Earth, a Giant Pinball Machine

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."

Comments

fooled again

[horati0]

i hate it when a broad layer change turns out to be a localized density variation!

The core

[oz_ko]

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.

If it's wrong, we'll fix it...

[palndrumm]

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...

Re:If it's wrong, we'll fix it...

[shaitand]

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 someday we would probably figure it out, but how long would it take to rediscover the correct solution? How long would mankind of have been robbed of true knowledge by Occums razor?

Re:If it's wrong, we'll fix it...

[mopomi]

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 job for a while, and the reason is that "we're" not doing seismology blindly--there is other information that helps to correct misunderstandings or non-uniqueness to JUST the seismological data.

For example, knowing the chemical composition or temperature (e.g., from volcanic eruptions) helps to pin down the more accurate solution to the seismic data.

Also, the experiments were done with a single wave source, and generally we use multiple sources, which will help to clarify the structure of the region of interest.

The structure of the Earth is very similar to what we "see" using the combined data sets that make up "seismological remote sensing".

Re:If it's wrong, we'll fix it...

[shaitand]

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.

The problem with that is that all the cards don't always have only one possible resolution, even if there is only one we can think of at the moment. It's perfectly possible for an incorrect premise to yield correct results. It's perfectly possible for it to do so for 5000 yr, or 10,000, or 10,000,000. The more cards are on the table, the more closely that incorrect premise will be to the FUNCTION of the correct premise but the cards are not always enough to reach the correct premise. The closer the function of false premise is the function of the correct premise, the longer it takes for a decidedly provable evidence of falsehood to appear.

I submit the following premises.

1. The scientific method is flawed due to the assumption that all evidence which can be collected will ultimately yield a correct premise.

2. The closer a false theory is in FUNCTION to a correct theory, the longer it takes to discover a discrepancy in the theory.

3. A false theory which has been adjusted to provide a function which fits new evidence is no closer to being a correct theory, contrary, it is closer to providing the FUNCTION of the correct theory, this in turn triggers assertion 2.

4. Man is inherently flawed, possibly due to our short lifespans and the inevitability of death, and believes that a premise which has not been disproven given a length of time should be attributed credibility.

5. When a premise has attained credibility, other premises that depend on a solution to the evidence it appears to solve will rely on it more and more blindly. This results in more false premises which are close in function to correct premises.

6. Premises arrived at via premise 5 can be correct or incorrect, because they are based on the function of the original premise. This can make the original false premise more difficult to discover.

7. Because of premise 6, a functioning premise having been derived from a premise DOES NOT constitute a reduction in the odds the original premise is false.

8. Because of premise 4, when man encounters a premise as described in premise 2, man will take the most dangerous of false premises and will end up adjusting it, causing premise 3 to take effect. In turn this lengthens the lifespan of the false premise more securely rooting premise 4 and ensuring that this cycle will repeat.

9. Occum's razor is a false premise. Since the CORRECT answer to a problem can be more complex than a false one, and since there is more than one answer which can resolve a given set of evidence, it's perfectly plausible, in fact likely that Occum's razor is regularly used to cut away correct answers. Further premise 4 increases this likelihood.

10. These premises taken together present an unresolvable situation.

Due to human flaws, and flaws in our standard methods, we've unintentionally implemented a hack. That allows us to base further progress on false premises which emulate the function of correct premises. While this certainly results in accelerated tangible progress, ultimately this string of false premises MUST FAIL to be extendable and we will achieve the limits we can progress to using this system.

Although we can't resolve this problem via any solution I am able to think of. What we can is patch the human flaw in the system. We can do this by submitting the same findings to peer review we do now, but doing so again at intervals in the future, assuring as much material is re-reviewed in light of new e

pinball, schimball

[BortQ]

Bah! This is just LiveScience trying to scam us to keep on feeding in the quarters.

If this is true.

[Murphy Murph]

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.

[mopomi]

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) 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 (data) is "bad". That is, the solution is non-unique and without some other a priori knowledge, we wouldn't be able to distinguish different forward models.

The longest ST episode title

[Scrameustache]

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. : )

East L.

[Tablizer]

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.