46AND2
Forty six and two are just ahead of me...
- Sep 5, 2012
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If anyone here is familiar with the formulas behind this, can you please explain it to me in layman's terms? I recall hearing that decay rates of isotopes are tied to equations, and that if decay rates used to be higher in the past it messes things up in particle physics.
Obviously I can't quite explain what I'm after, or else I wouldn't need it explained to me.If you know what I'm getting at could you please help?
I realize this is an old thread, and I'm not sure if this will answer your question or not, but I'll give it a shot, anyway.
Keep in mind, I'm a layman concerning this stuff as well, but it is an interest of mine. I'm planning on going back into school to get into geochronology. Anyone with more expertise, please feel free to correct any mistakes I may make.
Your statement that particle physics would be messed up if decay rates used to be higher is kind of backwards. In fact, in order for decay rates to be different, particle physics would have to change; decay is the result of interactions of atomic particles and their attractive and repulsive forces.
The reason why decay rates are so consistent, and virtually unaffected by any natural processes is that the decay involves changes in the nucleus of the atom (ejections and electron capture, for example), and it takes very large amounts of energy to affect the nuclei.
For instance, the energy it takes for chemical forces to bind atoms together to form molecules is about one electron volt. The force for electrons to be tied to nuclei is between 10 and 100 electron volts. The nuclear binding energy, however, is about a million electron volts. This is why it takes nuclear reactors and particle accelerators to make changes in the nucleus. There simply is no "known" natural phenomena that can account for that amount of energy required, other than radioactive decay.
The way that radioactive decay overcomes this nuclear force is because the more protons that are contained in the nucleus (i.e., the heavier the element), the more electrical force there is working against the nuclear force. This is because protons repel each other due to their positive charge. The more protons that are confined in such a small space, the more electrical force there will be.
In order for the nucleus to remain stable, the nuclear force has to be stronger than the electrical force working against it. For this to happen, the nucleus will need more neutrons--which are attracted to each other and to protons through the nuclear force--to help offset the electrical force of proton repulsion. Different isotopes will have dissimilar ratios of neutrons to protons, and this ratio determines how stable the isotope is based on how well it offsets the electrical force.
The more stable the isotope, the longer the half-life will be. However, due to the instability of the isotope, the nucleus will spontaneously eject an alpha particle (for example; considered alpha decay), due to the electrical force of proton repulsion overcoming the nuclear force. The alpha particle is a helium nucleus (2 protons, 2 neutrons).
Even though the ejection is random and spontaneous, it can be measured as a constant through probability due to the law of large numbers. Simply put, there are so many atoms in a sample at a given time, that the randomness of the decay becomes constant over time.
Many experiments have been performed attempting to determine if the decay rates are variable using known forces, such as extreme temperature, pressure, magnetic and electrical fields--usually done at rates far greater than has been observed in nature. No decay rate has been affected by more than .18% in any isotope, and no isotope that is used in radiometric dating has shown any measurable change.
So, the question is...could there be some force as yet undiscovered that could dramatically affect the decay rate? Well, of course we can never rule things out of which we are completely ignorant. That is, after all, why science cannot "prove" anything with 100% certainty. But we can't go around dismissing measurement tools simply because there "might" be some chance that the tool is affected by an unknown force.
Shall we stop using weighing scales because there "might" be some unknown force which makes all scales technically inaccurate, even though there is complete agreement between different types of scales; analog, digital, balance, hanging? Of course not. And that is why it is highly unlikely that there is an unknown force which once affected decay rates. Different isotopes have different binding energies, electrical energies, and stability, and as such any force that might affect decay rates, will affect different isotopes by different amounts. This would make it virtually impossible for us to get convergent results if we use multiple radiometric techniques on the same sample. Yet this is exactly what we see. We get the same results whether we use Rb-Sr or U-Pb dating.
In addition to that, the results ALSO converge with techniques that are completely unrelated to radioactivity. So, even if there did happen to be a force which managed to affect all decay rates perfectly, it certainly could not also affect the the non-radiometric technique equally perfectly and consistently with radiometric techniques.
So hopefully I explained this well enough so that you can see that in order for decay rates to be different, basic principles of chemistry and nuclear physics have to be different. We have no reason to believe this could have happened due to the agreement of results from multiple different isotopes and non-radiometric dating techniques alike.
There is much more to it than this, of course, but if you study some of the key words I've mentioned (particularly the bolded terms), you should be able to learn the key points in greater detail.
I don't think this is entirely true. If I'm not mistaken, a change in the speed of light would change the binding energy of the nuclei (since the binding energy is found using the formula E=mc^2) and the stability of the isotopes, which would change the decay rate.
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