Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Is this idea new?

  1. Jun 12, 2008 #1
    I was sitting in my recliner when I was struck by a thought. That sometimes happens.
    Is the reason that plate tectonics exist is because we have the moon?
    It's conceded by most that the moon's construction was the crash of a proto-planet into Earth. It's contents are principally the same as the remaining crust of Earth.
    Since this collision tore off so much of Earth's crust, is this why we have plate movement? Essentially the Earth's crust was debulked and lessening the energy requirements to allow movement. Would internal convection processes be sufficient to provide that movement with the added cladding? Would retained heat eventually cause cataclysmic changes due to the added insulation?
    Other questions derive from this. Would the Earth be Venus-like if this had not taken place? Would an enormous atmosphere exist? Are plate tectonics a principle driver to evolution? To Life and intelligence itself?
    It shadows arguments concerning the moon's tidal influences on these emergences.
    If this is a valid, testable theory, I claim it.
    It may also explain why ETIs have not communicated with us. The sheer chance shearing of the bulk of our crust into an orbiting body has to be a minimal.
    Crustal thinning gives us access to metal. A principal means for technological advancement within our human paradigm.
    If this concept has been worked on previously, please inform me. I'd like to read up on it.
  2. jcsd
  3. Jun 12, 2008 #2
    it appears that you have an awful lot to learn. Take this for instance:


    There isn't any claiming going on in geo-science. Afred Wegener did not claim having discovered plate tectonics. Neither did Galilei for kicking the Earth out of the centre of the universe. Regardless the remote chance that new ideas (this isn't) could be a bit true or not, you'd have to fight for getting somebody to listen.
  4. Jun 12, 2008 #3


    User Avatar
    Gold Member

    I always had the impression that it wasn't so much a tearing off of the crust as a complete and total melting of both bodies. The amount of frictional heating involved in a collision like that would reduce most if not all of the planet and moon to a molten body, and crust formation would start again from scratch. I don't know if anyone's sure if the bodies that collided to form the earth and moon had plate tectonics.

    I don't follow you here.

    I've heard this argued before. I think it was in a book called Rare Earth by Ward and Brownlee.

    Agreed. I don't think anyone is claiming that's what happened.
  5. Jun 12, 2008 #4
    OK, perhaps I wasn't clear.
    After the planetesimal collision the Earth was diminished by some amount of material. This appears to have been selective as to the type of material. The Moon's material is this set of substances.
    The Moon consists of light weight rock and a small core of heavier material, probably iron. Since the Moon is of some size (2.2 10x10 kmx3), if this amount of material had not left the Earth the crust would be thicker. The natural sorting of denser in and lighter out would have caused this.
    If the crust was thickened by this amount would this have had a profound impact on geological processes.
    I think so.
    The active zone of the non-liquid crust of the Earth is about 6.5 10x6 KMx3. (40000 km (D) x 4 x 40 KM. Circumference (2r x Pi) x 4 x depth. ). The Moon has 2.2 10x10 KMx3 of this material, several magnitudes greater than the content of the plates using a generous understatement.
    Which brings me back to the original posit. Would this added amount of light rock affect the movement of the plates.
    Incidentally, while the math may be beyond me to calculate the differences, the thought experiment holds validity. The citations provided are not immediately related to this modification of the current reality. I was not speaking of Lunar tidal interactions (as there would not be a Moon), current tectonic plate movement (as the plates would be modified), effected planetary obliquity (as no moon would exist locally) nor current lithospheric convection (as the convective layers would be greatly thickened).
    I am speaking of a change to the parameters which I do not believe has been done before. It may further explain the uniqueness of this twin planet and how it's dynamism has produced this set of current conditions.
    I am willing to learn but there must be a relevance to the question I ask.
    Now to my other (friendlier) replier.
    I did not state that only the crust was removed or that a new crust would not emerge. I did say what would have happened if the crust was considerably thicker. The moon has considerable bulk which would have remained as added plating (it's not dense) to the Earth. If we added the mass of the Moon (7.4 x 10x22 Kgs) to the plates would there be plates? Would it have been a solid mass? The only way for the planet to release heat may have been totally different.
    When we had the pan-continent, life was limited as to it's spread due to the severity of it's climates. If the moon had not taken so much of our surface material would the Earth have a permanent frozen crust. A crust where metal was scarce except near meteor strikes and volcanic activity. Heck, would the crust thickness have prohibited many volcanoes? Would there have been many more due to increased insulation?
    As stated, I have not seen anyone explore this idea. (I still haven't.)
    If there is someone knowledgeable of such research, cloud watching or a good Sci-Fi tract, mention it please.

    As a side note, I have a playful attitude toward most things. I would claim this idea to be mine, if it's original. I would like to say that the person who develops it can enjoy whatever benefit that can be derived from it. This is just horseplay to me.
  6. Jun 14, 2008 #5


    User Avatar

    Staff: Mentor

    1. The moon is made mostly from material in the earth's mantle, not crust.
    2. All the metal mined on earth is located in the earth's crust.
    3. No, this is nowhere close to being a scientific theory, it is more like free-form, idle speculation.
    4. We don't allow free-form, idle speculation here, so I'm going to have to lock the thread.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Is this idea new?
  1. New Elements? (Replies: 4)

  2. M6.4 Papua New Guinea (Replies: 1)