Could the Earth have two cores?

Discussion in 'Earth Science' started by kaneda, Jan 8, 2009.

  1. kaneda Actual Cynic Registered Senior Member

    The idea stems from an ancient, cataclysmic collision that scientists believe occurred when a Mars-sized object hit Earth about 4.45 billion years ago. The young Earth was still so hot that it was mostly molten, and debris flung from the impact is thought to have formed the moon.

    Haluk Cetin and Fugen Ozkirim of Murray State University think the core of the Mars-sized object may have been left behind inside Earth, and that it sank down near the original inner core. There the two may still remain, either separate or as conjoined twins, locked in a tight orbit.

    Did Earth's Twin Cores Spark Plate Tectonics? : Discovery News
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  3. Burada Registered Senior Member

    Sure. Anything is possible. Start digging.
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  5. cosmictraveler Be kind to yourself always. Valued Senior Member

    Earth has many cores, apple, peach and pear to name but a few!

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  7. P. BOOM! Registered Senior Member

    How could they still orbit each other? Friction would slow them down until they merge. This probably happened very soon after impact.
  8. Ophiolite Valued Senior Member

    I would have thought that seismic data would have revealed this. The precision is pretty good, even for that far into the interior, though the liquid outer core screws things up somewhat.
  9. (Q) Encephaloid Martini Valued Senior Member

    Two cores? A solid inner and liquid outer core?
  10. gluon Banned Banned

    It would be interesting, but i bet no.
  11. Bishadi Banned Banned

    a different view but neat to expose thoughts to

    fair to at least share the idea

    good thread

    what would be turning the core? nuclear decay, reactions?

    friction don't make sense
  12. Slacker47 Paint it Black Registered Senior Member

    Pretending this does exist, they would be able to move(assuming they are both solid). The liquid outer core should be plastic enough to facilitate movement.

    However, WHY would they move? Solar gravity, orbital trajectory, grav. battle between two cores? Polarity?
  13. Red Devil Born Again Athiest Registered Senior Member

    My pc has a quad core

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  14. ichatfilipina Registered Member

    interesting topic. yes, I strongly believed Earth have 2 cores. once when you align in the depth or starting area of the gravity you will be pulled fast and landed on the land or sea
  15. Red Devil Born Again Athiest Registered Senior Member

    The earth surely would be too unstable with two cores? Whilst highly unlikely, its possible in the the Mars sized planet that hit us and formed the moon could have left its 'core' behind I suppose?
  16. Sawklwrd Banned Banned

    "The interior of the Earth is a problem at once fascinating and baffling, as one may easily judge by the vast literature and the few established facts concerning it" (Birch 1952)
  17. Ophiolite Valued Senior Member

    That quote dates from 1952. We are in 2009, almost sixty years later. The number of researchers in geophysics since 1952 is at least an order of magnitude greater than the number operating before 1952. The techniqes and technology available to them are orders of magnitude more sensitive than the best available then.
    My original statement stands: the precision is pretty good, even for that far into the interior.
  18. Sawklwrd Banned Banned

    Wegener wrote in 1915 and that was 94 years ago, even longer so I take it that means you don't believe in continental drift?

    What has that to do with anything?

    Like what? What do we now know about the core that we didn't know then?

    Consult this chart:

    High Pressure Form - Ordinary Meaning
    Certain - Dubious
    Undoubtedly - Perhaps
    Positive proof - Vague suggestion
    Unanswerable argument - Trivial objection
    Pure iron - Uncertain mixture of all the elements
  19. Ophiolite Valued Senior Member

    No I don't. I do believe in plate tectonics however. Continental drift as envisaged by Wegner does not occur. The mechanism considered by Wegner in his 1915 work is not responsible for plate tectonics. Wegner's hypothesis should not have been ignored, but that does not alter the fact that, in detail, he was wrong.
    Unless this very large number of geophysicists are just going over the same ground and reaching the same conclusions as their 1952 predecessors then they will have generated new information, new knowledge. Thus your suggestion that there are 'few established facts' about the Earth's interior would be necessarily false.
    The only way this can not be the case is if those many geophysicists have discovered absolutely nothing new about the Earth's interior. Is this your position?
    I am confident that this chart is significant and important to you. It means bugger all to me. Would you care to elucidate?

    core heat flux is 80 to 160 milliwatts per square meter (mW m‑2) into the coldest D′′ region and 35 to 70 mW m‑2 away from it. Combined with estimates from the central Pacific, this suggests a global average of 50 to 100 mW m‑2 and a total heat loss of 7.5 to 15 terawatts
    van der Hilst, R.D. et al Science, Volume 315, Issue 5820, pp. 1813- (2007).

    (i) the iron melting temperature at inner-core boundary (ICB) pressure (330 gigapascals) is 5400 (+/-400) kelvin; (ii) liquid iron at ICB conditions is about 6% denser than Earth's outer core; and (iii) the shear modulus of solid iron close to its melting line is 140 gigapascals, consistent with the seismic value for the inner core. These results reconcile melting temperature estimates based on sound velocity shock wave data with those based on diamond anvil cell experiments.
    Laio, A. et al Science, Volume 287, Issue 5455, pp. 1027-1030 (2000).

    Cosmochemical, geochemical, and geophysical studies provide evidence that Earth’s core contains iron with substantial (5 to 15%) amounts of nickel. The iron-nickel alloy Fe0.9Ni0.1 has been studied in situ by means of angle-dispersive x-ray diffraction in internally heated diamond anvil cells (DACs), and its resistance has been measured as a function of pressure and temperature. At pressures above 225 gigapascals and temperatures over 3400 kelvin, Fe0.9Ni0.1 adopts a body-centered cubic structure. Our experimental and theoretical results not only support the interpretation of shockwave data on pure iron as showing a solid-solid phase transition above about 200 gigapascals, but also suggest that iron alloys with geochemically reasonable compositions (that is, with substantial nickel, sulfur, or silicon content) adopt the bcc structure in Earth’s inner core.
    Dubrovinsky, L. et al Science, Volume 316, Issue 5833, pp. 1880- (2007).

    The travel times of seismic waves that traverse the Earth's inner core show a small but systematic variation over the past three decades. This variation is best explained by a rotation of the inner core that moves the symmetry axis of its known seismic anisotropy. The inferred rotation rate is on the order of 1° per year faster than the daily rotation of the mantle and crust.
    Song, X. & Richards, G. Nature 382, 221-224 (18 July 1996)

    Unusual physical properties at the core-mantle boundary have been inferred from seismic and geodetic observations in recent years. We show how both types of observations can be explained by a layer of silicate sediments, which accumulate at the top of the core as Earth cools. Compaction of the sediments expels most of the liquid iron but leaves behind a small amount of core material, which is entrained in mantle convection and may account for the isotopic signatures of core material in some hot spot plumes. Extraction of light elements from the liquid core also enhances the vigor of convection in the core and may increase the power available to the geodynamo. Buffett, B.A. et al Science, Volume 290, Issue 5495, pp. 1338-1342 (2000).

    Do you want more? I have several thousand.
  20. Sawklwrd Banned Banned

    You said that information from the 50s and 60s is invalid because it's now 2009. So why do you believe in plate tectonics if plate tectonics was formulated in the 50s and 60s and it's now 2009?

    It's not my suggestion. It's Harvard University professor Francis Birch's suggestion. Why do you think you know more about the Earth's interior than Harvard does?
  21. Ophiolite Valued Senior Member

    No where in my posts here, or indeed in any of the approximately 15,000 posts under this and other names, on this and other forums, do I state or imply that "information from the 50s and 60s is invalid because it's now 2009."

    Stop erecting strawmen. It is a disingenuous way to debate and makes you look like a fool.

    Science moves forward. Observations are improved in quality and quantity. Theories are adapted, or discarded. New hypotheses arise. Novel experimental methods become available. Finite element analysis on high speed computers transforms the modelling process.

    Some information from the 50's and 60's is now invalid. Other information remains relevant. I certainly wouldn't discard the work of Hess, Dietz, or Mathews and Vine, or J.Tuzo Wilson, or Le Pinchon. But much of their work turned out to be wrong. Science moves forward.

    What don't you understand. Francis Birch died in 1992. Do you seriously contend that he held the same view about the extent of our knowledge of the interior in 1992 as he did forty years earlier? Do you claim that his own contributions in the field were worthless and without any significance? (Or are you just looking for an argument?)

    Please also indicate whether you accept, based upon the examples I gave, that we have learned much more about the core since 1952. If you do not accept this please explain why you feel the cited information is incorrect.

    And, to answer your last question, I know more about the Earth's interior than those in Harvard did in 1952 precisely because of the work by Birch and many many others. The view in Harvard today would not be the view espoused by Birch in 1952. If you think otherwise I suggest you seek counselling.
  22. Sawklwrd Banned Banned

    Theories like plate tectonics and the big bang are never discarded. They are like religions for them.

    And are suppressed.

    Wegener died in 1930. 62 years before Birch.

    So anyone who has a different opinion than yours is insane?
  23. Ophiolite Valued Senior Member

    Plate tectonic theory is very unlikely to be discarded. Why? Because it has been immensely succesful at explaining a multitude of geological, geophysical, petrological and palaeontological conundrums. It will continue to be adapted as our understanding improves on the back of ever more detailed observations, but the core concept will remain in place.
    We are now measuring the motions of the plates directly and sensing the character and movement of their subducting portions. What could change is our appreciation of the mechanism that is involved in the observed process.

    We are discussing the Earth and plate tectonics. The Big Bang has no place in this discussion.
    You are starting to sound like a creationist. Please tell me you aren't one of them. I promised to give up arguing with creationists for Lent.

    You were referring to new hypotheses being suppressed. That is a surprsingly ignorant statement from someone posting on a science forum. You aren't a conspiracy theorist are you? I gave up arguing with them for Lent last year, so it's probably OK to go ahead and debate one now. Still, I'd like to know.

    What does that have to do with the price of saurkraut?

    Not at all. But anyone who believes that a scientist understanding is unlikely to improve after forty years of research has got very little grasp on reality. If that is truly what you believe, then yes, you do need counselling. I don't know if your condition would rightly be called insanity, but it certainly would indicate an unwelcome pathology. It has nothing to do with disagreeing with me. It has everything to do with failing to come to terms with reality.

    Now will you be good enough to answer the questions posed to you earlier.
    1.Do you seriously contend that Birch held the same view about the extent of our knowledge of the interior in 1992 as he did forty years earlier?
    2. Do you claim that his own contributions in the field were worthless and without any significance?
    3. Do you accept, based upon the examples I gave, that we have learned much more about the core since 1952.

    If you fail to attempt to answer these questions in a reasonable manner then I must conclude that you are trolling. I hope that is not the case.

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