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Wednesday, April 23, 2014

More on Mercury’s Magnetic Field

Posted by jlwile on August 17, 2012

Mercury's magnetic field and how it interacts with the solar wind.
(Image courtesy of Windows to the Universe, click for details.)

One of the many scientific successes of young-earth creationism involves planetary magnetic fields. In 1984, Dr. Russell Humphreys produced a model of planetary magnetic fields that not only explained the data that were available at the time, but it also made several predictions.1 Over the years, many of those predictions have been borne out by the data (see here and here, for example). Compare this to the old-earth theory, which continues to struggle in accommodating the data that we already know (see here and here, for example).

Not content to rest on his laurels, Dr. Humphreys has continued to use his successful model to make more predictions. One of his recent predictions involved what MESSENGER (the latest unmanned spacecraft to visit Mercury) would learn when it measured Mercury’s magnetic field. The last spacecraft to visit Mercury was Mariner 10 back in 1974-1975, and based on some assumptions, it was able to measure Mercury’s magnetic field. Since that measurement was made more than 35 years ago, and since the young-earth model predicts that all planetary magnetic fields should decay fairly rapidly, Humphreys used his young-earth model to predict that Mercury’s magnetic field should have decayed by 4-6 percent since Mariner 10’s previous measurement. By contrast, the old-earth model predicted no measurable change.

Nearly five months ago, I wrote about the scientific paper that had been written regarding MESSENGER’s measurement. The main conclusion from the paper was that the shape of Mercury’s magnetic field is completely unlike what was assumed in the Mariner 10 measurement. As a result, I concluded that the new measurement could not be compared to the old one. That, of course, was a disappointing conclusion, since I was very interested in finding if the young-earth planetary magnetic field model was successful in yet another one of its predictions.

Interestingly enough, the first comment on the post suggested that the old Mariner 10 data should be reanalyzed now that we know the shape of Mercury’s magnetic field. That way, a proper comparison of the two measurements could be made. At the time, I suggested that the raw data probably still existed, but it might be hard to retrieve because of the changes that had taken place in computer technology. As a result, I wasn’t sure whether or not such a reanalysis could be done.

Well, even though a reanalysis of the raw data hasn’t been done, Dr. Humphreys has done the next best thing, and it does seem that the data at least partially confirm his prediction.

Dr. Humphreys does not have access to the raw Mariner 10 data. However, like all of us, he does have access to the original paper that reported the result.2 In order to make a somewhat reasonable comparison, he found the maximum magnetic field strength measured by Mariner 10 in 1975 and noted the latitude of Mariner 10 and its distance from Mercury at closest approach. In other words, he found Mariner 10′s maximum value and the perspective it had when it probably made that measurement. He then looked at the MESSENGER paper and determined the maximum value that MESSENGER had measured as well as its latitude and distance from Mercury when that measurement was made. In other words, he also found MESSENGER’S maximum value and the perspective it had when it made that measurement.

He then used the shape of the magnetic field as determined by MESSENGER to determine what MESSENGER would have seen if it been at the same latitude and distance from Mercury as Mariner 10 had been. In other words, he used the shape of the magnetic field as determined by MESSENGER to “change MESSENGER’s perspective” to the same perspective that Mariner 10 had. When he did that, he found that Mariner 10′s measurement was 7.8% +/- 0.8% higher than what MESSENGER would have measured had it matched Mariner 10′s flight pattern.3

Now admittedly, this comparison is far from perfect. Rather than looking at the raw data, Dr. Humphreys was forced to read from graphs and make certain assumptions. For example, he had to assume that Mariner 10′s maximum measurement was made at its closest approach. He also had to assume that Mercury’s magnetic field shape had not changed significantly in more than 35 years. Nevertheless, given what is available, it is the best that can be done right now. Based on that, then, Mercury’s magnetic field has declined since 1975.

Now please understand that this is only a partial confirmation of the young-earth prediction. The decline is more than what the young-earth model predicted, which was 4%-6%. Dr. Humphreys suggests some possibilities to explain this discrepancy, including the idea that radioactive isotopes could be heating Mercury’s core, making its resistance higher and thus reducing the magnetic field more rapidly than his model suggests.

Personally, I think that there is enough error associated with this type of analysis that his reported error of 0.8% is overly optimistic. Thus, the decline might be consistent with his prediction, or it might be significantly greater than his prediction. At the same time, however, I don’t think there is enough error to make the decline equal to zero, which was the prediction of the old-earth model. Thus, while these data are not a complete confirmation of the young-earth prediction, they do indicate that the young-earth model is in better agreement with the measurements than the old-earth model.

I would like to make one other point. The young-earth model has the magnetic field originating so that it is centered on the planet’s core. However, MESSENGER’S measurement shows that the magnetic field is offset north of that point. Thus, the young-earth model must come up with a reason for this offset. Humphreys mentions this in his paper, and he suggests that perhaps a difference in the electrical resistance between Mercury’s inner core and outer core could explain how the magnetic field came to be offset over time. I would have to see more detail in order to understand how that would work, so at this point, I would chalk the offset of the field up as a problem for the young-earth model.

I do think that, on balance, Humphreys has shown that his young-earth model is at least more consistent with MESSENGER’s measurement than is the old-earth model. As a result, I would say that MESSENGER’s data can be counted as a partial victory of the young-earth model over the old-earth model. Hopefully, as time goes on, more data will allow us to determine exactly how much of a victory it is.

REFERENCES

1. D. Russell Humphreys, “The Creation of Planetary Magnetic Fields,” Creation Research Society Quarterly, 21, 1984 (available online).
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2. Ness, N.F., “The Magnetic Field of Mercury,” Physics of the Earth and Planetary Interiors, 20:209-217, 1979.
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3. D. Russell Humphreys, “Mercury’s Magnetic Field is Fading Fast – Latest Spacecraft Data Confirm Evidence for a Young Solar System,” Journal of Creation, 26(2):4-6, 2012.
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Comments

14 Responses to “More on Mercury’s Magnetic Field”
  1. Sean says:

    I’d be curious as to the solar activity at the time of both probes. It seems to me that could impact the shape of the magnetic field pretty severely — and unless that was accounted for the comparison is moot anyways (this is just a layman’s guess).

    Something like what is described at: http://www.nasa.gov/mission_pages/sunearth/news/News030712-X5-4.html for solar flares and Earth’s magnetic field

  2. WSH says:

    Now this is exciting! I hope a full reanalysis of the original data will be done now as these results are so intriguing. I do not think OECS will find what Dr. Humphreys did very reliable without the support of solid data and not just guesstimates from a perspective change, as interesting as the results might be. It’s a pity there isn’t more funding in this sort of research.

  3. jlwile says:

    Sean, that’s a lot of where Humphreys’s error comes from. According to the MESSENGER paper, the sun contributes as much as 20% to the field at lower latitudes and higher altitudes. Based on what is known about how the sun’s activity changed over the timeframe involved as well as the latitude and altitude used, Humphreys estimated how much the sun’s activity could factor into the change. As I said, it might be larger, but there simply isn’t enough there to make the error as much as the change itself.

  4. jlwile says:

    I agree, WSH!

  5. Kevin N says:

    We quite simply do not know enough about Mercury’s geomagnetic field and its history to state that “Mercury’s magnetic field is fading fast” as Humphrey states in the title of his August 2012 Journal of Creation article.

    Jay, you and I have gone back and forth before about geomagnetic fields before (http://blog.drwile.com/?p=2670) so there is no need to repeat all that. I’ll summarize by saying that there are two basic problems with YEC geomagnetic models (I’m thinking specifically of how they apply to Earth). The first is that they don’t fit the geomagnetic history of Earth, with long periods of relatively stable geomagnetism punctuated by relatively quick reversals. A vast majority of volcanic rocks are non-transitional; they have either normal or reversed magnetic polarity. If Earth’s magnetic field was fluctuating rapidly during the flood, most volcanic rocks should record a changing magnetic field, and they quite simply don’t.

    The second problem is trying to use a cyclical process—a fluctuating magnetic field—to determine the age of anything. To extrapolate a 200-year record of magnetic intensity measurements backwards in history to determine the age of the Earth would be a bit like standing on a beach and observing sea level rising. If it rose one foot per hour during my observation period, I would be able to use YEC geomagnetic reasoning to prove that the ocean couldn’t be any older than about 35,000 hours, or about four years. The problem with this reasoning should be obvious, as it ignores the cyclical nature of tides.

  6. jlwile says:

    Thanks for your comment, Kevin. Actually, all the available data point to the fact that Mercury’s magnetic field is fading fast. Not only does Humphreys’s analysis indicate that Mariner 10 measured a stronger magnetic field just over 35 years ago, but also the magnetization of Mercury’s crust indicates that its field was stronger in the past (and opposite in polarity).

    The fact that the vast majority of volcanic rocks are non-transitional is a problem for the old-earth theory, not the young-earth theory. In the old-earth theory, polarity reversals are slow. As a result, lava flows would be very likely to record transitions. In the young-earth model, polarity reversals are rapid. As a result, you would not expect many (if any) transitions to be recorded in igneous rock. Thus, as is the case with other aspects of the data related to magnetic fields, the young-earth model is in better agreement with the data than the old-earth model.

    You are assuming that planetary magnetic fields are cyclic because that’s what the old-earth model says. However, the data indicate that they are not cyclic. Earth’s magnetic field is decaying. The moon’s magnetic field has decayed away, as has the planetary magnetic field on Mars. In addition, all the data about Mercury indicate a magnetic field that is fading fast. Thus, the data don’t indicate planetary magnetic fields are cyclic. The data indicate that planetary magnetic fields shift polarity rapidly from time to time and decay away.

    I am not sure why you bring up extrapolating earth’s magnetic field record as we have it today. No one is doing that. The young-earth model starts from first principles and mathematically derives an equation for earth’s planetary magnetic field. Now…the derived equation fits the measured data quite nicely, but there is no extrapolation going on. Besides, if you want to talk about absurd extrapolations, that’s where old-earthers are king. After all, they take about 100 years’ worth of observations of radioactivity and then extrapolate over billions of years. Now that’s really nonsensical extrapolation!

  7. Kevin N says:

    Jay,

    Unless volcanic rocks cooled almost instantaneously during the flood—in which case they should all be obsidian rather than having the more typical volcanic textures of rhyolite, andesite, and basalt—they should all show signs of ongoing geomagnetic reversals. In the young-Earth model, one has to compress roughly 200 magnetic reversals into the flood year, meaning that there would be a reversal every one or two days on average. The fact is that the magnetic mineral alignments of virtually all volcanic rocks indicate that they were crystallized during times of geomagnetic stability. In the YEC flood geology hypothesis, most lava would have had to have been extruded and completely crystallized conveniently in these little one-day periods of either normal or reversed polarity.

    I am not “assuming that planetary magnetic fields are cyclic because that’s what the old-earth model says,” but stating that the Earth’s magnetic field goes through cycles of reversed and normal polarity because that is what we observe in the rock record. It is not a sine-wave sort of cycle in either intensity or periodicity, but a cycle nontheless: Normal-reversed-normal-reversed-normal-reversed…. There is no evidence whatsoever that Earth’s magnetic field is decaying; that was the whole point of what I wrote about trying to determine the age of the oceans based on a one-hour observation of tides on the seashore. In the past 200 years we see but a sliver of a longer-duration cycle. And again, the evidence from the rocks is that this is a cycle, not an exponential-type decay.

    The same thing seems to be going on for Mercury. Even though its magnetic field is quite a bit weaker than Earth’s, it too shows evidence of being able to reverse in polarity. And if magnetic polarities can reverse, it is rather absurd to think that a short-term trend in intensity can be used to say anything about about the ages of those fields.

  8. D. Perrine says:

    Now that an interesting comparison has been made, hopefully the extra effort will be put forth to retrieve the original data in raw form. I am still hoping for this result, however unlikely it may be.

  9. jlwile says:

    Thanks for your reply, Kevin. There is no need for lava to cool almost instantaneously during the Flood. As you very well demonstrate, the magnetic reversals in a YEC view were very fast, especially compared to the time it takes lava to cool. Thus, in a young-earth view, you would not expect lava to solidify in the middle of a reversal. So in the YEC view, you would not expect to see transitions preserved in igneous rock. What you would expect is to see rapid reversals preserved in the rock, and that’s exactly what you do see!

    As I mentioned previously, you would expect transitions to be preserved in and old-earth view, however, since in that view, the reversals are slow compared to the time it takes lava to cool. Thus, as I pointed out before, a lack of transitions is a serious problem for the old-earth view, and it is quite consistent with the young-earth view. In addition, the rapid reversals that are preserved in igneous rock are also consistent with the young-earth view and wholly inconsistent with the old-earth view.

    You are, indeed, assuming that magnetic fields are cyclic, because that’s not what the data show. All measurements of the earth’s magnetic field shows that it is decaying. In addition, the moon’s magnetic field has decayed away, as has the planetary magnetic field of Mars. In addition, Mercury’s magnetic field is fading fast. Thus, all the available data indicate that magnetic fields decay. There are no data that indicate the fields are cyclic. The two things the data show are (1) planetary magnetic fields decay and (2) they reverse polarity from time to time. Once again, this is 100% consistent with the YEC view, but #1 is wholly inconsistent with the old-earth view.

    Please note that as I explained before, there is no extrapolation going on in the YEC view. The only thing going on is an honest evaluation of the data. The data are very consistent with the young-earth view and very inconsistent with the old-earth view. The absurdities rest in the old-earth view, because the old-earth view requires scientifically-irresponsible extrapolations and a denial of the data that clearly show planetary magnetic fields decay.

  10. jlwile says:

    I agree, D. Perrine. NASA should make the raw data available so a more detailed analysis can be done.

  11. Kevin N says:

    Jay,

    I think that somehow we are talking past one another. I cannot understand your reasoning on this one.

    You say that in the YEC view, one would not expect to see geomagnetic transitions preserved in the rock record. Why not? If the flood was characterized by reversals that occurred every few days, most lava flows should either contain a record of changing mineral alignment as the flow crystallized from the inside to the center, or perhaps simply a chaotic or random distribution of mineral alignments. You should not see thick flows that are strictly normal or reversed; all but the smallest flows would take long enough to crystallize to record a reversal or even multiple reversals.

    The lava flows that preserve changing paleomagnetism (http://blog.drwile.com/?p=2670) are very rare, which is what one would expect if there were hundreds of thousands or millions of years of stability in between brief periods of flux as the geomagnetic polarity reversed. If there were a million years of one polarity and a thousand years of flux, one would expect only 1/1000 of the lava flows to be extruded during a reversal. If reversals take a much shorter period of time as the Steens Mountain/Columbia River Basalt studies have suggested, then the fraction would be even smaller.

    The field data is very consistent with the old Earth view, and entirely inconsistent with the YEC view.

  12. jlwile says:

    Kevin, I agree that we must be talking past one another. Perhaps the problem is that you are using your old-earth assumptions to try to imagine what to expect in a young-earth framework. Obviously, that doesn’t work very well. In the young-earth view, you don’t have smooth transitions in magnetic field reversals. The polarity shifts are catastrophic. Thus, the shifts occur quickly compared to the time frame over which lava cools. As a result, you would not expect to see many preserved transitions.

    Also, you keep saying that the poles reversed every “few days” in the young-earth model, but that is not true. Using the old-earth interpretation of the geological column, there are about 200 magnetic reversals. However, in the young-earth view of the geological column, many of those reversals are not independent events because the strata do not represent millions of years of deposition. As a result, the young-earth model has the field reversing every week or two, not every few days.

    Once again, however, the fact that there are any such preserved transitions is entirely inconsistent with the old-earth view, as the link you provide points out, because lava should cool significantly more quickly than the time over which the old-earth model produces pole reversals.

    No matter how you look at it, then, the field data on the earth’s magnetic field are utterly inconsistent with the old-earth model, but they strongly support the young-earth model.

  13. Kevin N says:

    Jay — I am not sure how YECs whittle hundreds of reversals down to 25-50 (every one to two weeks for a year). I couldn’t find an explanation of this on the internet or in my YEC library. It appears to be an arm wave.

    If the YEC reversals generally occurred too rapidly to be preserved in volcanic rocks, then those lava flows that were crystallizing when a reversal occurred should have a rind of one polarity and a core of the opposite polarity; and I don’t think this has been observed anywhere.

    Perhaps the reason we seem to be talking past one another isn’t that I am using old-Earth assumptions (I used to be a YEC so I can think like a YEC), but that you are failing to appreciate the complexity of both the rock record and the geomagnetic record.

  14. jlwile says:

    Kevin, your YEC library isn’t as complete as you think. Back in 1988, Humphreys produced a paper analyzing paleomagnetism and defending the idea that the earth’s magnetic field has reversed polarity [D. Russell Humphreys, "Has the Earth's Magnetic Field Ever Flipped?," CRSQ, 25(3), 1988]. In it, he discusses why he thinks there were 50 reversals in the past. Once again, despite your YEC background, you are thinking like an old-earther. When old-earthers find two igneous rock formations in different places that are “dated” as being millions of years apart, they see those formations as occurring separately. Young-earthers don’t. As a result, records of polarity reversals that old-earthers think occurred at separate times are not necessarily separate in the young-earth view.

    You say that any lava flow that was cooling during the time of a reversal should have a rind of one polarity and a core of the opposite polarity. However, for that to happen, the timing would have to be impeccable. I would not expect such timing to occur frequently, which is why we don’t see such things. However, by studying thin layers of lava, rapid reversals have been found. This is exactly what the young-earth model predicts, and it is completely inconsistent with the old-earth model. Thus, once again, the field data support the young-earth model and contradict the old-earth model.

    I freely admit that I am not an expert on the geomagnetic record. However, I also know that what old-earths call “complexity” is often an excuse for the fact that the data do not support their model. In fact, as this paper shows, the paleomagnetic record is very consistent with the young-earth model and quite inconsistent with the old-earth model.

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