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Thread: Why has water stayed liquid on Earth?

  1. #1 Why has water stayed liquid on Earth? 
    Forum Radioactive Isotope skeptic's Avatar
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    A bit of a mystery here.

    Life began on Earth about 3.5 to 4 billion years ago. One prerequisite for this is that water has to be liquid. Yet the sun back then emitted 30% less heat than it does today. If the Earth had the current atmosphere of oxygen and nitrogen, all the water would be solid ice.

    Obviously, before photosynthetic life, there was little or no oxygen and the atmosphere was very different. It, no doubt, contained a lot more greenhouse gases. Yet current calculations based on the purported ancient atmosphere still shows that the world would have been too cold for liquid water.

    Anyone think of an answer?


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    Although the question is far from being completely answered, most theories about the origin of life on earth think it started on the ocean floor, with heat coming from hot emmissions from underneath the earth's crust. The water would have been liquid there even if the surface was frozen.


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    That is a good answer, but I believe it is incomplete. While there is evidence that there have been periods when most of the world was frozen, there is also evidence of liquid oceans way back more than 3 billion years ago. That is, rock varieties that are settled form liquid suspension.
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    If the Earth loses heat, then it must have been hotter before, eh? And if it formed from debris orbiting the young sun, then there must have been an unsettled period as well as background debris.

    I think life had statistically better chance of appearing in the relatively enormous volume of water orbiting our sun before Earth as we know it existed. A "sweet spot" relative to the sun is more likely on a disc. I imagine that as water bombarded the molten Earth (which gives us our first solid rock) life arrived with that.
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  6. #5 Re: Why has water stayed liquid on Earth? 
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    Quote Originally Posted by skeptic
    A It, no doubt, contained a lot more greenhouse gases. Yet current calculations based on the purported ancient atmosphere still shows that the world would have been too cold for liquid water.
    Would you provide the source for these current calculations please.
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    Ophiolite

    I do not have the actual calculations. My reference is an issue of New Scientist (Australian version, paper copy, 21 November, page 18)

    The item is titled "Earth's cosy blanket under a feeble sun".

    It begins :
    "Some 2.5 billion years ago, the sun was so faint the oceans should have been ice. They weren't, and this 'faint young sun paradox' has puzzled scientists for decades."

    Obviously I cannot reproduce the entire article. It talks of the paradox, and an attempt to explain it by assuming higher than previously supposed levels of nitrogen gas. The article says that calculations show even this explanation is inadequate to explain the paradox.

    In find this idea of interest, since it suggests that there is something strange and unusual about our Earth, although it will need more work to confirm if this is the case.
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    Maybe, this is better suited in the "Earth science" section. I suppose, you would get more adequate answers there.

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    Quote Originally Posted by skeptic
    It talks of the paradox, and an attempt to explain it by assuming higher than previously supposed levels of nitrogen gas.
    Are you sure it's nitrogen gas?

    Earths atmosphere 2.5Ga, consisted almost entirely of nitrogen, and altering the concentration wouldn't effect temperature.
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    Geo

    The article talked of nitrogen.
    The suggestion was not that the nitrogen itself was a greenhouse gas, but that its presence increased atmospheric density, pushing molecules closer together, and this made the difference. I admit I do not really understand. The article also suggested that the extra nitrogen has since become part of the solid part of the Earth - entering the crust and mantle by chemical combination.
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  11. #10  
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    Any particular reason Earth's great initial heat and steady cooling isn't good enough explanation for you?
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    Pong

    I don't claim to be an expert on this subject, which is why I am asking questions. The article states that the Earth should have been a giant ice block. I assume the experts behind scientific understanding of this paradox have calculated the cooling rates relevent.
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    The reality is, that climatic fluctuations did occur throughout earth's history, and one of the most important aspects of the planet's evolution is the formation of the atmosphere. Sure, the crust was hotter in the past, but steady cooling doesn't explain the Precambrian temperature fluctuations.

    The atmospheric composition has varied substantially over time, and complex interactions between the atmosphere, life, the oceans and plate tectonics alter the physical and chemical properties of the atmosphere.

    Modern plate tectonics may not have begun until the late Archaean?, as the crust was too hot for this to occur.
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    does the article state what the atmosphere contained during the period in question ? because my impression was that it would have been a bit like Venus is now, i.e. CO2, CO, N2 (with the addition of possibly more H2O than there is on Venus)

    the reason why the atmosphere is now dominated by N2 is that most of the CO2 has ended up in carbonate rocks
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    I have now found the item posted on the web.

    http://www.newscientist.com/article/...arth-warm.html

    Hope this helps.
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    unfortunately the NS blurb leaves more questions than answers

    can anyone dig up the original of the following Nature abstract ?

    it appears to have something to do with atmospheric nitrogen being subducted into the mantle as NH4+ ? can't say i have a feel whether this really would amount to a doubling of the nitrogen in the atmosphere
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    Not a giant ice block all the way through, but rather ice on the surface with liquid oceans under the ice.

    Snowball Earth may have formed four times, but has never been solid all the way down.

    http://www.snowballearth.org/
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    Quote Originally Posted by marnixR
    unfortunately the NS blurb leaves more questions than answers

    can anyone dig up the original of the following Nature abstract ?
    Ask, and ye shall receive: 8)

    http://envam1.env.uea.ac.uk/goldblattetal2009.pdf
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    cheers

    from what i gather from the article the additional nitrogen appears to be one possible building block towards explaining a higher than expected temperature 2.5Ga ago, not the one and only driving mechanism

    still, i can't help wondering - was there just more heat inside the earth at that time trying to get out, and what we really see is a weaker sun being offset by a hotter earth interior ?
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    Quote Originally Posted by marnixR
    still, i can't help wondering - was there just more heat inside the earth at that time trying to get out, and what we really see is a weaker sun being offset by a hotter earth interior ?
    This is not logical. The current heat output from the Earth in a year is about enough to melt a global layer of ice a centimetre or so thick. That's a few orders of magnitude less than solar input, even from a cool sun. You can ramp up heat production from radioactive elements, but that makes less than an order of magnitude difference. Just not enough.

    I read a paper last week where high levels of sulfur dioxide were cited as the explanation. I'll try to find a copy. I thought it was PNAS, but I can't locate it.
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  21. #20  
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    Quote Originally Posted by Ophiolite
    The current heat output from the Earth
    Currently that's a cooler mantle, through the current thickness of insulating crust. But okay "a few orders of magnitude" has me convinced.
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    The reason I find this intriguing is because of the impact on life. Life began on Earth 3 to 4 billion years ago, and evolved. The results (so far) has led to an intelligent technological species - us.

    However, it seems strange that a planet bathing in the heat and light output of a sun that has diminished its output by 30% over that same period should have always remained OK for life. If things had been even a little bit different, life, and especially its evolution into higher forms, would simply not have happened.

    Is it possible that Earth is a very special place, and a very rare situation where life can evolve? Is it possible that life elsewhere simply cannot survive and evolve for 3 billion years as it has on Earth? Due to major changes in environmental conditions that are inimical to life? Such as a sun that varies too much?

    Has the factor 'X' that changed, as for example - atmospheric composition, to permit liquid water for 3 billion years, been that very rare factor that permitted higher life forms to evolve, and is it likely to happen elsewhere in the universe?
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    apart from liquid water there's at least 2 items that set the earth apart from its neighbours, one being an oversize moon, the other being the existence of plate tectonics - i can't help feeling that plate tectonics may have been a crucial factor should life turn out to be unique to the earth within this solar system, even though i have nothing to back this hunch up
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    I can think of one or two others.
    Extra solar planets appear to have mostly highly elliptical orbits. The planets around Sol have orbits very close to circular. This means much less seasonal variation, which might be critical for life. Perhaps close to circular planetary orbits are rare?

    Lots of extra solar planetary systems seem to have very large planets in close orbit to their sun. Could such be inimical to the development of life? Our solar system, by comparison has no such large planet in close, but instead, has a large planet further out. Jupiter has been described as a 'cosmic vacuum cleaner' which sweeps up a large part of the incoming debris that might otherwise strike the Earth. Is it possible that this is also an unusual situation?

    Incidentally, the large moon around Earth seems to have a stabilising effect, stopping the Earth from developing a 'wobble' in its spin. This appears to be climatically stabilising, preventing major changes that might be inimical to life.

    Plate tectonics? I have read somewhere about how they were important to life, but I forget why. Does anyone else know?

    So the question remains. is Earth special? Are the conditions by which life can form and evolve into higher beings very rare? Does this mean that advanced life in our galaxy must also be rare?
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  25. #24  
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    The last time I pointed out an error in your posts, using vigorous Anglo-Saxon, you objected and our subsequent exchange was deleted by moderators. Do you wish me to ignore your mistakes?
    Quote Originally Posted by skeptic
    However, it seems strange that a planet bathing in the heat and light output of a sun that has diminished its output by 30% over that same period should have always remained OK for life.
    The sun's output is increasing, not decreasing, although you have the percentage about right.
    Quote Originally Posted by skeptic
    Is it possible that Earth is a very special place, and a very rare situation where life can evolve?
    See Ward and Brownlee, Rare Earth, for a readable exposition of this idea.
    Extra solar planets appear to have mostly highly elliptical orbits.
    In the solar system, with the exception of Mercury, the giant planets have greater eccentricities. We are, so far, only detecting giant planets (plus a couple of super Earths), so we might reasonably expect higher eccentricities. 36% of planets with a declared eccentricity are less than 0.082. That number is comparable with the gas and ice giants in the solar system.
    Lots of extra solar planetary systems seem to have very large planets in close orbit to their sun.
    This is partly an artifact of the detection methods. Besides, their are plenty of systems where the very large planets are a Jovian distance away.

    Quote Originally Posted by Marnix
    i can't help feeling that plate tectonics may have been a crucial factor should life turn out to be unique to the earth within this solar system, even though i have nothing to back this hunch up
    It's impossible to know where to begin.
    Without plate tectonics this would be a water world - nothing more intelligent than a catfish.
    Without plate tectonics to recycle carbon the atmospheric balance would have been screwed up long before man got involved.
    Without plate tectonics climatic zones would have remained stable and a major promoter of evolutionary change would have been eliminated.
    Without plate tectonics we would lack quartz rich sands, derived from granitic sources, to serve as UV refuges for early photosynthesisers.
    Life might have existed without plate tectonics, but it would have been immensely different, and almost certainly lacking in complexity.
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    Ophiolite

    I have absolutely no problem with a polite correction of my errors. In this case I admit the error. And thank you for pointing it out.

    I am aware of the fact that the sun's output is increasing. At the time I made that mistake my mind was thinking from present, and looking back, and from that view point (going from now back to then) the sun's output was diminishing. However, I should not have said that, so your correction is fully justified.

    However, there are times when people correcting my errors are not polite. And there are other times when I get into an argument because the correction is not correct. I reserve the option of arguing if I do not think someone is correct.
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    There's no evidence that the oceans were ever frozen. There were probably periods where most of the surface was, but below that thin layer of ice there were miles of liquid kept that way by continued cooling of earth's warm interior, radiative decay, and tidal warming from a much closer moon.
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    Quote Originally Posted by Ophiolite
    It's impossible to know where to begin.
    i was thinking specifically about the origin of life on earth, not how its later development was influenced by plate tectonics
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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    Quote Originally Posted by marnixR
    Quote Originally Posted by Ophiolite
    It's impossible to know where to begin.
    i was thinking specifically about the origin of life on earth, not how its later development was influenced by plate tectonics
    I resurrect this thread because I chanced across it while searching, then realised I had meant to reply.

    A popular view at present - though not with me - is that life may have originated in the vicinity of black smokers, which offer a wide range of temperatures and a plethora of organic molecules and inorganic substrates. Black smokers, presently at least, are a feature of mid ocean ridges, a key element of plate tectonics would therefore provide the tie in you were looking for. No plate tectonics - no black smokers - no life.
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    on the other hand, an alternative theory sees life originating around white smokers, although that is presumably also dependant on plate tectonics
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    [quote="skeptic"]Ophiolite

    It begins :
    "Some 2.5 billion years ago, the sun was so faint the oceans should have been ice. They weren't, and this 'faint young sun paradox' has puzzled scientists for decades."

    There was also alot more iron in the water back then the oceans were actually red because of all the iron that could of had an effect and if you go back even earlier the lack of impuritis in the water could of kept it from freezing (maybe I don't know much about PURE water)
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    There was a paper that came out this spring with a new approach to the paradox. I wrote a blog post in summary if anyone's interested: http://sonomae.wordpress.com/2010/04...g-sun-paradox/
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    Climatologists believe that the greenhouse gasses are responsible for keeping h2o at a liguid temperature. Other wise it'd exist as ice because there's be no barrier trapping outgoing radiation.
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    Hmmm...I can't predict that. Not so sure. But I think its apart from liquid water there's at least 2 items that set the earth apart from its neighbours, one being an oversize moon, the other being the existence of plate tectonics - i can't help feeling that plate tectonics may have been a crucial factor should life turn out to be unique to the earth within this solar system, even though i have nothing to back this hunch up.
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    Vulcanism is a result of plate tectonics, and releases CO2. Without plate tectonics, there would be no volcanoes, and all the CO2 would gradually be bound up in carbonate minerals, and be lost to the air. End result : a snowball planet.
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    I'm too lazy to read every comment, and im no expert on this subject, but when the planet formed, was the planet not molten? and therefore if water was present, it should have been a gas. not ice. as the planet cooled, the gasous form of water condensed to form the oceans.
    and wasn't the first signs of life stromatolites? large clusters of single cell organisms? 3.5Ga?

    [/quote]"Some 2.5 billion years ago, the sun was so faint the oceans should have been ice. They weren't, and this 'faint young sun paradox' has puzzled scientists for decades."

    So life would have existed b4 this ice era, 2.5Ga?
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    Quote Originally Posted by skeptic
    End result : a snowball planet.
    how could that result in a snowball planet?????
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    Quote Originally Posted by alim
    I'm too lazy to read every comment, and im no expert on this subject, but when the planet formed, was the planet not molten? and therefore if water was present, it should have been a gas. not ice. as the planet cooled, the gasous form of water condensed to form the oceans.
    and wasn't the first signs of life stromatolites? large clusters of single cell organisms? 3.5Ga?
    "Some 2.5 billion years ago, the sun was so faint the oceans should have been ice. They weren't, and this 'faint young sun paradox' has puzzled scientists for decades."

    So life would have existed b4 this ice era, 2.5Ga?
    [/quote]
    I believe life existed within a few hundred thousand years of earth forming 4.5 billion years ago. ...or so they say.
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  39. #38  
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    Quote Originally Posted by alim
    Quote Originally Posted by skeptic
    End result : a snowball planet.
    how could that result in a snowball planet?????
    Remove the CO2 and you remove the greenhouse effect, resulting in rapid cooling.
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    I understand that CO2 is a contributor to the greenhouse effect, However, Water vapour in the atmosphere accounts for 60% of the absorption of back radiation which is also part of the greenhouse effect. CO2 only accounts for 25% of the absorbtion of back radiation in the greenhouse gas process. Tropospheric Ozone accounts for 8% and the rest is Methane, CFC11, CFC 12 and Nitrous Oxide.
    So, it would seem unlikely that the absence of CO2 would stop the greenhouse affect, hence causing another Snowball effect.
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    Quote Originally Posted by alim
    I understand that CO2 is a contributor to the greenhouse effect, However, Water vapour in the atmosphere accounts for 60% of the absorption of back radiation which is also part of the greenhouse effect. CO2 only accounts for 25% of the absorbtion of back radiation in the greenhouse gas process. Tropospheric Ozone accounts for 8% and the rest is Methane, CFC11, CFC 12 and Nitrous Oxide.
    So, it would seem unlikely that the absence of CO2 would stop the greenhouse affect, hence causing another Snowball effect.
    Co2 has a half life in the atmosphere of nearly a century. H2O has a half life of about a week. Water vapor responds and provide a strong positive feedback to other forcing like Co2.
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    Lynx_Fox,

    Are you saying that in agreement with me, or just making a point?

    The global warming potential (GWP)of a gas is a function of the lifetime of the gas and radiative efficiency. In 100years, CO2 has a GWP of 1. whereas, in 100 years, CH4=25, N2O=298, CFC12=10,900.

    My point being, CO2 is not the only contributor to the greenhouse effect. I don't think it was accurate to say that because there is an absence of CO2, there is an absence of The green house effect.
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    Quote Originally Posted by alim
    Lynx_Fox,

    Are you saying that in agreement with me, or just making a point?

    The global warming potential (GWP)of a gas is a function of the lifetime of the gas and radiative efficiency. In 100years, CO2 has a GWP of 1. whereas, in 100 years, CH4=25, N2O=298, CFC12=10,900.

    My point being, CO2 is not the only contributor to the greenhouse effect. I don't think it was accurate to say that because there is an absence of CO2, there is an absence of The green house effect.
    Mostly disagreement. Without Co2 temperature would drop and you'd see a dramatic fall off of water vapor which is sensitive to even small changes in temperature. That would lead to further cooling etc. And it would happen rapidly because water is short lived in the atmosphere. If you loose the Co2 forcing, you'd rapidly, on the order of a few months also loose most of the water vapor forcing. For all intents water vapor is a dependent variable of other longer term forcing. What would remain of greenhouse forcing (from CH4, etc) would be a small fraction of what we have now.
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    I understand that this is your area of expertise, and i respect that. I am definatly not saying you are incorrect, perhaps i just don't understand;
    You're saying that if you take away CO2, temperature will decrease?
    Doesn't that make the assumption that CO2 is the only gas involved in the greenhouse effect? What about the Other gases involved in the greenhouse effect? will they not maintain the temperature?? Like i said CO2 only accounts for 25% of the absorbtion of back radiation?
    apologies if im being petulant, i would genuinely like to understand this..
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    wait wait.. i got it!
    cheers!
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    cheers



    [...forgot the smiley]
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    Quote Originally Posted by skeptic
    Fox
    Vulcanism is a result of plate tectonics, and releases CO2. Without plate tectonics, there would be no volcanoes,
    This is almost certainly incorrect. While most volcanism is associated with plate tectonics, not all volcanism is. Or, consider Mars where volcanism is expressed in several large volcanoes, but where there is only very questionable evidence for plate tectonics. Or Venus, where plate tectonics is certainly absent, but which is replete with many more forms of volcanic activity than the Earth. Or, Io. But you get my point.
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    That may all be true, but plate tectonics is what drives vulcanism on Earth. Without those actions, volcanoes would either not exist, or be rare. Thus, CO2 reduction over time.
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    You are simply incorrect. In the absence of plate tectonics on Earth volcanism would still take place. It would simply be different in character. Now you may be meaning to say that without mantle convection - a possible driving force for plate tectonics - there would be no plate tectonics, but that is really quite a different matter. Hawaii is the result of plate tectonics only inasmuch as it is so small because the Pacific plate moves over the mantle hotspot. With no plate tectonics it would attempt to rival Mons Olympus (but likely fail because of higher gravity.)
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    Sounds to me as if cause and effect here are getting tangled.

    Sure, mantle convection leads to plate tectonics, and without plate tectonics, mantle convection may cause vulcanism. Agreed.

    However, sufficient mantle convection appears to cause plate tectonics, which creates vulcanism.

    If there was no plate tectonics, it would probably mean, for an Earth size planet, a lot less vulcanism, since mantle convection that is insufficient to cause tectonics would also cause much less vulcanism.
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    You are mistaken. The volcanism would be different in character , but a thermal gradient would still exist that would lead to heat build up below the crust, that would generate partial melting. Density contrasts between melt and parent rock would lead to upward migration of magma. Result: volcanism. Look at the extensive volcanism on Venus: a planet with a much thicker crust than the Earth and no plate tectonics, yet extensive volcanism.
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    I do not think you can compare Earth and Venus in terms of mechanisms for vulcanism. That is definitely a comparison of apples and oranges. The two planets vary in so many ways.

    My information came from an article in New Scientist several years back. That does not, of course, prove it to be true, but it makes me doubt the alternatives you suggest. The author of the article emphasized the importance of plate tectonics in generating sufficient vulcanism to compensate for the tendency for CO2 to form carbonates.
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    my personal theory is that there are 2 feedback mechanisms that maintain
    atmospheric temperature and density:


    As the earth gets slightly warmer much more water vapor goes into the air
    and thunderstorms become much more common
    lifting much more warm air to the top of the troposphere
    allowing the earth to cool faster.


    As the atmosphere becomes slightly denser much more water vapor goes into the air
    and thunderstorms become much more common
    and lightening becomes much more common
    resulting in much more air being converted to reactive molecules
    which become locked up in rocks and are subducted
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  54. #53  
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    Quote Originally Posted by skeptic
    Ophiolite

    I do not think you can compare Earth and Venus in terms of mechanisms for vulcanism. That is definitely a comparison of apples and oranges. The two planets vary in so many ways.

    My information came from an article in New Scientist several years back. That does not, of course, prove it to be true, but it makes me doubt the alternatives you suggest. The author of the article emphasized the importance of plate tectonics in generating sufficient vulcanism to compensate for the tendency for CO2 to form carbonates.
    The current volcanism on the Earth contains a great deal of carbon dioxide because it recirculates the carbon trapped in carbonates then carried down by subsiding plates. I have not read the article, but suspect you have taken the wrong angle from it. The emphasis you describe is, as I have just noted, accurate: without plate tectonics most of the planets carbon dioxide would eventually get tied up in carbonates.

    But what does that have to do with volcanism. Carbon dioxide will impact details of the kind of volcanism, but it will neither promote, nor discourage it. It is simply a non-issue.

    In regard to Venus, please identify even one difference between the planets that would prohibit volcanism. They have very similar compositions, very similar structures, very similar masses. The one thing that might inhibit or delay volcanism, the crustal thickness, favours the Earth, where the crust is thinner.
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  55. #54  
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    What!!

    Where did I suggest that CO2 impacts vulcanism?
    Vulcanism releases CO2. CO2 does not cause it.
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    Perhaps the Time Lord would like to tell us when the last eruption on Venus occured and compare this with the last eruption on Earth. Then explain how the difference justifies his position.
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    sceptic,
    it is not clear just what conclusion you are deriving from the New Scientist article. I am stating clearly based on my formal education in geology and my subsequent on-going informal education in geology and planetology. I repeat, plate tectonics is not required for volcanism. More than this, extensive volcanism can occur without plate tectonics. Venus and Mars are clear examples of this. If you wish I will provide an extensive bibliography demonstrating this.

    I was not suggesting you claimed carbon dioxide impacts on volcanism. I was trying to clarify the intent of the NS article as far as you had been able to convey it. (And by the way, carbon dioxide certainly does impact on volcanism, but not in any ways relevant to this discussion.)

    John Gault,
    I suspect you were heading towards the resurfacing event thought to have occured around 600 million years ago. There has been activity more recent that that. For example: Scientific American article. from July 2009. Or evidence based on sulphur dioxide fluctuations in the atmosphere. While this item in Icarus, "Elucidating the Rate of Volcanism on Venus: Detection of Lava Eruptions Using Near-Infrared Observations" details the extenisive ongoing volcanic activity on the planet. So I really don't see what you were trying to demonstrate by your question.
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    Ophiolite

    I already agreed that vulcanism can occur without plate tectonics. Just that here on planet Earth, that is the exception. Mostly volcanoes erupt along tectonic plate junctions, or close to them.

    I do not think, though, we can compare Earth and Venus. On Venus, lead melts at ambient temperature at ground level. Finagle only knows what the temperature would be at minus 10 kms. This is simply the most obvious difference. I am sure there will be numerous other differences relevent to vulcanism.
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    i can see 2 differences that may be relevant here :

    (1) at Venus's ambient temperature many of the common carbonates can't exist (higher than their dissociation temp.)
    (2) there's precious little moisture in Venus's lower atmosphere

    both could play a role in the type of volcanism that is possible
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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    Volcanism on Venus likely arises from the same mechanism that causes large igneous provinces to develop on Earth: plume -> heating of the upper mantle -> uplift -> extension -> decompressional melting. A complicating factor is how incompatbles are segregated within Venus, if at all, and if the altered geotherm tinkers with the above mechanism in any meaningful way.
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    another stupid question ... how has water formed ?
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    Hi People
    Here's my 5 cents worth.

    The picture of things I have may be wrong, but this is it.
    There was once a time when the Moon had been made and the Earth had cooled so that a skin of solid rock had formed all about the planet.
    From far space came a big rock traveling fast, and hit us so hard that the shell of the Earth was smashed into bits.
    Time passed. Life recovered.
    Mantle currents immediately began to act on the broken pieces. As the newly formed plates moved spreading zones and subduction zones came into being.
    Prediction:
    Unless Mars has also been smashed by a big rock, we will not find terrestrial-type volcanism.
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  63. #62  
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    Hmmm, no, Mars was almost certainly volcanic at some stage;

    http://en.wikipedia.org/wiki/Olympus_Mons
    "The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair." ~ Douglas Adams
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    The Earth was probably hit by a small planet about 4.5 billion years ago, and the moon is one consequence. There is no evidence of such a smash later (apart from smaller scale hits by meteorites, and the odd asteroid).

    We do not need any such mechanism to explain tectonic activity. The mix of slow cooling, and the addition of heat inside the Earth from nuclear fission is sufficient explanation.
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    The wikipedia reference Drowsy Turtle has supplied acknowledges that there are no tectonic plates on Mars.

    I had the idea that the same second big collision might have scarred the Earthward face of the Moon.
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  66. #65  
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    Quote Originally Posted by poor mystic
    The wikipedia reference Drowsy Turtle has supplied acknowledges that there are no tectonic plates on Mars.
    Quite correct. But there were, at some stage in its past at least, active volcanoes.
    "The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair." ~ Douglas Adams
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  67. #66 Limestone/marble 
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    The original atmosphere was primarily CO2, belched out by volcano's, and was thicker then present. Early life forms consumed this CO2, turned it into exoskeletons then died, depositing their remains as limestone/marble deposits world wide. The current atmosphere was created as the waste gas from life; mostly marine algae. O2, CO2, methane and nitrogen are all byproducts of life. We see methane and nitrogen on mars. Nitrogen, like ozone, is constantly being destroyed by solar radiation and must be replenished.

    Water is only temporarily liquid. It evaporates and sublimates, condenses back into water and freezes into a solid. There have been periods in earth's distant past when large amounts of earth's water was frozen for centuries. The Greenland and Antarctic ice pack are good examples.

    It is believed that more then 1/2 of all life on earth (by weight) exists in sub-surface environments. The deepest bore holes have revealed rock consuming life. Regardless of atmospheric conditions, life will continue to do it's thing underground and in the deep ocean where temperatures remain fairly constant. This is were life on Mars likely exists; under ground.
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  68. #67  
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    'Some 2.5 billion years ago, the sun was so faint the oceans should have been ice. They weren't, and this 'faint young sun paradox' has puzzled scientists for decades."

    resurrection blues? The archives are very nteresting in here.
    coupla questions.

    If the sun grows steadily brighter, then why has the earth been steadily cooling for the past 65 million years?

    One thing I read was that the early atmosphere was oxygen starved as most of the free oxygen was attracted to iron in the ancient oceans, and settled to the bottom as iron oxide. And, only then was there enough oxygen free to enrich the atmosphere, allowing colonization of the land by plants and then animals.
    So, would an oxygen atom be more likely to join with an iron atom, or with carbon atoms?
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    Quote Originally Posted by sculptor View Post
    'Some 2.5 billion years ago, the sun was so faint the oceans should have been ice. They weren't, and this 'faint young sun paradox' has puzzled scientists for decades."

    resurrection blues? The archives are very nteresting in here.
    coupla questions.

    If the sun grows steadily brighter, then why has the earth been steadily cooling for the past 65 million years?

    One thing I read was that the early atmosphere was oxygen starved as most of the free oxygen was attracted to iron in the ancient oceans, and settled to the bottom as iron oxide. And, only then was there enough oxygen free to enrich the atmosphere, allowing colonization of the land by plants and then animals.
    So, would an oxygen atom be more likely to join with an iron atom, or with carbon atoms?
    Sculptor, I beg to differ, there are so much we cannot put dates on, it is futile to throw around date and time measurements when there is no proof of any of this.
    Some of this stuff we read does not have any truths that we can even begin to imagine. Science does not refer to spirit that would be nessary to explane some of these thing you are saying.
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  70. #69  
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    Quote Originally Posted by Mother/father View Post
    Quote Originally Posted by sculptor View Post
    'Some 2.5 billion years ago, the sun was so faint the oceans should have been ice. They weren't, and this 'faint young sun paradox' has puzzled scientists for decades."

    resurrection blues? The archives are very nteresting in here.
    coupla questions.

    If the sun grows steadily brighter, then why has the earth been steadily cooling for the past 65 million years?

    One thing I read was that the early atmosphere was oxygen starved as most of the free oxygen was attracted to iron in the ancient oceans, and settled to the bottom as iron oxide. And, only then was there enough oxygen free to enrich the atmosphere, allowing colonization of the land by plants and then animals.
    So, would an oxygen atom be more likely to join with an iron atom, or with carbon atoms?
    Sculptor, I beg to differ, there are so much we cannot put dates on, it is futile to throw around date and time measurements when there is no proof of any of this.
    Some of this stuff we read does not have any truths that we can even begin to imagine. Science does not refer to spirit that would be nessary to explane some of these thing you are saying.
    MF, I'd prefer a tad more specificity
    thanx
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  71. #70  
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    Quote Originally Posted by Mother/father View Post
    Quote Originally Posted by sculptor View Post
    'Some 2.5 billion years ago, the sun was so faint the oceans should have been ice. They weren't, and this 'faint young sun paradox' has puzzled scientists for decades."

    resurrection blues? The archives are very nteresting in here.
    coupla questions.

    If the sun grows steadily brighter, then why has the earth been steadily cooling for the past 65 million years?

    One thing I read was that the early atmosphere was oxygen starved as most of the free oxygen was attracted to iron in the ancient oceans, and settled to the bottom as iron oxide. And, only then was there enough oxygen free to enrich the atmosphere, allowing colonization of the land by plants and then animals.
    So, would an oxygen atom be more likely to join with an iron atom, or with carbon atoms?
    Sculptor, I beg to differ, there are so much we cannot put dates on, it is futile to throw around date and time measurements when there is no proof of any of this.
    Some of this stuff we read does not have any truths that we can even begin to imagine. Science does not refer to spirit that would be nessary to explane some of these thing you are saying.
    What do you mean there is no proof? Provide backing for this please.
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  72. #71  
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    I re-asked this (?) in the chemistry section:

    would an oxygen atom be more likely to join with an iron atom, or with a carbon atom?
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    Quote Originally Posted by Mother/father View Post
    Quote Originally Posted by sculptor View Post
    'Some 2.5 billion years ago, the sun was so faint the oceans should have been ice. They weren't, and this 'faint young sun paradox' has puzzled scientists for decades."

    resurrection blues? The archives are very nteresting in here.
    coupla questions.

    If the sun grows steadily brighter, then why has the earth been steadily cooling for the past 65 million years?

    One thing I read was that the early atmosphere was oxygen starved as most of the free oxygen was attracted to iron in the ancient oceans, and settled to the bottom as iron oxide. And, only then was there enough oxygen free to enrich the atmosphere, allowing colonization of the land by plants and then animals.
    So, would an oxygen atom be more likely to join with an iron atom, or with carbon atoms?
    Sculptor, I beg to differ, there are so much we cannot put dates on, it is futile to throw around date and time measurements when there is no proof of any of this.
    Some of this stuff we read does not have any truths that we can even begin to imagine. Science does not refer to spirit that would be nessary to explane some of these thing you are saying.
    Carbon is a very versatile atom it is very likely it attracted other atoms and produced astounding effects on the planet. My problem is not so much that everything changes and that at one time we could have a planet where water was frozen, it is the dates you put on these events. Carbon might have changed 20 million years ago but we are using the said atom to measure the time frame which in my estimation cannot be correct for that time period. I know of nothing that stays the same on planet earth, or in our galaxy, even change itself changes.
    If the earth is getting cooler and the sun is getting brighter ( I am taking it for granted you mean hotter) then I guess the sun is not the answer to the problem, why the earth is cooling down, maybe the sun is not getting hotter but cooler. This observation would lead me to think that the reason for the cooling down could be coming from another sourse.
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  74. #73  
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    Carbon might have changed? Elements dont work that way....
    If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. -Thorin Oakenshield

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    carbon is only versatile in that it readily engages into a multitude of bonds with various elements
    there is no indication whatsoever that the elemental properties of carbon have changed since the beginning of time
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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    Quote Originally Posted by marnixR View Post
    carbon is only versatile in that it readily engages into a multitude of bonds with various elements
    there is no indication whatsoever that the elemental properties of carbon have changed since the beginning of time
    Ok carbon might not itself change, but it does go into bonds with other elements to create change. The process we use to make the date measurements involve carbon, I am asking, can we use the same carbon to date itself? there is a part of me that will not cross this point, I cannot see how we can do that if we cannot confirm that carbon was like that in the begining.
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    Quote Originally Posted by Mother/father View Post
    Ok carbon might not itself change, but it does go into bonds with other elements to create change. The process we use to make the date measurements involve carbon, I am asking, can we use the same carbon to date itself?
    The question doesn't make too much sense. I assume you are talking about radiocarbon dating. This measures the relative ratios of different carbon isotopes in a sample. It only applies to material that was once living. It is only useful for dates a few 10s of thousands of years before the present.

    It is calibrated agaisnt other dating methods. There are very large number of different dating methods that are used for different purposes and that are cross-checked agaisnt one another to confirm that they are giving reasonably accurate results. So we have no real problem with dating minerals back millions of years.

    there is a part of me that will not cross this point, I cannot see how we can do that if we cannot confirm that carbon was like that in the begining.
    Maybe if you actually learnt about things before talking about them you might understand how they work and not just dismiss them.
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  78. #77  
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    Quote Originally Posted by Mother/father View Post
    Quote Originally Posted by marnixR View Post
    carbon is only versatile in that it readily engages into a multitude of bonds with various elements
    there is no indication whatsoever that the elemental properties of carbon have changed since the beginning of time
    Ok carbon might not itself change, but it does go into bonds with other elements to create change. The process we use to make the date measurements involve carbon, I am asking, can we use the same carbon to date itself? there is a part of me that will not cross this point, I cannot see how we can do that if we cannot confirm that carbon was like that in the begining.
    No, we do not use C14 dating for older dates. That method is only used for organic material that is less then ~50,000 years old. There are a number of other Radiometric dating techniques which use radioactive decay to measure older materials.

    Thus saying "carbon could have changed, so we shouldn't trust the age dates of the earth" is not a viable statement.
    Last edited by Paleoichneum; August 1st, 2012 at 04:21 PM.
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    i'm starting to get a feeling of deja vu - remember the radio isotope dating question thread ?
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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    Quote Originally Posted by marnixR View Post
    i'm starting to get a feeling of deja vu - remember the radio isotope dating question thread ?
    Thats the thread the prompted me to actually stop lurking and register as a member
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    Quote Originally Posted by Paleoichneum View Post
    Quote Originally Posted by Mother/father View Post
    Quote Originally Posted by marnixR View Post
    carbon is only versatile in that it readily engages into a multitude of bonds with various elements
    there is no indication whatsoever that the elemental properties of carbon have changed since the beginning of time
    Ok carbon might not itself change, but it does go into bonds with other elements to create change. The process we use to make the date measurements involve carbon, I am asking, can we use the same carbon to date itself? there is a part of me that will not cross this point, I cannot see how we can do that if we cannot confirm that carbon was like that in the begining.
    No, we do not use C14 dating for older dates. That method is only used for organic material that is less then ~50,000 years old. There are a number of other Radiometric dating techniques which use radioactive decay to measure older materials.

    Thus saying "carbon could have changed, so we shouldn't trust the age dates of the earth" is not a viable statement.
    No, we do not use C14 dating for older dates. That method is only used for organic material that is less then ~50,000 years old. There are a number of other Radiometric dating techniques which use radioactive decay to measure older materials.



    For my own understanding I can accept this version of your truths better than just willy nilly measuring with element we cannot put markers on.

    I am looking at the varification process and since I can only see these measurement on a window of time perspective, I am having a little trouble with the specific time that is given for these events.
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by Mother/father View Post
    Ok carbon might not itself change, but it does go into bonds with other elements to create change. The process we use to make the date measurements involve carbon, I am asking, can we use the same carbon to date itself?
    The question doesn't make too much sense. I assume you are talking about radiocarbon dating. This measures the relative ratios of different carbon isotopes in a sample. It only applies to material that was once living. It is only useful for dates a few 10s of thousands of years before the present.

    It is calibrated agaisnt other dating methods. There are very large number of different dating methods that are used for different purposes and that are cross-checked agaisnt one another to confirm that they are giving reasonably accurate results. So we have no real problem with dating minerals back millions of years.

    there is a part of me that will not cross this point, I cannot see how we can do that if we cannot confirm that carbon was like that in the begining.
    Maybe if you actually learnt about things before talking about them you might understand how they work and not just dismiss them.
    I think my question makes perfect sence because you are trying to answer it. I am asking question that arises in my understaning or non undrstanding of the matter.

    How should I learn about them if I do not ask questions? I am trying to bypass you extra chatter so we can stick to the thread.
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    I think it is good that you (or anyone) asks questions. I will attempt to answer when I can, as will others.

    The problem is when you make definitive statements about things that you clearly know very little about.
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    Recent research may indicate planetery albedo played a role:

    http://sonomae.wordpress.com/2010/04...g-sun-paradox/
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    Quote Originally Posted by Strange View Post
    I think it is good that you (or anyone) asks questions. I will attempt to answer when I can, as will others. ...
    OK, gee thanx
    So, if the sun is growing ever brighter, then why has the earth been steadily cooling for the last 50 million years?
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    Quote Originally Posted by sculptor View Post
    Quote Originally Posted by Strange View Post
    I think it is good that you (or anyone) asks questions. I will attempt to answer when I can, as will others. ...
    OK, gee thanx
    So, if the sun is growing ever brighter, then why has the earth been steadily cooling for the last 50 million years?
    I can't answer that one.
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by sculptor View Post
    Quote Originally Posted by Strange View Post
    I think it is good that you (or anyone) asks questions. I will attempt to answer when I can, as will others. ...
    OK, gee thanx
    So, if the sun is growing ever brighter, then why has the earth been steadily cooling for the last 50 million years?
    I can't answer that one.
    nor I
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    Quote Originally Posted by skeptic View Post
    PM

    The Earth was probably hit by a small planet about 4.5 billion years ago, and the moon is one consequence. There is no evidence of such a smash later (apart from smaller scale hits by meteorites, and the odd asteroid).

    We do not need any such mechanism to explain tectonic activity. The mix of slow cooling, and the addition of heat inside the Earth from nuclear fission is sufficient explanation.

    If I am not mistaken, the Moon orbited very closely to the Earth for a very long time after it had formed. Whereas now we get ocean tides from its orbits, it likely would have caused flexing of a more fundamental nature back when it was closer. Even now the Moon is "tidally locked" to the Earth, indicating that the flexing it experienced due to the Earth was so severe that it forced its spin to be synchronized to its orbit. The effect on Earth would have been less (since we are not tidally locked to the Moon), but probably still noticeable.

    Anyway, tidal flexing can cause volcanism. At least if it's an extreme enough case. A very severe example would be IO getting flexed by its orbit around Jupiter.


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    Quote Originally Posted by sculptor View Post
    Quote Originally Posted by Strange View Post
    I think it is good that you (or anyone) asks questions. I will attempt to answer when I can, as will others. ...
    OK, gee thanx
    So, if the sun is growing ever brighter, then why has the earth been steadily cooling for the last 50 million years?
    Do you have any scientific evicdence to support that statement?
    Realizing of coursse, that 50 million years is geologically the blink of an eye.
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    Quote Originally Posted by kojax View Post
    Quote Originally Posted by skeptic View Post
    PM

    The Earth was probably hit by a small planet about 4.5 billion years ago, and the moon is one consequence. There is no evidence of such a smash later (apart from smaller scale hits by meteorites, and the odd asteroid).

    We do not need any such mechanism to explain tectonic activity. The mix of slow cooling, and the addition of heat inside the Earth from nuclear fission is sufficient explanation.

    If I am not mistaken, the Moon orbited very closely to the Earth for a very long time after it had formed. Whereas now we get ocean tides from its orbits, it likely would have caused flexing of a more fundamental nature back when it was closer. Even now the Moon is "tidally locked" to the Earth, indicating that the flexing it experienced due to the Earth was so severe that it forced its spin to be synchronized to its orbit. The effect on Earth would have been less (since we are not tidally locked to the Moon), but probably still noticeable.

    Anyway, tidal flexing can cause volcanism. At least if it's an extreme enough case. A very severe example would be IO getting flexed by its orbit around Jupiter.


    Io (moon) - Wikipedia, the free encyclopedia
    The tidal flexing of the earth by the moon is vastly insufficient to initiate vulcanism.
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    Quote Originally Posted by Strange View Post
    I think it is good that you (or anyone) asks questions. I will attempt to answer when I can, as will others.

    The problem is when you make definitive statements about things that you clearly know very little about.
    The method I use to ask my question are based on what I know as facts and can confirm from my own understanding. I achieve very little when I take it for granted that you are right. There might be quite a lot of what you are saying that is right but I need to know if its real for me. As you should have noticed I do not make definitive statements because as far as I know nothing is definitive. I might want to agree with some portions of your observations if you your self are the observer, if not I am compelled to question your results.
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    Quote Originally Posted by Paleoichneum View Post
    Quote Originally Posted by Mother/father View Post
    Quote Originally Posted by marnixR View Post
    carbon is only versatile in that it readily engages into a multitude of bonds with various elements
    there is no indication whatsoever that the elemental properties of carbon have changed since the beginning of time
    Ok carbon might not itself change, but it does go into bonds with other elements to create change. The process we use to make the date measurements involve carbon, I am asking, can we use the same carbon to date itself? there is a part of me that will not cross this point, I cannot see how we can do that if we cannot confirm that carbon was like that in the begining.
    No, we do not use C14 dating for older dates. That method is only used for organic material that is less then ~50,000 years old. There are a number of other Radiometric dating techniques which use radioactive decay to measure older materials.

    Thus saying "carbon could have changed, so we shouldn't trust the age dates of the earth" is not a viable statement.
    I will not say I don't trust the age date of the earth, I will say it is relative in the windows of change.
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    Which is a meaningless jumble of words.
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    65_Myr_Climate_Change_Rev.jpg
    Quote Originally Posted by MeteorWayne View Post
    Do you have any scientific evicdence to support that statement?
    Realizing of coursse, that 50 million years is geologically the blink of an eye.
    &
    Geologic temperature record - Wikipedia, the free encyclopedia

    This stuff's been around for quite awhile and i don't recall it being refuted.

    So, you gonna hazard a guess answer for that question I asked?
    (or, are you just busting my chops for the hell of it?)
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    Quote Originally Posted by MeteorWayne View Post
    Which is a meaningless jumble of words.
    Change means transformation one can observe these changes from different angles.
    Although you might have swallowed the dictionary, you seem to need a lot of explanations.

    When you give answers like, Which is a meaningless jumble of words. it does not look good on you, I am sure you can do better than that. Try please explain, that shows communication skills.
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    Quote Originally Posted by Mother/father View Post
    Quote Originally Posted by Paleoichneum View Post
    Quote Originally Posted by Mother/father View Post
    Quote Originally Posted by marnixR View Post
    carbon is only versatile in that it readily engages into a multitude of bonds with various elements
    there is no indication whatsoever that the elemental properties of carbon have changed since the beginning of time
    Ok carbon might not itself change, but it does go into bonds with other elements to create change. The process we use to make the date measurements involve carbon, I am asking, can we use the same carbon to date itself? there is a part of me that will not cross this point, I cannot see how we can do that if we cannot confirm that carbon was like that in the begining.
    No, we do not use C14 dating for older dates. That method is only used for organic material that is less then ~50,000 years old. There are a number of other Radiometric dating techniques which use radioactive decay to measure older materials.

    Thus saying "carbon could have changed, so we shouldn't trust the age dates of the earth" is not a viable statement.
    No, we do not use C14 dating for older dates. That method is only used for organic material that is less then ~50,000 years old. There are a number of other Radiometric dating techniques which use radioactive decay to measure older materials.



    For my own understanding I can accept this version of your truths better than just willy nilly measuring with element we cannot put markers on.

    I am looking at the varification process and since I can only see these measurement on a window of time perspective, I am having a little trouble with the specific time that is given for these events.
    What do you mean by "put markers on"?
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    Quote Originally Posted by Mother/father View Post
    I am looking at the varification process and since I can only see these measurement on a window of time perspective, I am having a little trouble with the specific time that is given for these events.
    There are a very large number of methods of dating. Radiocarbon dating is one. There are other radiometric methods which use different elements with different half lives. This means they can be applied to different lengths (including very much longer time scales) and different types of materials (e.g. rocks). Then there is dendrochronology, which overlaps with C14 dating. There are also archaeological and historical sources. And so on...

    All of these are used to cross-check, validate and calibrate one another to come up with consistent dates.
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    I came to this thread a bit late and I'm not sure what's going on. Is the original question still in play?

    I read a study either this year or last from UCLA that said liquid water was believed to be around for 4.3 billion years (400 million years earlier than previously believed). They used the high resolution ion microprobe at UCLA to study 4 billion year old zircons which indicated the presence of water. They have a list of contacts at the facility that might be able to answer your questions more thoroughly. UCLA National Ionprobe Facility
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    This lecture by Richard Alley The Biggest Control Knob (and the 12 minutes of Q&A at the end) adds up to an hour.

    But it really is one of the best overviews of long-term paleoclimate you're likely to come across. It certainly deals with the Faint Young Sun paradox and the why liquid water question. His analogy (at about 35 mins in) explaining the link between orbital obliquity, precession and eccentricity is terrific as well as the stuff on cosmic rays and other 'interesting' phenomena.

    If you spend the time with it - and follow up some of the references he gives - you'll be well placed to deal with the next IPCC report. The lecture was 2 years after the last report and this month is the closing date for scientific papers to be considered for inclusion in the next one.

    A23A
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    Thanks! I think I've seen him on some television documentaries. Good stuff.
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    Here are a few of the dating techniques of which I am aware.
    All have their strengths and weaknesses and are prone to miscalculations via contamination, or by the individual doint the dating.
    eg: dendrocronology has fallen victim to missalligned sequences

    C14 (-50kybp)(where p=1950)(easily contaminated by natural processes and by poor collection techniques)
    Potassium Argon (50k-2 billion yrs)(dates volcanic materials)
    Fission track(20k-2billion)
    obsidion hydration(good for dating artifacts made of volcanic glass)
    paleo magnetism(for dating rocks based on magnetic orientation)
    Oxidised carbon ratios(kinda new--i don't know much about how it works or acuracy)
    racemization dating( 5k-1million years---counting ratio of left handed vs right handed amino acids)(all the rage toward the end of my days at the academy circa 40 odd years ago)

    my studies were primarily in archaeology, and i know little to nothing about dating before a billion years
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