Page 1 of 2 12 LastLast
Results 1 to 30 of 46

Thread: Did Earth coalesce from 2 medium sized planets?

  1. #1
    Join Date
    May 2010
    Posts
    29

    Did Earth coalesce from 2 medium sized planets?

    When Worlds Collided.

    Heaven and PreEarth were planets, a binary system orbiting the Sun. This happy arrangement continued for countless years, until, some unfortunate circumstance caused Heaven to collide with PreEarth, forming the Earth.

    We investigate the evidence that the Earth is the child of such a collision. We show that the planets Heaven and PreEarth were of similar size and mass. We show that many of the Earth's topographical features, such as mountain chains and ocean basins, were created during the collision. We show that certain hard to explain features of the Earth, such as its magnetic field, can now be more easily understood. And, in establishing all this, we uncover a new theory on the origin of the Moon.

    Much of PreEarth's crust survived the impact and is today the continental crust of the Earth. Although broken and contorted, giant pieces of the ancient crust acted as ships floating on a newly molten interior, insulating, and protecting, life from the fires below. Heaven itself, together with its crust, if it had one, disappeared into the interior of the PreEarth, never to be seen again. If we put the broken pieces of PreEarth's crust back together, we obtain the following map.



    This map is a flat representation of part of a globe. Hence, some distortion is inevitable.....

    Read the rest here: http://preearth.net/

    The whole idea of the theory is summarized by this animatation:

    http://preearth.net/impact-view.gif

    The impact area was that within the circle.

    Pangaea (considered as a land area on PreEarth) was outside the circle.

    Heaven was completely submerged into PreEarth (causing massive expansion).

    When Pangaea (considered as a land area on PreEarth) is mapped from the sphere of PreEarth to a flat map, you get exactly the map of the first graphic up above. In fact, that is how this map was first produced.

    Here is a standard map of Pangaea



    The expansion in size of PreEarth after swallowing Heaven, caused Pangaea to spilt apart and break up into what we now call continents.

    The circular region where Heaven entered is now called the Pacific Ocean (not all the Pacific, but most of it).

    Here is an animation showing how the Atlantic Ocean opened up.

    http://preearth.net/anim-atlantic-400.gif
    (Embedded image changed to link - again. Preearth was specifically told not to re-embed an image and did so anyway.)


    and another showing the opening around Antarctica.

    http://preearth.net/anim-antarctica-400.gif
    (Embedded image changed to link - again. Preearth was specifically told not to re-embed an image and did so anyway.)


    Cool animations, eh?

    From: http://preearth.net/
    Last edited by Jim; 2010-Jul-02 at 02:30 AM. Reason: Post edited as noted

  2. #2
    Join Date
    Oct 2009
    Location
    a long way away
    Posts
    8,739
    Is this in addition to, instead of, or the same as the collision that is hypothesized to have created the moon?

  3. #3
    Join Date
    Feb 2003
    Posts
    13,080
    Preearth Welcome to BAUT. Please take some time to read the rules for posting and the advice for ATM posters. Both linked at the bottom of this post.
    Rules For Posting To This Board
    All Moderation in Purple

  4. #4
    Join Date
    Jun 2008
    Posts
    2,344
    So according to your theory on which plane was the earth struck? What was the mass of both planets?

  5. #5
    Join Date
    Jul 2005
    Location
    Boulder, CO
    Posts
    3,480
    Are you stating that the continental crust, at least in some very rough form, already existed prior to this collision, and was only cracked/fractured by the impact, forming modern plates? If so, then you are significantly underestimating the energy released by such an event. The energy released would thoroughly melt the entire surface of the earth, which would form new plates upon cooling.

  6. #6
    Join Date
    May 2010
    Posts
    29
    Quote Originally Posted by cjl View Post
    Are you stating that the continental crust, at least in some very rough form, already existed prior to this collision, and was only cracked/fractured by the impact, forming modern plates?
    Yes, indeed.

    Quote Originally Posted by cjl View Post
    If so, then you are significantly underestimating the energy released by such an event. The energy released would thoroughly melt the entire surface of the earth, which would form new plates upon cooling.

    PROVE IT.

  7. #7
    Join Date
    May 2010
    Posts
    29
    I would spend more time at your site, except I can't be bothered with the censorship.

  8. #8
    Join Date
    Oct 2001
    Location
    Clear Lake City, TX
    Posts
    9,042
    Preearth, we don't practice censorship here; we do enforce the Rules for Posting.

    You may be concerned about your second post not showing up immediately. The vBulletin software holds all posts from new Members in the Moderation Queue until a Moderator can determine it is not spam. This goes away after a certain number of posts.
    Never attribute to malice that which can be adequately explained by ignorance or stupidity.
    Isaac Asimov

    Moderation will be in purple.
    Rules for Posting to This Board

  9. #9
    Join Date
    Oct 2001
    Location
    Clear Lake City, TX
    Posts
    9,042
    Quote Originally Posted by preearth View Post
    Quote Originally Posted by cjl
    If so, then you are significantly underestimating the energy released by such an event. The energy released would thoroughly melt the entire surface of the earth, which would form new plates upon cooling.



    PROVE IT.
    Preearth, that's not the way this forum operates. You have made a claim. It has been challenged. You need to provide support for your claim.
    Never attribute to malice that which can be adequately explained by ignorance or stupidity.
    Isaac Asimov

    Moderation will be in purple.
    Rules for Posting to This Board

  10. #10
    Join Date
    Jul 2005
    Location
    Boulder, CO
    Posts
    3,480
    Quote Originally Posted by preearth View Post
    Yes, indeed.




    PROVE IT.
    Although, as Jim said, I am under no such obligation (it's actually up to you to show the energy would be insufficient), this is easy enough that I don't mind. I'll assume each object is 1/2 earth mass (and therefore ~80% the current earth radius). The gravitational potential energy of the incoming object at impact is equal to -GM1M2/R, which gives -9*1031 joules. Basically all of this would be converted to heat. Rock has a heat capacity of around 0.8 J/g/K. This means that assuming the entire mass of the earth was solidified rock (an extremely conservative assumption, as much of would have still been molten from heat of formation and radioactivity), the energy released would have been sufficient to raise the earth's temperature by over 12,000 kelvin. Even if it started at absolute zero, that would melt the entire planet.
    Last edited by cjl; 2010-May-29 at 11:21 AM. Reason: missed a factor of 2 in my calculations

  11. #11
    Join Date
    May 2010
    Posts
    29
    Quote Originally Posted by cjl View Post
    I'll assume each object is 1/2 earth mass (and therefore ~80% the current earth radius). The gravitational potential energy of the incoming object at impact is equal to -GM1M2/R, which gives -9*1031 joules. Basically all of this would be converted to heat. Rock has a heat capacity of around 0.8 J/g/K. This means that assuming the entire mass of the earth was solidified rock the energy released would have been sufficient to raise the earth's temperature by over 12,000 kelvin. Even if it started at absolute zero, that would melt the entire planet.
    You are wrong about that. Not a bad try though.

    Indeed the gravitational potential energy of the system at impact is equal to -GM1M2/R, which gives -9*10^31 joules.

    However, not all that potential energy will be converted to heat.

    A lot of this energy will be used in reshaping the 2 planets into one.

    For example, a cubic kilometer of mass on the surface of Heaven (radius 4800 km) needs to be "lifted" one and a half thousand kilometers to the surface of Earth (radius 6371 km), or more, if the cubic kilometer of mass started below Heaven's surface.

    So you get the idea.

    Its not as simple as you think.

  12. #12
    Join Date
    Jun 2003
    Posts
    7,975
    I think that demolishes Preearth's theory, which apart from the stuff about continents was fairly reasonable. The Earth almost certainly accreted from numerous smaller planetoids, and the last collision (which produced the Moon) seems to have been a collision between two objects of roughly comparable size. But the surface of the Earth was completely reconfigured in that impact.

  13. #13
    Join Date
    May 2010
    Posts
    29
    As to the question of whether the energy released by the impact would melt the entire earth.

    We will make the simplifying assumption of spherical planets with uniform density.

    This makes the math simple and the argument easy to follow.

    First we calculate the temperature rise caused by placing PreEarth next to Heaven and letting gravity transform them into the Earth.

    The gravitational binding energy of a planet, U, is the energy released by the assembly of the planet from atoms which were originally an infinite distance away. Or, alternatively, it is the energy needed to disassemble the planet into atoms by moving each an infinite distance away.

    The gravitational binding energy of a spherical planet with uniform density, is given by the formula;

    U = 0.6GM^2/R, where

    G = 6.67428 x 10^-20 km^3/(kg s^2) is the gravitational constant,
    M is the mass of the planet in kg,
    R is its radius in km.

    U is here measured in megajoules, MJ.

    Earth Radius R_E = 6371 km.
    Earth Mass M_E = 5.97369 x 10^24 kg.
    Approximate Earth Binding Energy = 0.6*G*M_P^2/R_P = 22.430 x 10^25.

    PreEarth Radius R_P = 5200 km.
    PreEarth Mass M_P = 3.48280 x 10^24 kg.
    Approximate PreEarth Binding Energy = 0.6*G*M_P^2/R_P = 9.341 x 10^25 MJ.

    Heaven Radius R_H = 4680 km.
    Heaven Mass M_H = 2.48456 x 10^24 kg.
    Approximate Heaven Binding Energy = 0.6*G*M_H^2/R_H = 5.282 x 10^25 MJ.

    The energy necessary to separate PreEarth and Heaven to infinity, is:

    G*M_P*M_H/(5200+4680) = G*M_P*M_H/9880 = 5.846 x 10^25 MJ.

    The idea is to take PreEarth and Heaven at the point of first contact, that is, when they are just 9,880 kilometers apart, dissemble them to infinity, then bring everything back from infinity and assemble Earth.

    So, the energy released from the point of contact through the formation of the Earth, is:

    Energy Released = (22.430 - 9.341 - 5.282 - 5.846) x 10^25 = 1.961 x 10^25 MJ.

    This is (1.961 x 10^25)/(5.97369 x 10^24) = 3.2827 megajoules per kilogram.

    Suppose an average specific heat of 1330 J/kgK.

    Then we have a 3282700/1330 = 2,468 degree rise in the temperature of the entire Earth.

    Note that, this is the energy released by just placing PreEarth next to Heaven and letting gravity transform them into the Earth. This does not incorporate any kinetic energy that the two original planets may have had.
    Last edited by preearth; 2010-Jun-03 at 09:47 PM.

  14. #14
    Join Date
    May 2010
    Posts
    29
    Quote Originally Posted by Strange View Post
    Is this in addition to, instead of, or the same as the collision that is hypothesized to have created the moon?
    Is this in addition to, instead of, or the same as the collision that is hypothesized to have created the moon?

    This is instead of the collision that is hypothesized to have created the moon.

    It should be pointed out that the accepted hypothesis, i.e., the hypothesized glancing collision between the Earth and a Mars sized object, has its problems.

    The oxygen-17/oxygen-18 ratio of lunar samples is indistinguishable from the terrestrial oxygen-17/oxygen-18 ratio.

    This means that the impactor had to have essentially the same oxygen-17/oxygen-18 ratio, that is, it had to be a twin (binary) of the Earth.

    http://www.lpi.usra.edu/meetings/lpsc2005/pdf/2382.pdf

    So, the Moon had to be formed from the impact of a former moon,... which is not really satisfactory at all, is it?
    Last edited by preearth; 2010-Jun-03 at 09:16 PM.

  15. #15
    Join Date
    May 2010
    Posts
    29
    Your censoring this answer will make a real good story on my website.

    Actually, I already have a reasonable story since eburacum45 posted long after me and his post was displayed yet mine was censored. I will have a story on this ready in a day or two.

    You are wrong about that. Not a bad try though.

    Indeed the gravitational potential energy of the system at impact is equal to -GM1M2/R, which gives -9*10^31 joules.

    However, not all that potential energy will be converted to heat.

    A lot of this energy will be used in reshaping the 2 planets into one.

    For example, a cubic kilometer of mass on the surface of Heaven (radius 4800 km) needs to be "lifted" one and a half thousand kilometers to the surface of Earth (radius 6371 km), or more, if the cubic kilometer of mass started below Heaven's surface.

    This takes a huge amount of energy.

    So you get the idea.

    Its not as simple as you think.

    And your censoring this answer will make a real good story on my website.

  16. #16
    Join Date
    Oct 2001
    Location
    Clear Lake City, TX
    Posts
    9,042
    Preearth, did you not bother to read either of my posts to you? I strongly urge you to do so now.

    Just to repeat, you are a new Member (Newbie). All new Members go through an initial period where their posts are held in the Moderation Queue to determine they are not spam. This is not censorship; start arguing that. It makes you look paranoid.

    Also, as the proponent of and ATM idea, the burden of proof rests with you. No one else is obligated to provide any math; you are. Provide your version of the energy calculations.

    I suggest you read the Rules for Posting (link below).
    Never attribute to malice that which can be adequately explained by ignorance or stupidity.
    Isaac Asimov

    Moderation will be in purple.
    Rules for Posting to This Board

  17. #17
    Join Date
    Jul 2005
    Location
    Boulder, CO
    Posts
    3,480
    Actually, it is exactly as simple as I think, since my calculations were for the potential energy of the system with the two spheres tangent to each other. The actual energy dissipated would be even higher, since the final coalesced sphere will have a more negative potential than a pair of spheres tangent to each other would have.

  18. #18
    Join Date
    Mar 2007
    Location
    Falls Church, VA (near Washington, DC)
    Posts
    4,921
    Let me add that the process of transforming the two spheres into one means an inelastic deformation which generates heat throughout the bodies. I cannot see any means of confining the heat to a small region around the point of initial contact. My rough calculations of the heat amount to thousands of joules per gram, which should be enough to melt the crust many times over.

  19. #19
    Join Date
    Nov 2005
    Posts
    3,456
    While I think there is a shortage of evidence that Earth formed from two (instead of many) bodies, I do think cjl's calculation is oversimplified. Why call the potential energy negative? There is a heat of melting involved = 30? calories per gram and a heat of boiling involved = 200? calories per gram, a heat of ionization = no idea. Plasma would be formed at the points of contact, which would radiate some of the heat into space as visable light and infrared, possibly lots if the two bodies bounced and collided repeatedly before assembling. There is also the speed difference which would produce additional heat. Most of the heat of boiling would melt more rock as the boiled rock condensed a day or more later, but some jets of rock gas are not improbable that might reach escape velocity and/or become NEO = near Earth objects. I agree little or none of the surface of pre Earth would remain intact unless Heaven had much higher density and thus much smaller size for approximately equal mass. The moon may have formed as a result of this impact, if it occurred. Neil

  20. #20
    Join Date
    Jun 2007
    Posts
    4,331
    Quote Originally Posted by neilzero View Post
    While I think there is a shortage of evidence that Earth formed from two (instead of many) bodies, I do think cjl's calculation is oversimplified. Why call the potential energy negative? There is a heat of melting involved = 30? calories per gram and a heat of boiling involved = 200? calories per gram, a heat of ionization = no idea. Plasma would be formed at the points of contact, which would radiate some of the heat into space as visable light and infrared, possibly lots if the two bodies bounced and collided repeatedly before assembling. There is also the speed difference which would produce additional heat. Most of the heat of boiling would melt more rock as the boiled rock condensed a day or more later, but some jets of rock gas are not improbable that might reach escape velocity and/or become NEO = near Earth objects. I agree little or none of the surface of pre Earth would remain intact unless Heaven had much higher density and thus much smaller size for approximately equal mass. The moon may have formed as a result of this impact, if it occurred. Neil
    It's simplified but not oversimplified. It's a major underestimate of the total effect, but suffices to show that the total energy released would be more than sufficient to destroy the entire surface.

    The potential energy is negative because gravitational potential energy is negative. You can't measure it relative to the center of the body because that point has a different potential energy for every body. So gravitational potential energy is considered to be zero at infinity, a far more useful common reference point.

    There would be radiated losses and heat of fusion/vaporization, but given how many times more energy is involved than is needed to melt the entire planet and the fact that a real merger would be much worse, it's reasonable to ignore them...little is gained by going into such detail. "Bouncing" and multiple collisions would indeed convert much of the initial kinetic and potential energy to heat, but the portion of potential energy used in cjl's estimate would only be released in the final merging event.

    It's clear the original poster is vastly underestimating the scale and violence of the event. Life would not survive...the gentlest such mergers would wipe out even the deep rock extremophile bacteria. The planet would be a brightly incandescent mass afterward.

    There was supposed to be a new moon formation theory in this, but none was mentioned. The presently most accepted theory is that a similar impact occurred, and was energetic enough to re-melt the entire Earth and blast a large amount of mantle material into orbit. Life didn't show up until half a billion to a billion years later.

  21. #21
    Join Date
    May 2003
    Posts
    1,258
    Hmmm... I am no expert on this, but I seem to recall that planetary size collisions would not have been possible any later than 4 gigaannums ago or so. Also, even moon forming impactor would have completely molten the earths surface, even if it had formed by that time. Actually, I should think the Earth glowed like a small star after the impact...

    As for Pangaea, it is a relatively recent continent, it was formed around 300Ma ago, but, there have been many other super-continents before that, so the OP might have meant some other of them.

  22. #22
    Join Date
    May 2010
    Posts
    29
    I have fixed up a few of the above comments.

  23. #23
    Join Date
    Jan 2005
    Location
    New Zealand
    Posts
    9,644
    Quote Originally Posted by preearth View Post
    I have fixed up a few of the above comments.
    That is called "revisionism" and is against the rules. You may edit a post for typos and such, but what you've done is change content. A thread in a forum is a linear thing, what you are doing is making people go back and read from the start - and every post made after the posts you edited may need revising. Please do not do this again.

    If you need to add more to the discussion - add a new post.
    I don't see any Ice Giants.

  24. #24
    Join Date
    Jun 2009
    Posts
    7,741
    Quote Originally Posted by preearth View Post
    I have fixed up a few of the above comments.
    Your revisionism will make for a good story on my website. (kidding)

    You seem to be rejecting plate tectonics in saying that your hypothesised planetary collision created the mountain ranges - is that correct?

    ETA: If the answer to the above is yes, can you explain where the problems lie in the plate tectonics theory?
    Last edited by Spoons; 2010-Jun-04 at 06:22 AM. Reason: add a question

  25. #25
    Join Date
    Feb 2010
    Posts
    630
    Quote Originally Posted by cjl View Post
    Although, as Jim said, I am under no such obligation (it's actually up to you to show the energy would be insufficient), this is easy enough that I don't mind. I'll assume each object is 1/2 earth mass (and therefore ~80% the current earth radius). The gravitational potential energy of the incoming object at impact is equal to -GM1M2/R, which gives -9*1031 joules. Basically all of this would be converted to heat. Rock has a heat capacity of around 0.8 J/g/K. This means that assuming the entire mass of the earth was solidified rock (an extremely conservative assumption, as much of would have still been molten from heat of formation and radioactivity), the energy released would have been sufficient to raise the earth's temperature by over 12,000 kelvin. Even if it started at absolute zero, that would melt the entire planet.
    I'm glad you decided to provide an explanation to your original post. I am interested in the reasoning of any assertion. While it is up to those posting the ATM to support their idea(s), I doubt whether it is merely sufficient for those providing an idea in opposition merely to leave it as an assertion. Thank you for taking the trouble.

  26. #26
    Join Date
    May 2010
    Posts
    29
    Let us establish some terminology:

    Continent separation is the separation of the continents under the collision hypothesis.

    Continent drift is the separation of the continents under the mantle currents hypothesis.

    The appearance of this continent separation agrees with the appearance of the continent drift in most ways.

    The hidden differences are in the mechanism and timing.

    Continent separation resulted from the expansion caused by the collision.

    In the collision hypothesis the continents were actually expanded apart.

    As the planet expanded, the continental crust cracked, molten material flowed into these cracks and widening them, in many instances, by thousands of miles.

    Thus, continental separation is not the continents physically moving over the surface of Earth, as claimed in continent drift, but the continents standing still, at their original positions on the surface, while the spaces between them expand, giving the appearance of their movement across the globe of the Earth.

    Quote Originally Posted by Spoons View Post
    You seem to be rejecting plate tectonics in saying that your hypothesised planetary collision created the mountain ranges - is that correct?
    If by plate tectonics, you mean the separation of the continents by mantle currents, then, yes, I believe that theory is incorrect.

    Quote Originally Posted by Spoons View Post
    If the answer to the above is yes, can you explain where the problems lie in the plate tectonics theory?
    There are certain standard problems such as the need to raise the whole continent of India over the equatorial bulge (in its travels from near the pole to above the equator).

    So the whole continent of India needs to be raised some 20 kilometers.

    This apparently requires more energy than shining a radioactive source at India, even for a very long time, can provide.

    Another of the well-known problems is that the rotational energy of India near the pole is small,.. but near the equator, it is large.

    Again, shining a radioactive source at India, apparently can't provide the needed energy.

  27. #27
    Join Date
    Jun 2008
    Posts
    2,344
    Quote Originally Posted by Canis Lupus View Post
    I'm glad you decided to provide an explanation to your original post. I am interested in the reasoning of any assertion. While it is up to those posting the ATM to support their idea(s), I doubt whether it is merely sufficient for those providing an idea in opposition merely to leave it as an assertion. Thank you for taking the trouble.
    cjl has provided you with some specific math on the physics of such a thing and you have only ever made a 'shoot from the hip' type of claim backed up by nothing. Do you see the difference?

  28. #28
    Join Date
    Jun 2007
    Posts
    4,331
    Quote Originally Posted by preearth View Post
    There are certain standard problems such as the need to raise the whole continent of India over the equatorial bulge (in its travels from near the pole to above the equator).

    So the whole continent of India needs to be raised some 20 kilometers.
    So why hasn't the ocean drained away from the bulge? It's a lot shallower than 20 km.

    That bulge exists in the first place because the Earth is rotating. The equator is not "uphill", despite being further from the center of the Earth. It poses no obstacle to the motion of India or any other plate.


    Quote Originally Posted by preearth View Post
    This apparently requires more energy than shining a radioactive source at India, even for a very long time, can provide.
    Who says that plate motion is caused by "shining a radioactive source" at the plates?


    Quote Originally Posted by preearth View Post
    Another of the well-known problems is that the rotational energy of India near the pole is small,.. but near the equator, it is large.
    Wait, you just said continents couldn't move uphill toward the equator, now you're saying they couldn't move uphill *away* from it?


    Quote Originally Posted by preearth View Post
    Again, shining a radioactive source at India, apparently can't provide the needed energy.
    Again, how does that matter? Plates are pushed around by convection currents in the mantle, not by beams of radiation.

    Even if your points about the equator and mountains were valid, the energy expended in those actions is dwarfed by that involved in the convection of the mantle. Do you have any idea how many times over the mantle out-masses the crust?

    Your proposals display both a deeply lacking sense of the scales involved, as well as a severely lacking understanding of what the mainstream theories are and what the evidence for them is. Do you have any idea how tiny mountain ranges are on the scale of the planet? Do you realize that, to provide the energy to lift some tiny bits of rock a miniscule fraction of the planet's radius, you're proposing an event that by definition released at least enough energy to split the planet in half?

    Following the collision you propose, can you explain how Earth would not be completely molten, with all liquid water long gone, and with an atmosphere of steam and rock vapor?

  29. #29
    Join Date
    May 2010
    Posts
    29
    Quote Originally Posted by cjameshuff View Post
    Quote Originally Posted by preearth View Post
    Again, shining a radioactive source at India, apparently can't provide the needed energy.
    Again, how does that matter? Plates are pushed around by convection currents in the mantle, not by beams of radiation.
    What is meant to power the supposed mantle currents?

    The temperature gradient. Yes?

    What is the source of the temperature gradient?

    Well, it is supposed to be, residual heat from the formation of the Earth and heat from radioactive decay.

    So, it is fair to say that the supposed convection currents are powered by a radioactive source (that is less radioactive than your surroundings) by just letting it shine long enough (hundreds of millions of years) for the energy to build up to the desired amount.

    The amount of "radioactive shine" is much, much less than sunshine on a dull day. If you let sunshine on a dull day, shine on India for hundreds of millions of years, it too would raise the Himalayas?

    Your other comments have merit. Obviously, I am not totally against some sort of continent drift, and I have not given the ideas concerning India traversing the bulge, etc, much thought.

    Quote Originally Posted by cjameshuff View Post
    Following the collision you propose, can you explain how Earth would not be completely molten, with all liquid water long gone, and with an atmosphere of steam and rock vapor?
    Yes. See a previous comment.

    The opening of the South Atlantic.

    http://preearth.net/anim-south-atlantic-400.gif
    Preearth, you have been warned before to not embed a large image in your posts! I have changed this to a link (as was done in your earlier post) and those interested in seeing your animation can click it. Do not change it back!

    Yet another cool animation, eh?

    From:
    http://preearth.net/
    Last edited by Jim; 2010-Jun-09 at 01:36 AM. Reason: changed embed to link, added note

  30. #30
    Join Date
    Jun 2007
    Posts
    4,331
    Quote Originally Posted by preearth View Post
    So, it is fair to say that the supposed convection currents are powered by a radioactive source (that is less radioactive than your surroundings) by just letting it shine long enough (hundreds of millions of years) for the energy to build up to the desired amount.

    The amount of "radioactive shine" is much, much less than sunshine on a dull day. If you let sunshine on a dull day, shine on India for hundreds of millions of years, it too would raise the Himalayas?
    This is a nonsensical comparison. It's radioactive decay throughout the interior of the planet, not beams of radiation shining on the plates (and as a matter of fact, the radioactivity within the Earth is *higher*, not lower than that at the surface, as radioactive heavy elements are relatively uncommon on the surface). But, sunlight shining on a patch 1 km square, taking into account the rotation of Earth and night periods, delivers enough energy to raise a 1 km cube of granite by 1 km over just 2.5 years, about 4.5 cm/hour.
    ((2.75 g/cm^3)*(1 km)^3*9.8 m/s^2*1 km)/(342 W/m^2*(1 km)^2) = 2.5 years

    The current total power output of radioactive decay within the Earth is estimated at 30 TW, enough to lift a 1 km cube of granite at about 1 m/s. Enough, in fact, to lift an entire Earth-mass of material (a mass many, many times greater than that of the crust alone) in a 1 g field 16 km over 1 billion years. And it used to be higher, a lot of radioactive material has decayed over the billions of years Earth has existed.

    Really, what makes you think currents in a mass of solid and semi-molten rock almost 3000 km deep floating on a sea of iron another couple thousand km deep couldn't push up a few little 7-9 km tall bumps on the surface? The mere fact of mantle convection shows there's no shortage of energy, the limit on mountain height is largely material strength. Your sense of scale needs some major readjustment.


    Quote Originally Posted by preearth View Post
    Yes. See a previous comment.
    A claim that it happened is not an explanation of how it could have happened. There's just no way to allow a gentle merger of the sort you wish for.

Similar Threads

  1. Why don't gas planets coalesce in to solid planets?
    By SanitysEdge in forum Astronomy
    Replies: 58
    Last Post: 2011-Mar-24, 05:46 PM
  2. Earth sized moons oribiting Jovian sized planets
    By cadoom in forum Space/Astronomy Questions and Answers
    Replies: 20
    Last Post: 2009-Apr-21, 04:12 PM
  3. NASA Dreams Up Exotic Earth-Sized Planets
    By Fraser in forum Universe Today
    Replies: 2
    Last Post: 2007-Oct-19, 07:36 PM
  4. Earth-Sized Planets Could Be Nearby
    By Fraser in forum Universe Today
    Replies: 13
    Last Post: 2006-Dec-22, 06:04 PM
  5. Earth-Sized Planets are Probably Common
    By Fraser in forum Universe Today
    Replies: 0
    Last Post: 2006-Sep-08, 09:19 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
here
The forum is sponsored in-part by: