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Author Topic:   Are Uranium Halos the best evidence of (a) an old earth AND (b) constant physics?
Dr Adequate
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Message 136 of 140 (667819)
07-12-2012 1:18 PM


About Theories: Science And Pseudoscience
When Einstein came up with his theory about gravity, about the first thing he did was to check that if it was correct, planets would go round the sun in ellipses with the sun at one focus, the way that they are known to to.

This was because he wanted to make sure that his theory really did explain gravity and wasn't just a collection of words and equations with no relevance to reality. And he was able to do this because his theory had predictive power --- it said something about what reality should look like if Einstein was right, and so all he had to do was derive from his theory a prediction about planetary orbits and so see if it was really about reality or just about the imaginary physics of an imaginary reality that existed only in Einstein's head.

So, foreveryoung, if you want to claim to have a theory which explains gravity, you need to do something similar.

You could show that if your idea is right, planets would travel in ellipses; or that when I throw a stone, it'll travel in a parabola (modulo friction) or that a heavy object and a light one will be attracted to the Earth with forces proportional to their weights. Or you could try proving that if you're right, then an object I drop will fall down, towards the center of the Earth, and not up or sideways. That would be a start. Or you claim to be able to explain the speed of light. Splendid, calculate from your idea what the speed of light should be. If the answer you get is what the speed of light is measured to be, then we shall begin to think that we are in the presence of an undiscovered genius.

But you can't do any of that, because your idea has not yet attained even the status of a hypothesis. It doesn't have sufficient content that you, or I, or anyone, can derive predictions from it. In which case it fails to explain phenomena, 'cos of not predicting any.

This is the difference between pop-science physics and actual physics. When we have an actual scientific hypothesis, we can do something with it, and so it provides us with real understanding. When we have a pop-science explanation, all it does is give us the sensation of understanding some aspect of physics. But unless it relates in some way to an actual scientific theory, this sensation is false.


Replies to this message:
 Message 137 by NoNukes, posted 07-12-2012 10:09 PM Dr Adequate has not yet responded

  
NoNukes
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Posts: 10130
From: Central NC USA
Joined: 08-13-2010
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Message 137 of 140 (667864)
07-12-2012 10:09 PM
Reply to: Message 136 by Dr Adequate
07-12-2012 1:18 PM


Re: About Theories: Science And Pseudoscience
You could show that if your idea is right, planets would travel in ellipses; or that when I throw a stone, it'll travel in a parabola (modulo friction) or that a heavy object and a light one will be attracted to the Earth with forces proportional to their weights.

Just to expand on what Dr. A is saying, it is necessary that any new theory give results that match the old theory in places where the old theory is known to work. It is not fatal if some notions of the new theory involve a little handwaving, but it is fatal if those notions don't lead to a theory that matches the old theory in domains where the old theory is good.

It is also fatal if the notion cannot be used to make any calculations at all, but perhaps such a failure is only due to the lack of skill of the notioneer.

In addition, if the new theory is going to replace the old theory, then there need to be some observations where the new theory explains things that the old theory cannot. And despite the wishes of some, Biblical interpretations of Genesis are NOT scientific observations.

For both types of predictions, we need to be able to proceed from notion, no matter how hand-wavy to calculation in a rigorous way. It is not enough to say "light comes in quantized energies", but we must be able to show that such quantization requires a given result that matches a known observation. For example, when Plank postulated the energy of photons to be hf, he was able to mathematically produce a prediction of the spectrum for black bodies that matched reality extremely well.

Applying those principles to fy's notion that vacuum energy affects the speed of light or any other physical, a convincing argument would require:

1. A rigorous calculation showing that the notion leads to predictions known to be true.

2. A rigorous calculation showing that some known observation not predicted by current theory follows directly from the given notion.

Again the notion itself might involve some handwaving and plausibility based argument. I would suggest that something like the equivalence principle or invariance of physical laws would serve such a role in General Relativity. But Einstein's was able to proceed from those notions to accurately account for the orbit of Mercury including motions not modeled using Newtonian physics.

Fy has not yet done a convincing job of hand waving.

Splendid, calculate from your idea what the speed of light should be.

Alternatively, it would be okay to use the known speed of light as a constraint or boundary condition. But you'd still need to make some calculations that have the predictive power I oulined above. After making those calculations, and only after, we might take a look at what your notion leads to in domains that we cannot currently observe.

In which case it fails to explain phenomena, 'cos of not predicting any.

That's it in a nutshell. Exactly so.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison


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 Message 136 by Dr Adequate, posted 07-12-2012 1:18 PM Dr Adequate has not yet responded

    
RAZD
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From: the other end of the sidewalk
Joined: 03-14-2004
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(1)
Message 138 of 140 (823259)
11-08-2017 11:36 AM


Summary compilation of the topic information to date -- a few lines for Starman
A "uranium halos for dummies" condensed version.

Message 1 laid out the initial premise:

... from Dr Wiens:
http://www.asa3.org/ASA/resources/Wiens.html

quote:
13. "Radiation halos" in rocks prove that the Earth was young.

This refers to tiny halos of crystal damage surrounding spots where radioactive elements are concentrated in certain rocks. Halos thought to be from polonium, a short-lived element produced from the decay of uranium, have been found in some rocks. ...

At any rate, halos from uranium inclusions are far more common. Because of uranium's long half-lives, these halos take at least several hundred million years to form. Because of this, most people agree that halos provide compelling evidence for a very old Earth.


(bold added for empHASis, part deleted not about uranium halos)

The basic radiohalo principle is simple: radioactivity produces alpha decay, and the alpha particle have a certain energy (usually measured in million electron volts, MeV) based on the familiar e=mc² formula and the conservation of energy/mass (see ref):

M1 = M2 + mp + e/c²

Thus when you have isotopes decaying into other isotopes by alpha decay, the energy of the alpha particle is unique to that decay stage because of the unique before and after mass of the decaying isotope and the constant mass of the alpha particle.

This unique energy then determines how far (on average) an alpha particle will travel before it gets stopped and absorbed into the surrounding material (and causes the ring pattern to be visible) and the result is a halo or a number of halos around decaying inclusions that look like rings, but are actually spherical, and something like this:

The halos require more than one particle to form as each one only makes a point on the ring. Thus uranium, with it's long half-life, takes "several hundred million years to form."

Now the fun part: this is based on our knowledge of physics and the physical constants that tell us how things behave in the universe, so what happens if you have fast decay instead of old time?

... Alpha Decay, Alpha detectors and identification:

quote:
However, if the alpha has enough energy to surmount this barrier then it will regain that energy as electrostatic repulsion once it gets outside the range of the attractive strong nuclear force. One important consequence of this is that all alpha emissions have at least ~5 MeV energy. Furthermore, half-life is inversely related to decay energy.
(bold for empHASis)

Very simply put, if you change the decay rate, you change the decay energy, and the diameter of the halo changes.

There should be no characteristic uranium halos with the unique energy of uranium alpha decay from fast decay.

The existence of (common) uranium halos then is evidence that shows the physical constants have not changed while they were formed, and their formation in turn is evidence that the earth is old, at least several hundred million years old.

Message 3 adds information on the physical process for how the halos are made:

article abstract The nature of radiohaloes in biotite: Experimental studies and modeling:

quote:
... Radiohaloes in biotite resulted from the impact of 4He cores (α-particles) emitted from actinide-bearing inclusions. Monte Carlo simulations yielded α (238U, 235U, and 232Th series) penetration ranges in biotite between 12.5 and 37.3 μm, which are in reasonable agreement with the observed radii of radiohaloes in natural biotites. The coloration pattern of a radiohalo closely correlates with the calculated distribution pattern of point defects generated in displacive events. Calculated point defect densities in the range from < 10-5 to at most 10-2 dpa (displacements per lattice atom) suggest that there are only scattered point defects in a mainly preserved biotite lattice. ...
(bold for empHASis)

SO the ring would be caused by the alpha particle causing a "point defect" in the surrounding material, interrupting the normal light pattern

And it takes a lot of those single point impacts at the same decay energy distances from the core to accumulate over time into a visible halo.

See Message 3 for more complete quote of the abstract.

Message 5 presents some of the mechanics of alpha decay:

... article on the forces in a nucleus and how that affects decay:

The Strong Nuclear Force, Alpha Decay and Fission

quote:
Unlike the electric forces, whose strengths are given by the simple Coulomb force law, there is no simple formula for how the strong nuclear force depends on distance. Roughly speaking, it is effective over ranges of ~1 fm, but falls off extremely quickly at larger distances (much faster than 1/r2). Since the radius of a neutron or proton is about 1 fm, that means that when a bunch of neutrons and protons are packed together to form a nucleus, the strong nuclear force is effective only between neighbors.

In a very heavy nucleus, (c), a proton that finds itself near the edge has only a few neighbors close enough to attract it significantly via the strong nuclear force, but every other proton in the nucleus exerts a repulsive electrical force on it. If the nucleus is large enough, the total electrical repulsion may be sufficient to overcome the attraction of the strong force, and the nucleus may spit out a proton. Proton emission is fairly rare, however; a more common type of radioactive decay in heavy nuclei is alpha decay, shown in (d). The imbalance of the forces is similar, but the chunk that is ejected is an alpha particle (two protons and two neutrons) rather than a single proton.

It is also possible for the nucleus to split into two pieces of roughly equal size, (e), a process known as fission.


This is just background information ...

Message 7 adds to the mechanics of alpha decay and includes the inverse relationship of alpha particle energy to isotope half-life:

From Alpha Barrier Penetration

quote:
The energy of emitted alpha particles was a mystery to early investigators because it was evident that they did not have enough energy, according to classical physics, to escape the nucleus. Once an approximate size of the nucleus was obtained by Rutherford scattering, one could calculate the height of the Coulomb barrier at the radius of the nucleus. It was evident that this energy was several times higher than the observed alpha particle energies. There was also an incredible range of half lives for the alpha particle which could not be explained by anything in classical physics.

The resolution of this dilemma came with the realization that there was a finite probability that the alpha particle could penetrate the wall by quantum mechanical tunneling. Using tunneling, Gamow was able to calculate a dependence for the half-life as a function of alpha particle energy which was in agreement with experimental observations.


Why an alpha particle and not a proton?

Alpha Binding Energy

quote:
The nuclear binding energy of the alpha particle is extremely high, 28.3 MeV. It is an exceptionally stable collection of nucleons, and those heavier nuclei which can be viewed as collections of alpha particles (carbon-12, oxygen-16, etc.) are also exceptionally stable. This contrasts with a binding energy of only 8 MeV for helium-3, which forms an intermediate step in the proton-proton fusion cycle.

I envisage it as a pyramid with each particle in contact with the other, and therefore bound by the strong force.

Message 8 provides the crux of the process:

Alpha Tunneling Model

quote:

The illustration represents an attempt to model the alpha decay characteristics of polonium-212, which emits an 8.78 MeV alpha particle with a half-life of 0.3 microseconds. The Coulomb barrier faced by an alpha particle with this energy is about 26 MeV, so by classical physics it cannot escape at all. Quantum mechanical tunneling gives a small probability that the alpha can penetrate the barrier. To evaluate this probability, the alpha particle inside the nucleus is represented by a free-particle wavefunction subject to the nuclear potential. Inside the barrier, the solution to the Schrodinger equation becomes a decaying exponential. Calculating the ratio of the wavefunction outside the barrier and inside and squaring that ratio gives the probability of alpha emission.


Change the decay rate, and you change the energy of the alpha particle. Not a strict inverse relationship (exponential?)

Message 9 provides some formulas:

PHYS 490/891 - Winter 2007, 2.8 Alpha-Decay

quote:
Qα = Eb(Z, A) - Eα(Z - 2, A - 4) - Eα(2,4) .

Now the we can translate the above condition for the possibility of an α-decay to Qα > 0. Fig. 14 shows a diagram with Qα-values for β-stable nuclei. Positive values start to appear for A > 150.

While the energy range of alpha-decays observed in nature is relatively narrow (~ 2 - 12 MeV) the lifetimes span a range from 10 ns to more than 10^19 years. To better understand this behaviour we will investigate the mechanism of this decay a little closer.
...
So we find for the decay constant:

λ = wαvαe-G/2R

Message 82 adds more information:

http://www.talkorigins.org/indexcc/CF/CF210.html

quote:
# The half-lives of radioisotopes can be predicted from first principles through quantum mechanics. Any variation would have to come from changes to fundamental constants. According to the calculations that accurately predict half-lives, any change in fundamental constants would affect decay rates of different elements disproportionally, even when the elements decay by the same mechanism (Greenlees 2000; Krane 1987).

Which means that the radii of the different halos for the different daughter isotopes would change by different amounts - yet this is not observed in the Uranium halos .... and therefore Uranium halos are indeed evidence that the earth is very old.

Note that not only do we have fully formed uranium halos, but the halos for each different element in the decay change are at the same relative location to each other based on current alpha decay energies. When you look at the decay chain for 238U you see:

http://en.wikipedia.org/...y#Decay_chains_and_multiple_modes

quote:
An example is the natural decay chain of 238U which is as follows:
  • decays, through alpha-emission, with a half-life of 4.5 billion years to thorium-234
  • which decays, through beta-emission, with a half-life of 24 days to protactinium-234
  • which decays, through beta-emission, with a half-life of 1.2 minutes to uranium-234
  • which decays, through alpha-emission, with a half-life of 240 thousand years to thorium-230
  • which decays, through alpha-emission, with a half-life of 77 thousand years to radium-226 ...

And the top three alpha decay events all have half-lives well in excess of any young earth fantasy model, so all three would need to be altered by magic in such a way that they still provide the same halo diameter ...

Change the physics to affect one, and not only do you have the problem of this also changing the alpha particle energy (and hence the halo diameter for that isotope), so that you need an additional "correction" of the alpha energy, but you have the problem of changing the other isotope decay rates and alpha particle energies to a different degree, that must now all individually be "corrected" by further adjustments to the physics while not undoing the "corrections" already made .....

The evidence speaks for itself: the earth is old.

You need to invoke different magic alteration of the physical constants for each isotope to end up with the observed results, which are in agreement with the predictions from the calculations.

Now I am going to include Message 90 because the argument from Smooth Operator is similar to the argument from Starman:

Uranium halos are not evidence for an old Earth because they are based on two assumptions you don't know anything about. So let's take it step by step...

1.) Half life of U238.

1.) The claim that U238 half-life is 4.5 billion years. How do you know that? Where has this been shown to be true? You don't know that. You assume that. And since you don't know it, you don't know that it took 4.5 billion years to make ANY U238 halo.

This denial of reality is based on both a logical fallacy (argument from incredulity) and general logically false thinking. The astute reader will note that Smooth Operator did not provide any evidence of a different decay rate, he just employed the PRATT that because event X was not observed we can know nothing about event X.

Curiously, the claim that Uranium Halos are evidence of extreme age for the earth comes from a scientist who does in fact know a whole heck of a lot more about the physics involved than Smooth Operator has demonstrated (he can't even get the facts right):

http://www.asa3.org/ASA/resources/Wiens.html

quote:
At any rate, halos from uranium inclusions are far more common. Because of uranium's long half-lives, these halos take at least several hundred million years to form. Because of this, most people agree that halos provide compelling evidence for a very old Earth.

Not just the 238U half-life, but the half-life of several of the decay products as well.

Amusingly, one does not need to observe a radioactive material for the full length of the half-life in order to measure the decay rate, as the physics involved follows very predictable paths.

If Smooth Operator's claim were true we would not know the half-life of a single element with a half-life over 50 years, while curiously, the half-lives of almost all elements are known to a high degree of precision.

Not only do we have the initial information of decay curves to provide the slopes at the beginning of exponential curves actively defining the half-life for the elements, we have parent-daughter relationships that show that the proportions of elements found does in fact correlate with the measured half-lives.

Radioactive dating methods also correlate and confirm each other, even though they are derived from materials with different half-lives and therefore different proportions of the various elements at different ages.

One example of such correlations is found with the Oklo evidence.
http://oklo.curtin.edu.au/

Another example of this is the correlation of radiocarbon dating with both annual tree rings and with organic specimens from the varves in Lake Suigetsu, showing that 14C dating methods do in fact represent the age of the specimens, because we know their age by other means, means that are more accurate than 14C (due to atmospheric variations in 14C) and which can be used to correct for the atmospheric fluctuations in the past.
However, to more fully discuss radioactive decay and dating systems that are based on this concept we would prefer a system not subject to this kind of variation seen with 14C. We also need one that can be correlated over substantial time to validate the system.

Such an example is found in

http://water.usgs.gov/nrp/devils.html (8)

quote:
In 1997, the Devils Hole Thorium-230 dates were independently confirmed by non-USGS investigators using Protactinium-231.
(See Broecker, 1992; Ludwig, et al., 1992; Winograd, et al., 1997; and Edwards, et al., 1997.)

Corroborated by two independent radiometric methods. The oldest date in the data table is 567,700 years ago.

So what exactly do we have here? Water dripping down a cave wall, depositing calcite and various other minerals and impurities, elements that are soluble in water, including trace levels of radioactive isotopes of uranium. Material that gets deposited with the calcite formation as the water evaporates, forming layer after layer of similar deposits, each one trapping the material in their respective layers. The calcite forms a matrix that holds the impurities, minerals and trace elements in a position related to the time the calcite was deposited.

The calcite is deposited year by year, with the soluble elements being trapped as the water evaporates, and thus dating the layers radioactively by the measurement of the relative amounts of non-soluble elements that are derived by radioactive decay of soluble radioactive elements.

In this case two independent radioactive elements, Thorium and Protactinium.

http://www.asa3.org/ASA/resources/Wiens.html (9)

quote:
Two of the most frequently-used of these "uranium-series" systems are uranium-234 and thorium-230.

... The chemistry of uranium and thorium are such that they are in fact easily removed from each other. Uranium tends to stay dissolved in water, but thorium is insoluble in water. So a number of applications of the thorium-230 method are based on this chemical partition between uranium and thorium. ...
Comparison of uranium-234 ages with ages obtained by counting annual growth bands of corals proves that the technique is highly accurate when properly used (Edwards et al., Earth Planet. Sci. Lett. 90, 371, 1988). The method has also been used to date stalactites and stalagmites from caves, already mentioned in connection with long-term calibration of the radiocarbon method. In fact, tens of thousands of uranium-series dates have been performed on cave formations around the world.


http://www.ead.anl.gov/pub/doc/protactinium.pdf (5)

quote:
Protactinium-231 is a decay product of uranium-235 and is present at sites that processed uranium ores and associated wastes. This isotope decays by emitting an alpha particle with a half-life of 33,000 years to actinium-227, which has a half-life of 22 years and decays by emitting an alpha or beta particle.

The U-235 to Pa-231 decay is from a different series than the U-234 to Th-230 decay, so the two are independent of each other. Again, as the Devil's Hole calcite was deposited after being dissolved in water, the Pa-231 in the calcite could only come from the decay of the parent U-235, giving an accurate measurement of the age of the layers of calcite.

http://en.wikipedia.org/wiki/Exponential_decay (4)

quote:
A more intuitive characteristic of exponential decay for many people is the time required for the decaying quantity to fall to one half of its initial value. This time is called the half-life, and often denoted by the symbol t1/2. The half-life can be written in terms of the decay constant, or the mean lifetime, as:
t1/2 = ln2/λ = Tln2

When this expression is inserted for T in the exponential equation above, and ln2 is absorbed into the base, this equation becomes:
N(t) = N02-t/t1/2

Using the half-lives of thorium-230 (75,380 years) and protactinium-231 (32,760 years), we can now draw the exponential curves for these isotopes (with % on the y-axis and time in k-yrs on the x axis, thorium in blue and protactinium in red):

This means we have a series of data with three different pieces of information: calcite layer age by relative depth in the formation, and Thorium-230 content and Protactinium-231 content in each layer. We also note that Thorium-230 has a half-life of 75,380 years, while Protactinium-231 has a half-life of 32,760 years - less than half the half-life of Thorium-230. This means that layer by layer the ratio of Thorium-230 to Protactinium-231 is different:

   Age   THr=THf/THo PAr=PAf/PAo  THr/PAr
---------------------------------------------
75,380 0.5000 0.2029 2.46
150,760 0.2500 0.0412 6.07
226,140 0.1250 0.0084 14.96
301,520 0.0625 0.0017 36.86
376,900 0.0313 0.0003 90.82
452,280 0.0156 0.0001 223.77
527,660 0.0078 0.00001 551.350

So for these dates to be invalid there would have to be a mechanism that can layer by layer preferentially change the ratio of these two {elements\isotopes} within the solid calcite vein.

Rather than just wave his hands in denial, Smooth Operator -- or anyone else trying to deny this evidence -- would have to show some reasonable method to achieve these different ratios by some other system.

This validates radioactive decay rates for the 567,000 year duration of this evidence, and confirms the half-lives for each of these isotopes.

In other words, we can have a high degree of confidence in the measured decay rates of the various elements involved from the multiple sources of information and from the correlations of information that validate these rates.

2.) Halo itself.

2.) And the second assumption, which is even worse. Is the assumption that the U238 halo was produced by a constand decay rate. And then you turn and say that since it was constant decy, it had constant energy, thus a specific halo was formed that can only be produced by constant energy. That's circular logic. Since you don't know by what energy strength was that halo formed, you don't know if it was formed by constant decay, and of course constant energy. And you don't know that, because you never saw a U238 halo form, and what energy it took to form the said halo, that you never saw form in the first place.

Again, Smooth Operator is missing the vital element of this issue: the alpha decay energy needs to be constant for the halos to form, as the diameter of the halo for each different isotope in the decay series is fixed by the unique alpha decay energy for that isotope.

Nobody needs to observe the halo being formed to see that the result is due to the alpha decay energies being the same for each isotope in the series over a period of time long enough for all the alpha decay events to have occurred.

Due to the physics involved, decay energy, whether alpha or beta, is related to the half-life of the particular isotope. Each isotope that decays by alpha decay has a unique alpha decay energy specific to that kind of decay event. This physics also shows that if you change the decay rate that this results in change to the alpha energy.

Further the physics shows that any change to the basics of decay will affect different isotopes to different degrees, so the change to one isotope's alpha decay rate\energy will be different from the change to another isotope's alpha decay rate\energy.

Thus the problem that needs to be explained is how all these decay events actually occurred with the precise alpha energy to form the halos if the decay rates were different. Each isotope decay rate change needs to be "juggled" in a different degree to explain the evidence of the halos.

Saying that there is evidence of decay rate changes (even if true) and saying that there is evidence of alpha energy changes (also even if true) does not show how this is coordinated to produce the halo at the correct diameter.

One needs to complete an alternate explanation that fully explains all the evidence, not just denial of the explanation provided by physics, the halos, and an old age for the earth.

Smooth Operator has not done this. His premises are false, and therefore all his conclusions are invalid.

I have no interest in debating Smooth Operator further on this issue, until he can show how each precise alpha decay energy can be produce by some other method, and demonstrate that decay rates can be changed by factors of thousands while producing the same alpha decay energy. He can start another thread to do this.

and the final bit I want to include in this summary is from Message 99:

http://en.wikipedia.org/wiki/Gamow_factor

quote:
The Gamow Factor or Gamow-Sommerfeld Factor[1], named after its discoverer George Gamow, is a probability factor for two nuclear particles' chance of overcoming the Coulomb barrier in order to undergo nuclear reactions, for example in nuclear fusion. By classical physics, there is almost no possibility for protons to fuse by crossing each other's Coulomb barrier, but when George Gamow instead applied quantum mechanics to the problem, he found that there was a significant chance for the fusion due to tunneling.

This probability increases rapidly with increasing particle energy, but at a given temperature the probability of a particle having a high energy falls off rapidly, following the Maxwell-Boltzmann distribution. Gamow found that, taken together, these effects mean that for any given temperature, the particles that actually fuse are mostly in a (temperature-dependent) narrow range of energies known as the Gamow window.[2]


Oh look, I found this by googling gamow decay energy calculation

http://www.phy.uct.ac.za/courses/phy300w/np/ch1/node38.html

quote:
... (several formulas with undefined symbols, have fun) ...
The Geiger-Nutall equation is thus recovered. Note the extreme sensitivity of the decay constant on the energy in the above equation.

Change the decay rate and you change the energy of the decay particle.

and

(PDF) On the Effectiveness of Gamow's Method for Calculating Decay Rates

quote:
We examine Gamow's method for calculating the decay rate of a wave function initially located
within a potential well. Using elementary techniques, we examine a very simple, exactly solvable
model, in order to show why it is so reliable for calculating decay rates, in spite of its conceptual
problems. We also discuss the regime of validity of the exponential decay law.
... (lots of formulas with undefined symbols, have fun) ...

The decay rate is calculated from the decay energy.

There you have it -- a direct link between decay energy and the half-life of the isotopes.

Note that this is not a linear function, so doubling the decay rate results in different decay energies of the alpha particles from different isotopes and they don't have the same ratios one to the next as we observe with today's decay rates.

Link this with the large number of decay events needed to form a visible halo and it is clear that these constants have not changed during the formation of the uranium halos

Enjoy

Edited by RAZD, : .

Edited by RAZD, : .


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Replies to this message:
 Message 139 by RAZD, posted 11-10-2017 3:34 PM RAZD has responded

  
RAZD
Member
Posts: 19332
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.2


Message 139 of 140 (823477)
11-10-2017 3:34 PM
Reply to: Message 138 by RAZD
11-08-2017 11:36 AM


Cliff Notes
  1. The basic radiohalo principle is simple: radioactivity produces alpha decay, and the alpha particle have a certain energy (usually measured in million electron volts, MeV) based on the familiar e=mc² formula and the conservation of energy/mass (see ref):

    M1 = M2 + mp + e/c²

    Thus when you have an isotope decaying into another isotope by alpha decay, the energy of the alpha particle is consistent for that isotope decay and unique for that decay stage because of the unique before and after mass of the decaying isotope and the constant mass of the alpha particle.

    This consistent and unique energy then determines how far (on average) an alpha particle will travel before it gets stopped and absorbed into the surrounding material (which causes the ring pattern to be visible) and the result is a halo or a number of halos around decaying inclusions that look like rings, but are actually spherical, and something like this:

    The halos require many more than one particle to form as each particle only makes a single point on the ring. Thus uranium, with it's long half-life, takes "several hundred million years to form."

  2. From Alpha Barrier Penetration

    quote:
    The energy of emitted alpha particles was a mystery to early investigators because it was evident that they did not have enough energy, according to classical physics, to escape the nucleus. Once an approximate size of the nucleus was obtained by Rutherford scattering, one could calculate the height of the Coulomb barrier at the radius of the nucleus. It was evident that this energy was several times higher than the observed alpha particle energies. There was also an incredible range of half lives for the alpha particle which could not be explained by anything in classical physics.

    The resolution of this dilemma came with the realization that there was a finite probability that the alpha particle could penetrate the wall by quantum mechanical tunneling. Using tunneling, Gamow was able to calculate a dependence for the half-life as a function of alpha particle energy which was in agreement with experimental observations.


    This is a non-linear inverse relationship between half-life and alpha particle enegy.

  3. Alpha Tunneling Model

    quote:

    The illustration represents an attempt to model the alpha decay characteristics of polonium-212, which emits an 8.78 MeV alpha particle with a half-life of 0.3 microseconds. The Coulomb barrier faced by an alpha particle with this energy is about 26 MeV, so by classical physics it cannot escape at all. Quantum mechanical tunneling gives a small probability that the alpha can penetrate the barrier. To evaluate this probability, the alpha particle inside the nucleus is represented by a free-particle wavefunction subject to the nuclear potential. Inside the barrier, the solution to the Schrodinger equation becomes a decaying exponential. Calculating the ratio of the wavefunction outside the barrier and inside and squaring that ratio gives the probability of alpha emission.


    Change the decay rate, and you change the energy of the alpha particle. Again, it is not a linear inverse relationship, so changing physical constants to change the decay rate changes the rates for different isotopes to different degrees.

    Thus if you jigger the physics to make one ring at the proper distance but with fast decay the other rings will not be in the proper locations.

  4. (PDF) On the Effectiveness of Gamow's Method for Calculating Decay Rates

    quote:
    We examine Gamow's method for calculating the decay rate of a wave function initially located within a potential well. Using elementary techniques, we examine a very simple, exactly solvable model, in order to show why it is so reliable for calculating decay rates, in spite of its conceptual problems. We also discuss the regime of validity of the exponential decay law.
    ... (lots of formulas with undefined symbols, have fun) ...

    The decay rate is calculated from the decay energy, and these calculated values matche the empirically tested and derived values, so there you have it -- a direct link between decay energy and the half-life of the isotopes.

    Note again that this is not a linear function, so doubling the decay rate results in different decay energies of the alpha particles from all the different isotopes and they don't have the same ratios one to the next as we observe with today's decay rates. This means that any change is detectable.

  5. Note that not only do we have fully formed uranium halos, but the halos for each different element in the decay change are at the same relative location to each other based on current alpha decay energies. When you look at the decay chain for 238U you see:

    http://en.wikipedia.org/...y#Decay_chains_and_multiple_modes

    quote:
    An example is the natural decay chain of 238U which is as follows:
    • decays, through alpha-emission, with a half-life of 4.5 billion years to thorium-234
    • which decays, through beta-emission, with a half-life of 24 days to protactinium-234
    • which decays, through beta-emission, with a half-life of 1.2 minutes to uranium-234
    • which decays, through alpha-emission, with a half-life of 240 thousand years to thorium-230
    • which decays, through alpha-emission, with a half-life of 77 thousand years to radium-226 ...

    And the top three alpha decay events all have half-lives well in excess of any young earth fantasy model, so all three would need to be altered by magic in such a way that they still provide the same halo diameter ...

    Change the physics to affect one, and not only do you have the problem of this also changing the alpha particle energy (and hence the halo diameter for that isotope), so that you need an additional "correction" of the alpha energy, but you have the problem of changing the other isotope decay rates and alpha particle energies to a different degree, that must now all individually be "corrected" by further adjustments to the physics while not undoing the "corrections" already made .....

The evidence speaks for itself: the earth is old.

Enjoy


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This message is a reply to:
 Message 138 by RAZD, posted 11-08-2017 11:36 AM RAZD has responded

Replies to this message:
 Message 140 by RAZD, posted 11-10-2017 4:47 PM RAZD has acknowledged this reply

  
RAZD
Member
Posts: 19332
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.2


Message 140 of 140 (823482)
11-10-2017 4:47 PM
Reply to: Message 139 by RAZD
11-10-2017 3:34 PM


Including the Oklo Natural Reactors
quote:
The Workings of an Ancient Nuclear Reactor

Two billion years ago parts of an African uranium deposit spontaneously underwent nuclear fission. The details of this remarkable phenomenon are just now becoming clear

Scientific American: By Alex P. Meshik on January 26, 2009

In May 1972 a worker at a nuclear fuel–processing plant in France noticed something suspicious. He had been conducting a routine analysis of uranium derived from a seemingly ordinary source of ore. As is the case with all natural uranium, the material under study contained three isotopes— that is to say, three forms with differing atomic masses: uranium 238, the most abundant variety; uranium 234, the rarest; and uranium 235, the isotope that is coveted because it can sustain a nuclear chain reaction. Elsewhere in the earth’s crust, on the moon and even in meteorites, uranium 235 atoms make up 0.720 percent of the total. But in these samples, which came from the Oklo deposit in Gabon (a former French colony in west equatorial Africa), uranium 235 constituted just 0.717 percent. That tiny discrepancy was enough to alert French scientists that something strange had happened. Further analyses showed that ore from at least one part of the mine was far short on uranium 235: some 200 kilograms appeared to be missing ....

... In 1953 George W. Wetherill of the University of California at Los Angeles and Mark G. Inghram of the University of Chicago pointed out that some uranium deposits might have once operated as natural versions of the nuclear fission reactors that were then becoming popular. Shortly thereafter, Paul K. Kuroda, a chemist from the University of Arkansas, calculated what it would take for a uraniumore body spontaneously to undergo selfsustained fission. ...

Kuroda’s first condition was that the size of the uranium deposit should exceed the average length that fission-inducing neutrons travel, about two thirds of a meter. This requirement helps to ensure that the neutrons given off by one fissioning nucleus are absorbed by another before escaping from the uranium vein.

A second prerequisite is that uranium 235 must be present in sufficient abundance. Today even the most massive and concentrated uranium deposit cannot become a nuclear reactor, because the uranium 235 concentration, at less than 1 percent, is just too low. But this isotope is radioactive and decays about six times faster than does uranium 238, which indicates that the fissile fraction was much higher in the distant past. For example, two billion years ago (about when the Oklo deposit formed) uranium 235 must have constituted approximately 3 percent, which is roughly the level provided artificially in the enriched uranium used to fuel most nuclear power stations.

The third important ingredient is a neutron “moderator,” a substance that can slow the neutrons given off when a uranium nucleus splits so that they are more apt to induce other uranium nuclei to break apart. Finally, there should be no significant amounts of boron, lithium or other so-called poisons, which absorb neutrons and would thus bring any nuclear reaction to a swift halt.

Amazingly, the actual conditions that prevailed two billion years ago in what researchers eventually determined to be 16 separate areas within the Oklo and adjacent Okelobondo uranium mines were very close to what Kuroda outlined ....

Proof in the Light Elements

Physicists confirmed the basic idea that natural fission reactions were responsible for the depletion in uranium 235 at Oklo quite soon after the anomalous uranium was discovered. Indisputable proof came from an examination of the new, lighter elements created when a heavy nucleus is broken in two. The abundance of these fission products proved so high that no other conclusion could be drawn. A nuclear chain reaction very much like the one that Enrico Fermi and his colleagues famously demonstrated in 1942 had certainly taken place, all on its own and some two billion years before.

... some of the neutrons released during the fission of uranium 235 were captured by the more abundant uranium 238, which became uranium 239 and, after emitting two electrons, turned into plutonium 239. More than two tons of this plutonium isotope were generated within the Oklo deposit. Although almost all this material, which has a 24,000-year halflife, has since disappeared (primarily through natural radioactive decay), some of the plutonium itself underwent fission, as attested by the presence of its characteristic fission products. The abundance of those lighter elements allowed scientists to deduce that fission reactions must have gone on for hundreds of thousands of years ....

Nature’s Operating Schedule

After my colleagues and I had worked out in a general way how the observed set of xenon isotopes was created inside the aluminum phosphate grains, we attempted to model the process mathematically. This exercise revealed much about the timing of reactor operation, with all xenon isotopes providing pretty much the same answer. The Oklo reactor we studied had switched “on” for 30 minutes and “off” for at least 2.5 hours. The pattern is not unlike what one sees in some geysers, which slowly heat up, boil off their supply of groundwater in a spectacular display, refill, and repeat the cycle, day in and day out, year after year. This similarity supports the notion not only that groundwater passing through the Oklo deposit was a neutron moderator but also that its boiling away at times accounted for the self-regulation that protected these natural reactors from destruction. In this regard, it was extremely effective, allowing not a single meltdown or explosion during hundreds of thousands of years. ...


So one of the results was that the decay process produced not just alpha and beta decay particles and the isotopes made by their removal by decay, but also the rarer fission into two much larger products: the "new, lighter elements" and their abundance confirmed that a nuclear chain reaction similar to what is seen in man-made reactors. We also see that the "plutonium itself underwent fission, as attested by the presence of its characteristic fission products."

What happens with a decay chain is that isotope after isotope is produced until a much smaller stable element is created by the removal of the decay particles.

But there is also an aspect of this decay process called ...

quote:
secular equilibrium

Secular equilibrium can only occur in a radioactive decay chain if the half-life of the daughter radionuclide B is much shorter than the half-life of the parent radionuclide A. In such a situation, the decay rate of A, and hence the production rate of B, is approximately constant, because the half-life of A is very long compared to the timescales being considered. The quantity of radionuclide B builds up until the number of B atoms decaying per unit time becomes equal to the number being produced per unit time; the quantity of radionuclide B then reaches a constant, equilibrium value. Assuming the initial concentration of radionuclide B is zero, full equilibrium usually takes several half-lives of radionuclide B to establish.

The quantity of radionuclide B when secular equilibrium is reached is determined by the quantity of its parent A and the half-lives of the two radionuclide. ...


Radionuclide B also produces a radionuclide C that can be in secular equilibrium , and on down to the final stable isotope.

This means that the proportions of the different decay products in a decay chain that has existed long enough to reach secular equilibrium at all levels would have specific proportions that depend on the individual isotope half-lives.

Changing the half-life of one isotope creates different changes to the other isotopes (see Message 139 above) and thus the secular equilibrium would result in a different set of proportions of the decay chain isotopes.

This was not observed at the Oklo Natural Reactors even though massive investigation and testing and evaluations were done. What they found was the same as observed in man-made reactors.

Remember that the Oklo Natural Reactors were found because the secular equilibrium level for 235U was only 99.6% of the natural decay uranium secular equilibrium levels (0.717% instead of 0.720%).

Logical Conclusion: the decay rates have not changed for over 2 billion years.

Enjoy

Edited by RAZD, : .


we are limited in our ability to understand
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RebelAmerican☆Zen☯Deist
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This message is a reply to:
 Message 139 by RAZD, posted 11-10-2017 3:34 PM RAZD has acknowledged this reply

  
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