - would not the core of Mercury contain more iron and lead then redioactive elements?  Plus with a close vincinty of the SUN pumping copius amounts of energy into Mercury would that not speed up the process of the transmutation -  I would think, or maybe I'm off base here....<img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-undecided.gif" border="0" alt="Undecided" title="Undecided" />(thinking) <div class="Discussion_UserSignature"> </div>

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