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Friday, November 21, 2014

The Earliest Eyes Look Like Modern Ones

Posted by jlwile on July 22, 2011

A krill, with a magnified view of its eye. (Click for krill picture credit. Eye credit is at commons.wikimedia.org/wiki/File:Krilleyekils.jpg)

A recent article1 in the journal Nature reports on fossil eyes that were discovered in early Cambrian rock. Before I discuss the fossils themselves, I have to make it clear that these eyes are not like the eyes you and I have. You and I have simple eyes. This doesn’t mean they aren’t complex. It just means that each of our eyes has only one lens. In addition to people, many animals have simple eyes.

The fossils discussed in the article were of compound eyes, like the one shown in the picture above. Unlike simple eyes, compound eyes have many, many lenses. Each little “section” you see in the magnified view of the eye is a separate lens. Each lens focuses the light onto its own, separate light-sensitive tissue. For this reason, a compound eye can be thought of as a lot of tiny individual eyes, each of which is called an ommatidium (plural is ommatidia).

Now why would an animal want a compound eye? Well, it allows the animal to have a much wider view. Some insect compounds eyes, for example, allow the insect to see nearly everything around it – not only what is in front of it, but also what is above, below, and behind it.2 In addition, since the visual information is being processed by lots of little units rather than one big unit, a compound eye is much more efficient at developing images, making it sensitive to very fast motion.3 This allows the insect to travel at high speeds without running into things, and it allows the insect to see even the slightest motion from both predators and prey. These advantages do come at a cost, however. The visual acuity and resolution of a compound eye is not as good as that of a simple eye.4

The article reports on seven compound eye fossils that were found in Cambrian rock. According to scientifically-irresponsible dating techniques, these rocks are supposedly 515 million years old. Nevertheless, the fossil eyes are incredibly advanced.

First, each eye has over 3,000 ommatidia. This is the same as the number of ommatidia in today’s common housefly.5 Second, the ommatidia are not all the same size. Instead, they are smaller near the edges of the eye and larger in the middle. This forms a “bright spot” in the middle of the eye, and the images seen there have a higher acuity those seen by the edges of the eye. This allows the owner of the eye to choose what it wants to see with higher acuity and what it wants to see with higher sensitivity to motion.

One way scientists measure the advanced nature of a compound eye is to determine the ratio of sizes in the ommatidia of the bright zone compared to those at the edges of the eye. The larger the ratio, the better the eye is at giving the insect both sensitivity to motion and good visual acuity. According to the authors:

The ratio of lens diameters in the bright zone to lens diameters in the margin (~2.5:1) exceeds that found in other Cambrian arthropods (trilobites and cambropachycopids) and is comparable to that in many modern taxa such as dragonflies, which have ratios of 1.61-2.71:1.

In other words, these fossil eyes, which are supposedly 515 million years old, are comparable to the compound eyes found in living animals today. In fact, the authors make this very clear in their abstract:

The eyes are more complex than those known from contemporaneous trilobites and are as advanced as those of many living forms.

So these are incredibly advanced eyes. Nevertheless, according to evolutionists, they are among the oldest eyes ever found in the fossil record. As far as we can say right now, then, the fossil record goes from no eyes to incredibly complex eyes, with nothing in between. In addition, the oldest complex animals found in the fossil record are supposedly 635 million years old, and they have no eyes.6 So in a “mere” 120 million years (or less), animals without eyes had to give rise to animals with incredibly complex eyes.

But that’s not the end of the story. Supposedly, evolution produced these incredibly advanced eyes in a “mere” 120 million years (or less), but since then, there haven’t been any serious improvements to the compound eye. Instead, evolution has been stuck with a 515-million-year-old design because the magic of mutations and time just isn’t enough to produce any significant improvement.

Now of course the authors of the paper have no problem with this odd situation. Instead, they discuss how their results are consistent with the idea that the Cambrian Explosion (where all the basic body plans in the animal kingdom simply “exploded” onto the scene) was fueled by the development of good eyesight. After all, if such advanced eyes exist in Cambrian rock, then good eyesight was around back then. Thus, it might have fueled the explosion of evolution that supposedly took place in the Cambrian.

Of course, they fail to answer the most obvious question: “What fueled the evolution of these incredibly advanced eyes in such a short amount of time, and why aren’t there any fossils that show how it happened?” They don’t answer this question, of course, because there is no answer to it.

REFERENCES

1. Michael S. Y. Lee, et al., “Modern optics in exceptionally preserved eyes of Early Cambrian arthropods from Australia,” Nature 474:631-634, 2011.
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2. E. Bruce Goldstein, Encyclopedia of Perception, Volume 1, Sage Publications, Inc 2009, p. 55.
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3. Robert W. Matthews and Janice R. Matthews, Insect Behavoir, Springer 2009, p. 273
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4. Ibid, p. 272
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5. Michael F. Land, “Visual Acuity in Insects,” Annual Review of Entomology 42:147-177, 1997.
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6. Conway Morris, S., “Ediacaran-like fossils in Cambrian Burgess Shale–type faunas of North America”. Palaeontology, 36: 593–635, 1993,
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Comments

12 Responses to “The Earliest Eyes Look Like Modern Ones”
  1. Sandy says:

    It’s incredible. The more science discovers the more it proves the Bible is correct and the more the evolutionists deny it does. And then they keep adding to their “assumptions” – that whole mutations theory is totally bogus-but they had to come up with some kind of explanation, didn’t they?! It all just boggles the mind. Thank you, so much Dr. Jay, for presenting the FACTS as they stand. It all just makes one wonder how much longer “they” will continue on in denial. One must come to the conclusion that they are being influenced by forces other than logic.

  2. jlwile says:

    Thanks for your kind comment, Sandy. Some have stopped their denial, but others will continue. It just depends on who is willing to be persuaded by the evidence and who will cling to their unsupportable beliefs no matter what the data say!

  3. Paul Quinton says:

    I cannot understand why you who have a PhD in Nuclear Chemistry say, “According to scientifically-irresponsible dating techniques, these rocks are supposedly 515 million years old.” without (i) giving your own estimate of how old they might be or (ii) what magnitude of error we are looking at or (iii) if you accept that there are other, more reliable, techniques and if so, what they are.

    Added to this,you do not say how old you thinks the rocks are, neither do you give any evidence you might hold.

    On the question of eyes, could you explain why an organ, once sufficient for the purpose, should then “evolve” beyond necessity?

  4. jlwile says:

    Thanks for your comment, Paul. One of the most important things a scientist should do is rely on the data to form an opinion. If the data do not indicate something, the scientist should not try to form an opinion about it. Since I don’t see any scientifically-reliable way to date those rocks, it would be scientifically irresponsible of me to attempt to offer an age. However, I can offer an upper limit. Several lines of evidence indicate that the earth is on the order of 10,000 years old. Thus, I would say that these rocks are younger than that.

    I have certainly given evidence for the view that I hold. In fact, the words “scientifically-irresponsible” are linked to an article that specifically shows why such dating methods are scientifically irresponsible.

    In answer to your question, evolution specifically expects organs to continue to evolve “beyond necessity,” since environmental conditions are always changing. As a result, any new biological innovation that gives an advantage will end up being preserved by natural selection. Thus, necessity is not the issue in evolution – advantage is. Since there was obviously a lot of environmental change over the hundreds of millions of years between these eyes and modern eyes, you would expect at least some change in the eyes themselves.

  5. Paul Quinton says:

    Interesting, in the section to which you referred me, you say, “So if the nuclear reactions in the sun play by the same rules as those in the lab, there shouldn’t have been liquid water on the earth billions of years ago. Nevertheless, there was.”

    So there was water on earth billions of years ago. Do you suggest there were no rocks at that time? And how do you reconcile that with believing the earth is only ~10,000 years old?

    You cite magnetism, yet the fatal flaw in this argument is the assumption of a constant rate of decline. There is no reason to believe that the rate of change in the magnetic field a thousand years ago or ten thousand years ago was the same as observed in the last two centuries. On the contrary, there is abundant evidence that the strength of the earth’s magnetic field fluctuates up and down, and even repeatedly reverses. Therefore we would expect it to be often increasing or decreasing in strength at any given time.

    You cite the levels of Helium, “several studies have estimated that radioactive decay currently produces a helium flux of 2,000,000 atoms each second for every square centimeter of the surface of the earth.”

    You obviously recognise that there is atomic decay and that over the long term it is relatively regular and can be used for dating. I did ask you what you thought to be the level of magnitude of error of the “scientifically-irresponsible dating techniques”. You may have missed this, as you did not reply. However, in your He calculations, you seem to believe that decay can date objects.

    Could you explain?

  6. jlwile says:

    Paul, I think you misunderstood the point about the sun. According to those who believe in a billions-of-years-old earth, there had to be liquid water on the earth billions of years ago. However, if nuclear reactions in the sun play by the same rules as those in the lab, there shouldn’t have been. This indicates that those who believe in a billions-of-years-old earth are incorrect.

    There is no fatal flaw in the magnetism argument. Once again, I think you misunderstood the post. The young-earth model of planetary magnetic fields specifically does not assume a constant rate of decline. It assumes how the magnetic field was produced, and then it uses nothing but physics to predict how such a magnetic field would decline over time. It also includes the fact that the magnetic field has reversed. That model not only reproduces all observed data collected over 200 years, but it was able to predict data that hadn’t even been measured at the time. That provides strong evidence for the validity of the model. You are correct that according to the dynamo theory, you would expect the magnetic field to be often increasing or decreasing. However, the dynamo theory is at odds with most of the data related to planetary magnetic fields. I prefer to stick to the model that is consistent with the data.

    You say that I “obviously recognise that there is atomic decay and that over the long term it is relatively regular and can be used for dating.” However, that is quite false. In fact, the available evidence indicates that radioactive decay rates are not relatively regular. This is a conclusion I did not want to come to, but the data led me to it, kicking and screaming the entire way. Since radioactive decay rates are not regular, they cannot be used for dating, which explains why so many radioactive dates are in conflict with one another and the conventional dates of geology.

    As I thought I made clear from my first reply, the data indicate to me that the earth is on the order of 10,000 years old. Thus, that’s an upper limit on the age of the rocks. As a result, I think the order-of-magnitude of error in the dates given by this study is roughly a factor of 10^4.

  7. Paul Quinton says:

    You seem to have overlooked my question as to what order of magnitude you believe the the error in the means of measuring age by decay to be.

    You say “several studies have estimated that radioactive decay currently produces a helium flux of 2,000,000 atoms each second for every square centimeter of the surface of the earth.”

    and you say, “Assuming there was absolutely no helium in the atmosphere when the earth was created, at the current rates of helium production and escape, it would take less than 2 million years to get the amount of helium that we see in the atmosphere today.”

    Firstly, could you justify, other than as an assumption that there was catually no helium in the atmosphere at the start? I can find no evidence to say if this is right or wrong or a good estimate.

    Next, you are using radioactive decay to calculate how much helium there should be, and yet you do not accept decay as a reliable measure of time, do you see the problem?

    You refered me to “In fact, the available evidence indicates that radioactive decay rates are not relatively regular.” You have cited special circumstances and, even were this disrgarded, the maximum error is 300% – even this does not account for the difference between your 10,000 years and mainstream science saying 3.54 Billion years. You will also see that the actual error is likely to be far, far less than this.

    As far as Helium lost to space is concerned – would you have a look at these figures and see where they are, according to you, in error? They may well be, It is very late here.

    Potential energy of helium atom near the surface is
    P = -mgRe = -μ/Na gRe

    Exponential factor in Boltzmann distribution is
    exp(-P/kT) = exp(μ/Na gRe / kT) = exp(μ/(RT) gRe)

    Assuming T= 300 K we have
    μ/RT gRe = 0.004/(8.3 300) 9.8 6,370,000 = 100

    So once per exp(-100) ~ 10^-43 attempts at escaping helium atom manages to do so. Probability 10^-34 is very small, but it sharply depends on temperature. Throw in 1000K and you have p ~ 10^-13, which means rather quick escape.

    Conclusion:
    Planet Earth is unable to hold lighter gases, namely hydrogen H2, HD, D2, and helium He4 and He3.

  8. jlwile says:

    Paul, I have not overlooked your question. As I said in my previous reply to you, “As I thought I made clear from my first reply, the data indicate to me that the earth is on the order of 10,000 years old. Thus, that’s an upper limit on the age of the rocks. As a result, I think the order-of-magnitude of error in the dates given by this study is roughly a factor of 10^4.”

    I cannot justify the assumption that initially there was no helium in the atmosphere. However, I can tell you that since there can’t be a negative amount of helium in the atmosphere, the assumption of no initial helium ends up providing an upper limit to the age of the atmosphere. If there were initial helium in the atmosphere, the atmosphere would have to be even younger. Thus, the assumption of no initial helium in the atmosphere is simply giving the old earth hypothesis as much leeway as it can possibly have with respect to that variable.

    You ask, “you are using radioactive decay to calculate how much helium there should be, and yet you do not accept decay as a reliable measure of time, do you see the problem?” There is no problem, because the available evidence suggests that radioactive decay was faster in the past. This, once again, makes the atmosphere even younger. So by assuming that the decay rates have been the same, I am simply giving the old earth hypothesis as much leeway as possible with regard to the input variable. Even with such incredible leeway, however, the old earth hypothesis is invalidated by the data.

    I understand that you want to believe the data on variable radioactive decay rates are the result of “special circumstances,” but there is no evidence to indicate these are special circumstances. Indeed, the helium in zircon data (reference 5) deal with the decay of uranium, which is anything but special. It is the bedrock of many dating techniques. Even if the data are the result of special circumstances, the fact that they occur and cannot be explained indicate that we don’t know radioactive decay well enough to extrapolate about 100 years worth of observations over billions of years! Also, you need to read that post again, since you seem to think that the maximum error is 300%. The data in reference 5 show that the error is on the magnitude of a factor of 10^6.

    In answer to your question about helium dynamics, your equations assume that the thermal energy a gas molecule has on the surface of the earth determines whether or not it escapes. This is completely incorrect, as the molecule collides with other molecules as it rises, and since all those molecules are expanding adiabatically, the molecule loses thermal energy as it rises. This is, of course, why the temperature of the atmosphere decreases as you increase altitude (until you reach the ozone layer, which then switches the gradient due to its behavior as a greenhouse gas). If you want to understand the physics involved, I would encourage you to look at the original paper that discusses the issue (reference 1) and the follow-up papers (references 5-7). As they make clear, the earth does, indeed, hold on to the lighter gases when any kind of reasonable physical analysis is used.

  9. Paul Quinton says:

    You say, “As I thought I made clear from my first reply, the data indicate to me that the earth is on the order of 10,000 years old. As a result, I think the order-of-magnitude of error in the *dates* given by this study is roughly a factor of 10^4.”

    I think it is clear what you think the order-of-magnitude of error in the *dates* is. That is the order of magnitude between what mainstream science says is the age of the earth and what you say is the age of the earth.

    I’m sorry to press you on this but do I understand you to be saying that decay rates are in fact 10^4 greater than normally accepted and have been so over the last 10,000 years only?

    You say, “There is no problem, because the available evidence suggests that radioactive decay was faster in the past.” Could you say *how much faster* the decay was and point me to some peer reviewed research that would support this.

    You say, “Indeed, the helium in zircon data (reference 5) deal with the decay of uranium, which is anything but special.” Well, not all helium is in Zircon, so it must be a little special :) There is far more uranium outside of Zircon. Under normal circumstances, Uranium does not usually display this decay rate, does it? Why would you choose this particular measurement?

    For your theory to be viable, it seems to me that radioactivity must have been much faster in the past. I’m sure this isn’t a bare statement for you say, “Only extrapolate the data when the range over which the extrapolation occurs is SMALL compared to the range over which the data are measured.” However, as you see from your own graph, extrapolation at a point near a curve could be misleading. So how did you avoid a possible error of extrapolation and arrive at the high decay rate?

    You object to my maths and, quite possibly correctly, but you say, “…the temperature of the atmosphere decreases as you increase altitude until you reach the ozone layer.” when it reaches 1,500 °C. You seem reluctant to say that this is going to have an effect on He.

    You say, “The young-earth model of planetary magnetic fields […] reproduces all observed data collected over 200 years, but it was able to predict data that hadn’t even been measured at the time.” Would that theory also hold for 24.5billion years?

    Thank you for the time you are spending.

  10. jlwile says:

    My pleasure, Paul. I enjoy answering questions. You ask, “do I understand you to be saying that decay rates are in fact 10^4 greater than normally accepted and have been so over the last 10,000 years only?” No, that is not what I am saying. The work of Humphreys and others provides evidence for a one-time event in which radioactive decay rates were sped up drastically. That one-time event seems to have happened (according to the data collected by Humphreys and others) about 6,000 years ago.

    You ask “how much faster?” As discussed in the Humphreys article, it’s about a factor of 10^6. That article is, indeed, peer-reviewed. The entire book in which it was found was peer reviewed.

    I don’t think you understand the data from Humphreys, which is what we are talking about with uranium decaying in zircon. The zircon only allowed for the observable (an unusual buildup of helium). Thus, this is not a special case. It is simply a special way of observing the standard decay of uranium. It was used because zircon is rather porous to helium. Thus, you would expect little buildup of helium in zircons that hold uranium, as the alpha particles should escape the helium about as fast as they are produced. It turns out that zircons that hold uranium have a lot of helium buildup, which allowed the testing of the models discussed in the paper.

    You ask, “So how did you avoid a possible error of extrapolation and arrive at the high decay rate?” I am not sure that I did. I am simply looking at the evidence. The evidence might, indeed, be fooling me because of some effect like that. However, it is consistent with the fact that we know by direct measurement that radioactive decay rates can be variable. It is also consistent with the data that indicate a young earth. This makes me more inclined to believe the evidence.

    The change in the temperature gradient does, indeed, affect the He. That’s why I suggested that you look at the original articles, where a realistic model is used. The realistic model takes that (and many other things) into account to show that there is a problem with the atmosphere’s helium inventory.

    You ask if the young-earth model of planetary magnetic fields would hold for billions of years. I am not fond of extrapolating anything over that time period, as it is rather scientifically irresponsible. What the young-earth model of planetary magnetic fields does indicate, however, is that the earth’s magnetic field will not last for even tens of thousands of years, much less millions or billions of years.

  11. PaulQ says:

    You remark, “I don’t think you understand the data from Humphreys,”

    Is that the same Humphreys who said in Humphreys et al. (2003):

    “Samples 1 through 3 had helium retentions of 58, 27 and 17 percent.* The fact that these percentages are high confirms that a large amount of nuclear decay did indeed occur in the zircons. Other evidence strongly supports much nuclear decay having occurred in the past [Humphreys, 2000, p. 335-337]. We emphasize this point because many creationists have assumed that “old” radioisotopic ages are merely an artefact of analysis, not really indicating the occurrence of large amounts of nuclear decay. *But according to the measured amount of lead physically present in the zircons, approximately 1.5 billion years worth — at today’s rates of nuclear decay – occurred*.”?

    Page 21 gives the significant temperature/diffusion rate, thus explaining the varying rates of diffusion. This is significant when considering the sample site, as obviously the temperature would be cooler near the surface.

    I don’t think I have misunderstood much. I did take the time to look at the geology or the area from which the samples were taken – it is certainly unusual and about 1.5 billion years old.

    I assume you are familiar with Reiners, P.W., 2005, Zircon (U-Th)/He Thermochronometry, in Reiners, P.W. and Ehlers, T.A. (Eds.), Thermochronology, Reviews in Mineralogy and Geochemistry, v. 58?

    But you may ask, “Why would anyone take the helium rate of decay and not the Uranium? Why is one preferable?” Humphrey’s examination of Helium fails to predict the helium contents of other zircons found at different sites in Asia and North America. The zircons have clearly lost more helium than could be explained by a few thousand years of diffusion at low temperatures.

    I am grateful that you committed yourself to a decay rate, “You ask “how much faster?” As discussed in the Humphreys article, it’s about a factor of 10^6. That article is, indeed, peer-reviewed. The entire book in which it was found was peer reviewed.”

    Naturally, I am a little disappointed that those who reviewed it were taken solely from the ranks of those who believed in a young earth before they embarked on the review. You may concede that a danger here is that one might conclude this is judging in one’s own cause.

    Whereas this might be fine in many areas, extraordinary claims, (and you must admit that they are not mainstream) require extraordinary evidence and to be examined most critically.

    That aside, is there any reasonable explanation as to why, if those rates of decay are a million times higher than others suggest, (and they must have stayed at those high levels for some time) that the levels of radio-activity did not kill all around? I am assuming that you accept that there was mammalian life at that time. Please say if you do not.

    You obviously understand that your opinions are not of the usual sort and you say “However, it is consistent with the fact that we know by direct measurement that radioactive decay rates can be variable.”

    I don’t think anyone will disagree that they are slightly variability, but the question is “how variable?” a million times seems somewhat excessive doesn’t it?

    I’m sure you’re not purposely evading answering but, I asked if the young-earth model of planetary magnetic fields would hold for billions of years. You replied, “I am not fond of extrapolating anything over that time period,” which, of course does not answer the question. It is possible for it to be extrapolated. Indeed you then extrapolate:

    You say, “What the young-earth model of planetary magnetic fields does indicate, however, is that the earth’s magnetic field will not last for even tens of thousands of years, much less millions or billions of years.” That, of course, is the future, and not the past.

    So, what does it look like for say 24.5 billions of years in the past?

  12. jlwile says:

    Paul, I am sorry if you were offended by me telling you that it seems you don’t understand the Humphreys data. Unfortunately, your remarks indicate that you do not. While you do quote him correctly, you then say “Page 21 gives the significant temperature/diffusion rate, thus explaining the varying rates of diffusion. This is significant when considering the sample site, as obviously the temperature would be cooler near the surface.” However, the Humphreys study addresses this specifically. On page 61, he calculates what temperature would be necessary in order to make the data consistent with 1.5 billion years. The answer is -78 C. This is why he says:

    The amount of shift required means that to get the diffusion coefficients low enough, say on the order of 10-23 cm2/sec, to allow a billion-year time-scale, the temperature in the granodiorite would have to have been extremely low, about that of dry ice.

    Thus, there is no reasonable way to claim that the rocks are “certainly” about 1.5 billion years old!

    I am, indeed, familiar with Reiners, P.W., 2005, Zircon (U-Th)/He Thermochronometry, in Reiners, P.W. and Ehlers, T.A. (Eds.), Thermochronology, Reviews in Mineralogy and Geochemistry, v. 58. I also understand that it does not present a problem for Humphreys’s conclusions. In fact, Humphreys addresses this directly as well in his paper. He doesn’t address Reiners’s 2005 work, as it had not been published yet. However, he discusses his previous work:

    Our diffusion dating method in Section 9 differs entirely from the “He dating” of (U-Th)/He chronometry [Reiners, 2002]. Very crudely, the difference is this: (U-Th)/He chronometry divides the number of He atoms in a crystal by nuclear decay rate. Diffusion dating divides the number of He atoms lost from the crystal by the diffusion rate. Some practitioners of (U-Th)/He chronometry, in their unpublished comments about our work, have not yet understood this distinction.

    You also claim that ” Humphrey’s examination of Helium fails to predict the helium contents of other zircons found at different sites in Asia and North America.” In fact, that is not true. As explained above, (U-Th)/He chronometry does not measure what Humphreys measured. In fact, he sees Reiners’s data as supporting his view:

    As an encouragement to creationists considering such work, we offer the following opinion: high He retentions are probably the rule, not the exception. Otherwise the large amount of geoscience literature reporting great (U-Th)/He chronometry ages (Section 9) would not exist. That is because the method essentially divides the amount of He retained by today’s nuclear decay rate, so large retentions of He are necessary to get great ages. If their zircons had lost most of their He by diffusion, their dates would be in great disarray, and usually rather young. Because their zircons are often of similar size as ours [Reiners, 2002], the He loss rates will be similarly fast. That suggests young diffusion ages such as ours will turn out to be common.

    You say you are disappointed that the peer review done on Humphreys’s paper was done only by creationists. I understand your disappointment. I am similarly disappointed that evolutionary papers are only peer reviewed by other evolutionists. However, that seems to be the way things are done.

    I most certainly agree that extraordinary claims require critical thinking. That’s why I am willing to question a billions-of-years-old earth. It is truly extraordinary claim that we can use about 100 years of observations to determine that the earth is billions of years old! Thus, I try to think critically about such a claim, and as a result, I don’t see enough evidence to support it.

    You ask about why this sped up of radioactivity didn’t kill everything on earth. That is a very good question, and there is no current answer to that. However, there are people attempting to address that issue. This is the way real science works.

    I agree that the question is “how much” can (and did) radioactive decay rates change. However, I don’t find a factor of a million to be excessive at all. In fact, the Humphreys data indicate that this is exactly what happened. Also, even a small amount of change demonstrates how little we understand radioactivity, as our current understanding expects no change. This should give any responsible scientist pause in extrapolating the process over billions of years!

    I am sorry I misunderstood your question about extrapolating the young-earth model of planetary magnetic fields. I thought you were talking about the future, not the past. The model does not go back 24.5 billion years. It begins with the creation of the earth, and based on the numbers, that couldn’t have been more than several thousand years ago.

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