Did Mars cool more slowly than first thought?

[3488]

Article here.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"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".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[JonClarke]

Hi Andrew<br /><br />Good to see this story surfacing. It's an impressive paper, but very erudite.<br /><br />The implication of a very thick early atmosphere is especially interesting, as it ties in with other evidence.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>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</em>  Arthur Clarke</p> </div>

 

[billslugg]

Andrew <br />I do not understand how they can assume that the samarium parent formed in the core of a molten mars. Would not the samarium have formed in the supernova that put the metals into the solar system? <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[brellis]

This might be a breathtakingly dumb question:<br /><br />Don't volcanoes produce molten rock? Couldn't a "live" Mars have produced this kind of stuff while it was tossing up Olympus Mons? <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[JonClarke]

The argument is not that the samarium is produced in Mars but that the isotopic and elemental ratios reflect processes going on in the planetary interior. I can send the paper by email to those interested next week, if asked.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>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</em>  Arthur Clarke</p> </div>

 

[MeteorWayne]

I can't see any means for a magnetic field to increase gravity.<br /><br />What the magnetic field does is deflect the solar wind, which slows down the breakdown and removal of the atmosphere. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[h2ouniverse]

Another element pointing to hotter cores (and btw to slower cooling). This is really a trend !

 

[3488]

Hi MeteorWayne,<br /><br />That is correct, the magnetosphere, deflects the solar wind, thus preventing it from <br />eroding the martian atmosphere into space. When the magnetosphere collapsed, the<br />atmosphere was in a battle against solar wind, through replenishment from volcanoes.<br /><br />When volcanism waned, the atmosphere was doomed, to erosion.<br /><br />Also, the formation of the giant volcanoes, would have helped maintain the <br />early martian atmosphere. The big question, really, is did this continue after the martian <br />magnetosphere collapsed?<br /><br />I suspect it did, & if Mars did indeed cool more slowly, volcanism, would have continued &<br />atmospheric replenishment continued, after the collapse of the magnetosphere.<br /><br />As borman pointed out, the martian magnetosphere was powerful early on, but appeared<br />to collapse early on, when the internal dynamo ceased (does not mean the core solidified, but <br />stopped spinning quicky & / or stopped convecting).<br /><br />I too cannot see how a magnetosphere though can act as a pressure vessel????<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"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".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[3488]

Hi Joel,<br /><br />Yes its true. Element no 62 (Samarium), helping to keep the core of Mars molten!<br /><br />Only recently, Sulphur in the core of Mercury & now Samarium in the core of Mars.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"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".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[yevaud]

Differentiation <i>still</i> took place much faster than here on Earth, as witnessed by the percentage of various Pyrites at or near the Martian surface. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[jaxtraw]

Wouldn't the atmosphere have gone anyway due to the low escape velocity? The solar wind just speeds up that loss IIRC?

 

[3488]

Hi Yevaud,<br /><br />I still know that to be the case. Differentiation did occur far more quickly than with Earth.<br /><br />What the issue I think is, how much longer did it take for Mars to become relatively<br />geologically inactive?<br /><br />Certainly significant developments took place when the Tharsis volcanoes were formed.<br /><br />It would be interesting for HiRISE to image the volcanic slopes to see how erosion & <br />cratering rates are different according to altitude & various lava flows, as this may help <br />determine the rate of their build up. <br /><br />The difference in atmospheric density may hinder this approach I suppose???<br /><br />I wonder if Mars even differentiated as it formed & also I had heard suggestions that Jupiter had<br />stunted the growth of Mars, the reason behind its small size??????<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"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".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[3488]

Hi kpsting,<br /><br />Magma is underground, it is called lava when exposed on the surface. So by definition,<br />magma ocean would be underground, not necessarily at the core though. <br /><br />Most likely a magma ocean in the mantle or lower crust.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"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".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[jaxtraw]

Hmm, I thought the term "magma ocean" generally meant magma without a solid surface, i.e. when people discuss the Moon's magma ocean phase it refers to the entire surface being molten. Or maybe not. It's very late and way past my bedtime <img src="/images/icons/smile.gif" /><br /><br />Surely lava is magma which has been emitted by a volcanic process? If the entire surface is molten, you can't have lava because it has nothing to erupt through...?

 

[JonClarke]

<i>that "more slowly" isn't really slowly enough. on the timescale that it is happening we're still talking about an already cold mars more than 4bya.</i><br /><br />What do you mean by "cold" Mars certaionly had a solid crust before 4Ga. But it has had ungoing volcanism ever since.<br /><br /><i>They talk about "magma ocean" in last paragraph. do they mean a surface magma ocean or do they pertain to a molten core?</i><br /><br />Surface magma ocean<br /><br /><i>Also, they give a very specific number for how many years ago did the accretion end. IIRC, it was something like "about 4567 mya". Isn't that a bit too far in the past to know this with such accuracy? Why didn't they just say 4500 mya or something less speculative.</i><br /><br />Nd-Sm geochronometers allow such precision.<br /><br />Jon<br /> <div class="Discussion_UserSignature"> <p><em>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</em>  Arthur Clarke</p> </div>

 

[JonClarke]

Hi Andrew<br /><br />You said " Element no 62 (Samarium), helping to keep the core of Mars molten" I don't have the paprr here but I am fairly sure that that the Samarium does not keep the core molten, however its isotopes are used to determine partioning during planetary scale differentiation.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>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</em>  Arthur Clarke</p> </div>

 

[JonClarke]

<i>Differentiation still took place much faster than here on Earth, as witnessed by the percentage of various Pyrites at or near the Martian surface.</i><br /><br />What's the evidence for pyrite on the surface of Mars?<br /><br />How does this demonstrate more rapid differentiation?<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>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</em>  Arthur Clarke</p> </div>

 

[billslugg]

Samarium is a fission product of Uranium. In the proto solar cloud, the Uranium does not fission, thus the Samarium concentration is stable and its isotopic ratios change at a known rate. When the nebula condenses, the Uranium concentration is high enough that fission can occur, thus producing more Samarium. The isotopic clock is reset. I do not see how samarium production can start and stop with solidification or liquifaction though. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[JonClarke]

None of the naturally occuring Samarium isotopes are the products of uranium decay, to my knowledge. The radioactive ones have extremely long half lives (ranging from 100's of billions to 1000's of trillions of years), that is why they are negligible controbutors to a planet's heat. <br /><br />Jon <div class="Discussion_UserSignature"> <p><em>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</em>  Arthur Clarke</p> </div>

 

[yevaud]

A larger proportion of heavier elements (Pyrites in this case) is present on/near the surface compared to Earth - around 15% of total soil composition, as opposed to about 5% here. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[alokmohan]

Why Uranium does not fuse?

 

[JonClarke]

Not any more!<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>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</em>  Arthur Clarke</p> </div>

 

[dragon04]

<font color="yellow">Why Uranium does not fuse?</font><br /><br />Too massive. What element fuses in the core of the most massive star after Iron in anything approaching significant quantites?<br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[billslugg]

Uranium does not fuse anywhere. It, and all other elements heavier than iron, are produced during the .1 second or so that a supernova is at maximum compression. Elements heavier than #92 Uranium are not found in nature. Uranium and other transuranics with odd atomic weights split when they absorb a neutron. When they split they produce all manner of elements of all isotopes. <br /><br />Samarium can be made in a supernova, at a particular mixture of stable and unstable isotopes, thus starting a clock.<br /><br />It can be a product of the fission of Uranium and Thorium and others(?) This would not occur in a dispersed cloud, but only in a solid core of a planet, thus resetting the clock.<br /><br />What I do not understand is how scientists can claim that the clock gets reset each time that melting occurs. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[h2ouniverse]

Btw isn't there a similar issue with Al26?