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Science

Earth, a Giant Pinball Machine 19

An anonymous reader writes "Scientists have long probed Earth's interior by monitoring seismic waves (if earthquakes don't make them, they can be induced with explosives, and one nuke test actually triggered an earthquake!), which reveal the inner structure of the planet. But what if the method is wrong? LiveScience reports on a new study suggesting Earth is like a pinball machine, with sound waves careening around before they get to the surface. What is interpreted as a broad layer change could be nothing more than a localized density variation."
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Earth, a Giant Pinball Machine

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  • by horati0 ( 249977 ) on Saturday November 20, 2004 @04:20PM (#10876534) Journal
    i hate it when a broad layer change turns out to be a localized density variation!
  • The core (Score:2, Funny)

    by oz_ko ( 571352 )
    Nooooooooooooooo..... don't mess with the Earth's core. Don't you know it'll stop spinning and then we'll be all stuffed.

    We'll have to watch the movie "The Core" to the end to see how we fix it and that willl cause the extinction of our species.

  • by palndrumm ( 416336 ) on Saturday November 20, 2004 @05:43PM (#10877007) Homepage
    But what if the method is wrong?

    If the method is wrong, then our model of the Earth's interior will most likely be wrong. If that's the case, as we continue to gather more data in greater detail, it will become increasingly obvious that the data doesn't fit the model. Once we reach that point, we will either adjust the current model, or create a completely new model, that the data fits the model once again.

    In other words, it'll be business as usual for the scientific method...
    • But we've been using the current method for a long time. What happens if we adjust the model instead of changing of our method, resulting in a new model which appears to work for a long time. In the meantime this discovery is determined not to be correct.

      Eventually it is almost forgotten, but remembered just well enough that anyone who it occurs to, and checks, will see that someone else already thought of that and the theory was found to be incorrect (since it clashed with our new false model).

      Sure som
      • How is this a troll? If our method is wrong, but we just adjust the model (it's not exactly relevant here because the actual problem is not accurately described in the article), we may still get the approximation to reality incorrect.

        The problem is simply that the solutions generally found are not necessarily unique, if one assumes a very simple model and doesn't apply additional, independent knowledge to the problem.

        However, as another person posted, the reality is that "we've" been doing a pretty good
    • our model of the Earth's interior

      "For the world is hollow and I have touched the sky"

      I can't see the words "Earth's interior" without thinking of that title. : )

    • I dare to imply that Occum's razor and the scientific method could need reform, even giving a reasonably likely situation in which this could occur. And having done so makes me a troll?

      The scientific method coupled with peer review is wonderful, it has brought us far. Unfortunately it is inherently flawed.

      It is flawed because the scientific method relies on the belief that when all evidence is presented the conclusion one logically arrives, which fits all said evidence and symptoms, is the correct one.
      • While I don't think you were trolling before, I do think you have some problems with your premises:

        1) There is no assumption that we will find the perfectly correct solution to a problem. The assumption is that we will get so close with approximations to the exact solution that for all intents and purposes it'll be "right". There's a difference--one implies that science can get to the "absolute truth", and the other implies that science can provide a working model that is very close to reality.

        2) There
        • "Yes, humans are flawed, but that doesn't mean our method of producing valid approximations to reality haven't been useful. That doesn't mean we don't understand ANYTHING about our universe."

          I certainly never said we didn't produce anything, I said the opposite. I said our current method was a cheap hack that has resulted in us producing MORE in a short period of time than we would without it. The problem isn't in what we've produced, the problem is you can only build a house of straw so tall before it col
          • I don't agree that the current (ideal) scientific method is a cheap hack. There is no reason to think that the current method of reviewing scientific "fact" is going to cause some kind collapse of science. The scientific method has built-in safeguards against the kind of problems that plagued the dark ages. It expectsto have basic, foundation theories revamped or replaced from time-to-time.

            However, there are also established facts that are observations, not theories. These observations may be explaine

  • by BortQ ( 468164 ) on Saturday November 20, 2004 @08:03PM (#10877879) Homepage Journal
    Bah! This is just LiveScience trying to scam us to keep on feeding in the quarters.
  • If this is true. (Score:3, Informative)

    by Murphy Murph ( 833008 ) <sealab.murphy@gmail.com> on Saturday November 20, 2004 @08:39PM (#10878067) Journal
    If this is true - and their experiment with the slab of aluminum offers decent evidence - why do modern seismological methods work as well as they do?

    Money is the prime driver in many forms of research, and nobody has as much money vested in geologic surveys as the oil companies. Why haven't they already discovered this effect?

    Question: Do seismic surveys currently employ a Radon transform (like how CAT scans reconstruct a 2D image from 1D projections)? If so, how would this "pinball effect" affect that?

    • Re:If this is true. (Score:2, Informative)

      by mopomi ( 696055 )
      Yes, they typically employ a Radon transorm during the inversion. Seismology is very much like a CAT scan w.r.t. methodology. The problem described in the paper ( http://acoustics.mines.edu/preprints/vanwijklevsh in04.pdf [mines.edu]) is that the multiple scattering caused by small heterogenieties near the surface of an object can cause the same sort of signal (to within error) as a multiply layer object. The radon transfer will have just as much of a problem as any other inverse transform simply because the matrix
  • Since the submitter talked about a giant pinball machine, here's the world's smallest pinball machine [chalmers.se]
  • East L. (Score:4, Funny)

    by Tablizer ( 95088 ) on Sunday November 21, 2004 @02:10PM (#10881948) Journal
    In a typical survey, geologists generate seismic waves, typically tens to hundreds of yards (meters) long, by igniting sticks of dynamite underground or vibrating the surface with a large, bouncing truck on hydraulic suspension.

    And you thought low-riders were all play.

Never test for an error condition you don't know how to handle. -- Steinbach

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