Freethought & Rationalism Archive

Dr.GH · 10-02-2002, 11:04 AM

Dream LLama said,
"Effectively, they're refuting their own claims that God's design of the universe was
'perfect'."

That is a really fun observation. I plan to shamelessly use it at the first opportunity.

Bialar Crais · 10-02-2002, 12:07 PM

Quote:

Originally posted by zzang:
Nice double standard. It's ok for evolutionists to extrapolate micro-evolution backwards in time but the second a Bible believe does the same thing with respect to the Earth's magnetic field he is labeled a fool and said to be wrong.

There's a difference you know. There's nothing wrong with extrapolating as long as one tries to find data to either confirm, or deny, the extrapolation. This is done in every field of science, including evolution.

Cretinist on the other hand, extrapolates far beyond what the data supports, and clings to their position no matter how many time their errors are pointed out for them. No matter how much data is found that directly contradict their extrapolation, they a never wrong.

See the difference? See which is scientific and not?

As someone pointed out, if all the data you got access to is your backyard, extraploating that the Earth is flat is not really bad science. But when data arrives to show that the Earth is spheroid, and one still cling to a flat earth due to the flatness of your backyard, then you're out of line.

ps418 · 10-02-2002, 01:12 PM

From my perspective, JonF's criticism is the most direct and devastating: the net decay of the earth's magnetic field over time is not supported by paleomagnetic evidence. If the GMF was decaying at the rate supposed by YEC's (half life of ~1500 yrs), then the flood-era rocks should reflect a field several times as strong, and the "creation rocks" should reflect a field even stronger.

In reality, sedimentary and igneous paleomagnetic data do not support such a long-term decay in the intensity of the field. 'Paleomagnetometers' in Archean and Proterozoic rocks indicate field strength no greater than that of today.

Here are some abstracts from a previous post:

Ikuro Sumita, Tadahiro Hatakeyama, Arata Yoshihara and Yozo Hamano, Paleomagnetism of late Archean rocks of Hamersley basin, Western Australia and the paleointensity at early Proterozoic, Physics of the Earth and Planetary Interiors 128 (1-4) (2001) pp. 223-241

Quote:

We report the results of paleomagnetic and rock magnetic measurements of late Archean rocks from Hamersley basin, Western Australia, and the paleointensity determination for early Proterozoic. Basalts and banded iron formations have two to four components of remanent magnetization, and have consistent directions for different localities, indicative of geomagnetic origin. Rock magnetic measurements of basalts reveal that the main magnetic mineral is a fine-grained magnetite present in ~10 ppm in mass, which do not alter when heated up to its blocking temperature. We interpret the stable component up to ~390 �C as the post-tilting thermal overprint from uplift at 2.0 Ga, and the higher temperature component as the pre-tilting thermoviscous remanence during burial metamorphism. From the Thellier type paleointensity experiments using the thermal overprint component, we obtain a mean virtual dipole moment (VDM) estimate of (1.8�3.6)�1022 A m2. This suggests that early Proterozoic was characterized by a 1 weak geomagnetic field of less than one-half of the present.

Arata Yoshihara and Yozo Hamano, Intensity of the Earth's magnetic field in late Archean obtained from diabase dikes of the Slave Province, Canada, Physics of the Earth and Planetary Interiors 117 (1-4) (2000) pp. 295-307

Quote:

The geomagnetic field intensity in Late Archean times is evaluated from Archean diabase dikes intruded into the Yellowknife greenstone belt of the Slave Province, N.W.T., Canada. The dike set used is referred to as the 8a dikes, and their age is bracketed between 2620 and 2642 Ma by crosscutting relationships between the 8a dikes and adjacent granitic rocks dated by U�Pb method. Paleomagnetic directional data after thermal demagnetization (ThD) and results of some field tests suggest that the characteristic remanent magnetizations (ChRM) of the dikes have been acquired at ca. 2.6 Ga. Several rock magnetic studies indicate that the dike samples are suitable for paleointensity determinations. Thelliers' method with consistency checks was used for the paleointensity determinations, and two of the 8a dikes yielded the mean paleointensities of 30.9�1.1 and 43.9�1.2 T, respectively. The corresponding virtual dipole moments (VDM) of (6.3�0.2)�1022 A m2 and (9.0�0.2)�1022 A m2 are similar to the present day value, suggesting that, in the Earth's core, the dynamo process of comparable activity to that of the present day has already existed at ca. 2.6 Ga.

10-02-2002, 07:33 PM

Quote:

Originally posted by Philosoft:


You have to be joking. Did you read any of the fine articles linked to just above?

Yep, and they still don't explain how the reversal of the Earth's magnetic field somehow resets its strength.

10-02-2002, 07:38 PM

Quote:

Originally posted by Wyz_sub10:


Maybe because the evolutionary process leaves a wide breadth of evidence along the way. No biologist or paleontologist or embyologist looks solely at the present and works backwards.

Sure, that is if you assume evolution happens, anything will be evidence for it.

Quote:

What is often done with the magnetic field decay argument is to take only *some* of the information (selected information, purposely ignoring the rest) and extrapolate that backward *in direct opposition to evidence* to produce an argument that, by the way, has no bearing whatsoever on evolution.

Even as a kid, I remember hearing how the magnetic fields reversed at times. Anybody truly interested in investigating the decay argument as a proof of the world's young age would realize that it is hollow.

Seeing as how the reversal has never been observed there is no way to know if the strength of the field is magically reset when it happens. And if you think this has nothing to do with evolution then don't give the argument that "evolution takes millions of years" when someone asks to see it.

Quote:

It's obvious you haven't read any of the articles linked above, and it is even more obvious that you don't care to.

If you think there is a "double-standard" at work here your logic is deeply lacking beyond your inability to comprehend basic science.

[ October 02, 2002: Message edited by: Wyz_sub10 ]

Yea, yea, yea, same old insults. Next time respond with a bit more substance.

Kevin Dorner · 10-02-2002, 07:57 PM

Quote:

Originally posted by zzang:
Seeing as how the reversal has never been observed...

<a href="http://pubs.usgs.gov/publications/text/stripes.html" target="_blank">The Atlantic seafloor observed it well enough.</a>.

The article I referenced is a laypersons' article. <a href="http://www.geocities.com/earthhistory/CT.htm" target="_blank">ps418's article</a> is a bit more advanced.

[ October 02, 2002: Message edited by: Kevin Dorner ]

Jesus Tap-Dancin' Christ · 10-02-2002, 08:36 PM

Quote:

Originally posted by zzang:


Yep, and they still don't explain how the reversal of the Earth's magnetic field somehow resets its strength.

It doesn't reset--it simply fluctuates from strong to weak by itself, sort of like an AC circuit. Look at the voltage across a power outlet in your house, and then look only at a small portion. You'll see that it appears to decay (or grow) exponentially. Look at the whole cylce, and you see that it simply fluctuates sinusoidally.

An analogy, but by no means a proof.

Jesus Tap-Dancin' Christ · 10-02-2002, 08:38 PM

Quote:

Originally posted by zzang:


Yea, yea, yea, same old insults. Next time respond with a bit more substance.

Would a semitrailer be enough substance, or do you need a barge?

10-02-2002, 08:55 PM

Quote:

Originally posted by Kevin Dorner:


<a href="http://pubs.usgs.gov/publications/text/stripes.html" target="_blank">The Atlantic seafloor observed it well enough.</a>.

The article I referenced is a laypersons' article. <a href="http://www.geocities.com/earthhistory/CT.htm" target="_blank">ps418's article</a> is a bit more advanced.

[ October 02, 2002: Message edited by: Kevin Dorner ]

Uhm, I'm not denying that the Earth's magnetic field has reversed in the past, the rocks clearly indicate that it has. I'm just saying we have never experienced a reversal and measured the strength of the field afterwards.

Doubting Didymus · 10-02-2002, 10:29 PM

Quote:

Originally posted by zzang:


Uhm, I'm not denying that the Earth's magnetic field has reversed in the past, the rocks clearly indicate that it has. I'm just saying we have never experienced a reversal and measured the strength of the field afterwards.

So whats the problem? You admit that the field has reversed in the past many times, as indicated by the evidence from geology. Therefore, it is not possible to extrapolate the field directly backwards in time to determine an age of the earth.

Simple, right?

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10-02-2002, 11:04 AM	#21
Dr.GH Veteran Member Join Date: Jul 2001 Location: Dana Point, Ca, USA Posts: 2,115	Dream LLama said, "Effectively, they're refuting their own claims that God's design of the universe was 'perfect'." That is a really fun observation. I plan to shamelessly use it at the first opportunity.

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