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Space Moon

Evidence of Protoplanet Found On Moon 105

Posted by samzenpus
from the back-in-the-day dept.
mrspoonsi (2955715) writes 'Researchers have found evidence of the world that crashed into the Earth billions of years ago to form the Moon. Analysis of lunar rock brought back by Apollo astronauts shows traces of the "planet" called Theia. The researchers claim that their discovery confirms the theory that the Moon was created by just such a cataclysmic collision. The accepted theory since the 1980s is that the Moon arose as a result of a collision between the Earth and Theia 4.5bn years ago. It is the simplest explanation, and fits in well with computer simulations. The main drawback with the theory is that no one had found any evidence of Theia in lunar rock samples. Earlier analyses had shown Moon rock to have originated entirely from the Earth whereas computer simulations had shown that the Moon ought to have been mostly derived from Theia. Now a more refined analysis of Moon rock has found evidence of material thought to have an alien origin.'
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Evidence of Protoplanet Found On Moon

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  • It is the simplest explanation, and fits in well with computer simulations.

    Oh heck no: turtles all the way down, biz-rotches!

    • I thought the simplest explanation was that it was captured by Earths Gravity
      • by modmans2ndcoming (929661) on Friday June 06, 2014 @08:26AM (#47178343)

        Earth isn't large enough to capture an object the size of the moon in such a close orbit. and the moon was orbiting in a much much closer orbit 4 billion years ago.So, no, it was the most complex explanation.

      • by Z00L00K (682162)

        Also consider that the proto-earth and Theia originated from the same material overall, which means that it would be hard to distinguish them from each other.

      • by Rockoon (1252108) on Friday June 06, 2014 @11:07AM (#47179631)

        I thought the simplest explanation was that it was captured by Earths Gravity

        Thats only simple until you figure out that that sort of thing isnt actually possible. In cases where gravitational capture is possible, it is the gravity of a 2nd body (such as a moon) that enables a 3rd body (such as an asteroid) to lose enough velocity to orbit a 1st body (such as a planet.) Conservation of energy means any body that wasnt in a planets orbit will by default have escape velocity if it ever approaches that planet, and this is true unless it is acted upon by a force external to the mutual gravity of the planet and would-be capturer.

        • Yet pop the astronomy books that I read my children are full of moons being captured. I've never gotten that.

          • by RockDoctor (15477)

            Yet pop the ["the pop", surely?] astronomy books that I read my children are full of moons being captured. I've never gotten that.

            The people writing the pop astronomy books haven't actually studied the subject in sufficient depth. They're just parroting something they got from a popular astronomy book in the 1950s.

      • by rgbatduke (1231380) <rgb@nOSpAM.phy.duke.edu> on Friday June 06, 2014 @01:00PM (#47180849) Homepage

        Damn, I had to give up modding this to answer, but I can't leave this.

        One cannot "capture" a body the size of the moon by any two body elastic (e.g. gravitational) interaction. Within irrelevant perturbations such as gravitational wave radiation (presuming such a thing to exist), energy is conserved, and if it starts out unbound to the Earth it will end up unbound to the Earth.

        One can capture in a three (or more) body interaction, but in that case the missing energy has to go someplace, and we are talking about a LOT of energy in the case of an orbiting moon. Enough energy to basically melt the moon and the earth and then some. One would expect to see some sort of orbital remnants of such a many-body event, and all of the other bodies in the solar system are a bit too far away to be good candidates in terms of the forces needed, and show none of the orbital perturbation one would expect as a consequence.

        That leaves inelastic events. Tidal interaction is inelastic over time, but to make it strong enough to mediate a "capture" it would damn near be a collision anyway, brushing up on Roche's Limit (look that up). Also, that too would leave the nascent moon in an orbit much closer than the initial radius of its apparent orbit. Also, it wouldn't explain the apparent deficit of heavier elements and an iron core in the moon (thought to have been literally blown out of the incoming body in the collision and either ejected altogether to carry away the missing energy and momentum needed to leave the remnant in orbit or absorbed into the Earth) and a bunch of other things.

        So really, the collision hypothesis makes "enough" sense and is consistent with enough data that it is AFAIK the "accepted" explanation of the moon's origin, with the usual caveat that contrary evidence or a better argument in the future might change that as we cannot easily be certain about events 4.5 billion years ago.

        rgb

  • Somewhat confused (Score:5, Insightful)

    by ocean_soul (1019086) <tobias.verhulst@NospaM.gmx.com> on Friday June 06, 2014 @05:43AM (#47177891) Homepage

    I haven't read the Science article yet, but from the BBC report it seems that the differences between the isotope ratios in moon rocks and earth are still a lot smaller than expected. This would suggest the Theia hypotheses to not be true, contrary to what the title says. I'm going to track down the original paper, because this BBC article has me somewhat confused.

    • Re:Somewhat confused (Score:5, Informative)

      by PhilHibbs (4537) <snarks@gmail.com> on Friday June 06, 2014 @05:58AM (#47177925) Homepage Journal

      I haven't read the Science article yet, but from the BBC report it seems that the differences between the isotope ratios in moon rocks and earth are still a lot smaller than expected. This would suggest the Theia hypotheses to not be true, contrary to what the title says. I'm going to track down the original paper, because this BBC article has me somewhat confused.

      The absolute terms "true" and "not true" are not appropriate for a hypothesis like this. There may be some parts of it that are accurate, but for instance the size, mass, velocity, density distribution etc. of the Theia might be wrong, or the physics in the simulation might be wrong, etc.

    • Re:Somewhat confused (Score:5, Informative)

      by Sockatume (732728) on Friday June 06, 2014 @06:17AM (#47177967)

      The isotope ratio is more different than you'd expect for formation without an impact by a third body, but it's less different than you'd expect from an impact given what we know about the distributions of oxygen isotopes in the solar system. So both hypotheses need revision: for the Theia hypothesis, they suppose that it was an inner planet with a remarkably similar composition to Earth, and for the non-impact hypothesis, they suppose that the Earth's isotope ratio diverged from that of the moon due to later (small) impacts delivering different compositions.

  • Everyone knows the moon is made of cheese!

  • I'm ignorant, but today's science seems like "Tell me what is your theory, and i will find data to prove it's true"...
    Or as a law predicts, "Given an enough amount of data, ANY theory can be proved"... :-)

    • Re:I'm ignorant (Score:5, Insightful)

      by Anonymous Coward on Friday June 06, 2014 @06:31AM (#47178003)

      I'm ignorant, but today's science seems like "Tell me what is your theory, and i will find data to prove it's true"...

      Yes, like that famous current scientist Einstein produced a theory of gravitation and then several years later they found data to prove it was true.

      Or as a law predicts, "Given an enough amount of data, ANY theory can be proved"... :-)

      There is no law that predicts such a thing. Given enough data, almost all theories are disproven. The only ones that remain are the ones that fit the data.

      • Re:I'm ignorant (Score:5, Insightful)

        by paiute (550198) on Friday June 06, 2014 @06:46AM (#47178031)

        Given enough data, almost all theories are disproven. The only ones that remain are the ones that fit the data.

        Given enough data, almost all hypotheses are disproven. The ones which remain and have not yet been disproven by evidence become theories.

        • "become theories"

          "I KNEW it!" he said conspiratorially.
        • by Anonymous Coward

          That's not quite it either. The theory is a theory from the start, assuming it makes any concrete and testable predictions. What you disprove (or eventually accept) is the hypothesis that the theory is correct.

          • Where did you learn science? Home School creationism?

            Observation of actual phenomena (evolution) ->Hypothesis of the mechanism of observed phenomena (Natural selection, genetic mutation, etc) -> Test, Test, Test, Test, Test ->Mechanism is stated to be a theory by consensus ->Test-> (maybe) revise theory -> (and on we go)

            • by beelsebob (529313)

              No, this is simply the definition of a theory. If it's simply "I think that mice cause global warming", that's a hypothesis, but as soon as you add "you could test this by doing this, this and this, it predicts this result from the above tests" it becomes a theory. Once you do the testing it may stay a theory, or become simply wrong.

            • by narcc (412956)

              Where did you learn science? A blog written by a home-schooled creationist?

              The bumper-sticker version: An hypothesis is a testable prediction. A theory is a predictive model.

              One does not graduate in to the other. A theory is a theory from the beginning.

              You're likely just confused by the question of what makes a theory a scientific theory. For that, I'll direct you to Karl Popper.

        • by alexhs (877055)

          Given enough data, almost all theories are disproven. The only ones that remain are the ones that fit the data.

          Given enough data, almost all hypotheses are disproven. The ones which remain and have not yet been disproven by evidence become theories.

          Nope, the AC was right.

          By your definition, there is ultimately no such thing as a theory. Newtonian physics don't fit as they've been invalidated by Einstein's general relativity, which itself is known to be wrong as it is inconsistent with quantum mechanics (which are also wrong for the same reason).

          You can't claim that former theories that were refined / invalidated never were theories in the first place : The "not yet" in your second sentence is problematic as it only allows theories to be defined with h

        • by beelsebob (529313)

          No, you're misunderstanding what a theory is. A theory is merely a hypothesis that has a well understood method of disproving the hypothesis.

        • by Ihlosi (895663)
          The ones which remain and have not yet been disproven by evidence become theories.

          Newton's theory of gravity has been disproven and it's still a theory. Some theories are more equal than others, especially if they're good enough for many cases and much simpler than a more correct alternative.

        • by radtea (464814)

          Given enough data, almost all hypotheses are disproven. The ones which remain and have not yet been disproven by evidence become theories.

          Science is the discipline of publicly testing ideas by systematic observation, controlled experiment, and Bayesian inference. The last one is important, because Bayesian inference never "proves" or "disproves" anything in the Cartesian (or Poperian) sense of those terms. It instead increases or decreases the plausibility of propositions.

          At best, "proof" and "disproof" are convenience terms that mean "overwhelmingly plausible with no alternative that has remotely similar plausibility" and "hugely implausible

        • by narcc (412956)

          The ones which remain and have not yet been disproven by evidence become theories.

          Wow, not even close.

      • by njnnja (2833511)

        With four parameters I can fit an elephant, and with five I can make him wiggle his trunk.

        - John von Neumann

        Von Neumann said it; that's close enough to a law for me!

        • Well, parameters are something else, eg. coefficients in a function or the color of jelly beans [xkcd.com].

          The more arbitrary parameters a theory includes, the easier it becomes to make it fit the data regardless of whether it makes any sense.

    • You could have saved us a lot of time and just stopped after your first sentence.

  • Skeptics (Score:5, Interesting)

    by Dan East (318230) on Friday June 06, 2014 @06:00AM (#47177929) Homepage Journal

    And the rest of the article discusses the skepticism of this "evidence". To sum it all up, the evidence is the different ratios of oxygen isotopes found between 3 moon rocks and Earth. Most experts are saying the difference in the ratios should be much, much larger, because of how different the ratios of isotopes are in meteorites and other outer solar system bodies. The difference between the earth and moon is so small that other theories are just as likely for explaining it. The counter argument is that maybe all of the inner planets have the same ratios of oxygen isotopes as one another, and it was an inner planet that struck Earth and basically everything involved was made of the same stuff so the differences are small.

    I think that until we have actually measured the ratios from Mecury or Venus, we can't assume that every inner planet is exactly the same in that regard, and thus the "evidence" this study has found is actual evidence one way or another. The only thing we know for certain is all the extraterrestrial material we have analyzed so far from the rest of the solar system has had very different ratios of the isotopes, and so this evidence requires a whole new theory about the homogeneousness of the solar system to be true.

    • Re:Skeptics (Score:5, Interesting)

      by C0R1D4N (970153) on Friday June 06, 2014 @07:14AM (#47178095)
      Considering the nature of the impact it is also possible that most of Theia is here on Earth under the Pacific or something while the moon is made up more of jettisoned Earth pieces. Or that the original Theia pieces make up the core/underground bits of the Moon with a tasty Earth frosting.
      • Re:Skeptics (Score:5, Interesting)

        by Charliemopps (1157495) on Friday June 06, 2014 @08:11AM (#47178235)

        The impact simulations kind of rule that out. I'd say the sample size is a real issue though. Also, there are quite a few assumptions that I'd say are questionable. We've no idea where this protoplanet came from. It could have been from outside the solar system... or it could have been part of earth at one time, jettisoned in a previous impact and came back for revenge. The fact that we have as much information as we do blows my mind. Science is amazing.

      • by sFurbo (1361249)

        it is also possible that most of Theia is here on Earth under the Pacific or something while the moon is made up more of jettisoned Earth pieces.

        AFAIK, not according to the computer simulations, which is what backs up the Theia hypothesis.

        Or that the original Theia pieces make up the core/underground bits of the Moon with a tasty Earth frosting.

        Again, I don't think this is compatible with the simulations.

      • With Deep Space Sprinkles on top
      • The pacific is the product of plate tectonics and has nothing to do with an impact crater.

        • I beleive he is using "is here on Earth under the Pacific or something " as a proxy for the phrase, "place we haven't conducted the appropriate testing at with the appropriate level of accuracy." Effectively, making it as it it were covered by miles of water, for the purposes of the known data set.

    • Re:Skeptics (Score:4, Interesting)

      by radtea (464814) on Friday June 06, 2014 @09:16AM (#47178651)

      The only thing we know for certain is all the extraterrestrial material we have analyzed so far from the rest of the solar system has had very different ratios of the isotopes, and so this evidence requires a whole new theory about the homogeneousness of the solar system to be true.

      Not exactly. One thing missing from the popular discussions of this question is why we believe that isotope ratios necessarily vary across all larger bodies in the solar system.

      It is true that measurements on meteorites show different ratios from what we see on Earth, but no particular conclusion can be drawn from that. It certainly does not follow from "None of the people I measure are the same height" that "No two people anywhere are the same height", so it would be bizarre in the extreme to go from a sample of fairly odd, mostly non-planetary, space rocks to a sweeping generalization about what is necessarily the case across the whole solar system. There may be some theoretical reason for believing this to be the case, but I've never seen it mentioned in any of the articles on this subject.

      Furthermore, Theia has a very, very special property: its orbit intersected that of Earth's almost instantly after its formation. This is not the case with meteors, which have been wandering the solar system for more than four billion years, and therefore likely formed in very distant regions. Theia almost by necessity formed in a similar orbit to that of Earth. We know this, because only a body that formed in a similar orbit would likely find itself in a collision with Earth almost immediately after formation.

      None of this "proves" or "disproves" anything, mind, because we're talking about knowledge here, not faith. Knowledge is by its nature uncertain, and the quest for certainty is simply an error pursued by pre-scientific peoples (philosophers), no different from the alchemical pursuit of transmutation of base metals into gold, or attempts to build perpetual motion machines, or attempts to trisect angles with nothing but straight-edge and compass.

      • Well said. Sometimes it sounds like they're too eager to jump to conclusions because it's the result they want.
    • by T.E.D. (34228)

      Mostly right, but you are glossing over Mars, which I think is the really big deal. It shouldn't shock anyone that Kyber belt objects have a very different composition than earth rocks. Nothing out there looks much like Earth at all. But Mars is one of the inner planets. The fact that rocks from Mars *also* look way different tells us that either *every* planet can be expected to have its own unique compositional "fingerprint", or that for some unexplained reason Mars (the one rocky planet we've been able t

      • by Anonymous Coward

        That's Kuiper, not Kyber. Named for one of the most famous american astronomers.

        See : http://en.wikipedia.org/wiki/Gerard_Kuiper

        • by T.E.D. (34228)
          Lol, you're right.

          That's why I really don't like it that Google automatically assumes you meant something else when it figures you misspelled something, and takes you to the "right" search. If you don't notice the "Showing results for kuiper belt Search instead for kyber belt" at the top in your haste for looking at the results, you're apt to think your misspelling/bad memory was right.

    • by RockDoctor (15477)

      The counter argument is that maybe all of the inner planets have the same ratios of oxygen isotopes as one another, and it was an inner planet that struck Earth and basically everything involved was made of the same stuff so the differences are small.

      As T.E.D says down thread, you're glossing over, or unaware of, the evidence form Mars. We have in situ measurements of the properties of Mars' atmosphere which allows us to unambiguously [*] flag certain (I think a couple of dozen, but the number is increasing

  • by DrXym (126579) on Friday June 06, 2014 @06:19AM (#47177975)
    ... where all those pesky Thetans came from
  • This means two things: firstly we can now be reasonably sure that the Giant collision took place; secondly, it gives us an idea of the geochemistry of Theia
  • by ArcadeMan (2766669) on Friday June 06, 2014 @08:43AM (#47178441)

    Researchers have found evidence of the world that crashed into the Earth billions of years ago to form the Moon.

    And that's how baby planets are made.

  • Okay, so these rocks are found on earth and the moon. So um...how do we know they're alien? And not native to the Earth/Lunar system?

  • [excerpts from Secretary of State testimony before the UN]

    "... Numerous sources tell us that they are moving, not just documents and hard drives, but Protoplanet fragments to keep them from being found by inspectors. [...] In this next example, you will see the type of concealment activity [...] We must ask ourselves: Why would the Moon suddenly move equipment of this nature before inspections if they were anxious to demonstrate what [evidence of Protoplanet impact] they had or did not have? [...] While thi

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  • If the theory is correct, then Earth was created by a collision of two hunks of rock, neither of which was the Earth in any meaningful sense. I'd imagine that everything we have is substantially different from either of the original masses: different surface (because the old ones were utterly scrambled), different orbits (because it seems unlikely that orbit.a + orbit.b == orbit.either_one), different compositions (because TFA says they were made out of slightly different stuff).

    It's not like the Earth was

  • Just a thought, but if there was a major impact from another planet, wouldn't we see a lot of that planet here on earth? Seems odd that they would just find it on the moon.
    • by camazotz (1242344)

      Just a thought, but if there was a major impact from another planet, wouldn't we see a lot of that planet here on earth? Seems odd that they would just find it on the moon.

      Yes, but the Earth is a geologically active world with a lot of churn, an atmosphere and constant active chemistry going on. The moon changes very little over the course of its life outside of occasional impacts. Barring that issue, I think from what i recall the Theia collision theory models around the idea of a large planet effective broadsiding Earth, and pulling off a significant chunk of crust as it does so. The models all seem to suggest that the vast majority of the debris forms the moon itself, whi

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