Since its interaction with normal matter is incredibly weak, it can very easily pass through the earth. Not to mention that different models of dark matter would lead to different interactions. Are we able to calculate the mass of the earth from our knowledge of its contents, and not just the gravitational force we detect? I think if there were much dark matter in the earth, it would be noticeable.
Accuracy of Fossils and Dating Methods
We also know the overall composition of the crust and mantle from samples. Thus, the only real unknown is the composition of the core. Using the mass and all those other measurements, we deduce that the core is mostly iron with some nickel. I fear it is more a matter of philosophy rather than hard science: The problem with that, is that, in the first case, there appear to be no transitional fossils when there should be millions , and to make the assumption previously herein stated, evolutionary conclusions are more akin to a combination of wishful thinking combined with a sympathetic magic mindset, than to observable examples.
Evolution is taught as established fact, and scientific enquiry is severely trammelled by those who prefer a status quo. Every fossil between organisms alive now and abiogenesis is a transitional fossil, Tony. There are also transitional fossils and organisms in the misguided definition of the word you are using. I admire your faith, Cromwell.
Yet you state it as fact. Then, you claim that all fossils are a transition between that unrealistic event and the life we see now. Thanks for writing an informative article. Error bars have their place, but you are correct in pointing out that they are often misunderstood not only by the general public, but by scientists who are not savvy in radiometric dating.
I would have worded this sentence differently: I am not convinced that differential diffusion of isotopes will be all that significant. After all, fractionation of light elements, such as oxygen, provides us with all sorts of insights into geologic processes because the mass difference between O and O is rather significant, whereas the mass difference between Sr and Sr is not all that great, in terms of ratios. The differences are even less significant for more massive isotopes such as in samarium-neodymium dating Nd and Nd If fractionation does turn out to be important for isochrons, one would expect that there would be a trend, with lighter nuclides e.
Rb-Sr being more affected than heavier nuclides e. I am also wondering if Dr. Hays addressed how isotope fractionation would affect U-series concordia diagrams. As it is, there is a general correlation of dates obtained by radiometric dating from the top to the bottom of the geologic column.
Strongly discordant dates happen and young-Earth creationists focus on these , but roughly concordant dates are common; otherwise geologists would not trust the methods. It seems strange, if diffusion is a problem, that nuclides with very different masses are effected in the same way. Perhaps Earth is only 3. This would require similar diffusion rates in cold meteorites as in warm crustal zircons.
This would be very interesting, and would cause geologists to have to re-write many books, but the general story of geology would stand. This is because geologists do not believe Earth is billions of years old because of radiometric dating. Radiometric tools merely give us firm pegs to hang our signs on for the various eras, periods, and epochs of Earth history. Thanks for your comment, Kevin. I would have to disagree with your suggested change in wording, however.
Scientist Realizes Important Flaw in Radioactive Dating – Proslogion
While most definitely not all geochronologists do understand that there are false isochrons, that is never the way it is presented to students or the general public. This is unfortunate, of course, but it seems to be the norm when propaganda replaces science. I think what you are missing is the chemistry involved. When we are dealing with trace elements not substances that are part of the crystal lattice , differential diffusion can have a significant effect. It is also not clear that there would be a general trend like you suggest. Diffusion also depends on chemical issues.
When you are dealing with different elements, you are dealing with completely different diffusion scenarios. Hayes discussing uranium-series dating. Since concordia diagrams also involve isotope ratios, however, I suspect that this problem exists there as well. In fact, they might even be the majority. I have no doubt that those who want to believe in an old earth will be able figure out a way to keep the overall story of geology the same, regardless of how important this effect turns out to be, if that can even be determined to any reasonable precision.
Yes, there are other issues at play as is the case with any over-arching scientific idea , but to her, radiometric dating is the most important reason she believes in an old earth.
I have no idea whether she is the norm or the exception, but she does exist. I was wondering how diffusion made any sense….
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When I started my journey from old earth-evolutionism, it was much easier to see the flaws in evolutionary theory than those in the old age model. Thanks for your personal story, SJ. I guess that makes at least two geologists for whom radioactive dating was a big factor in their belief in an old earth. I am glad that you eventually saw the problems associated with that. Rubidium readily substitutes for potassium in the crystal lattice of minerals, and strontium readily substitutes for calcium.
Rb and Sr are still considered to be trace elements, even when incorporated into the lattice. When Rb decays to Sr, the resulting strontium ion is chemically out of place in the lattice structure. Dr Wiles, Thanks for your response. What might we find if we can dip into the magma and test it immediately?
Seems like that might be a good calibration for these radioisotopes. Many radioactive dating systems start with an assumption about what happens at the point of solidification. Thus, any argon in the rock must have come from radioactive decay. In all cases, there is a lot of argon in the rock, indicating that the assumption is false.
I am not sure what directly testing mantle magma will tell us about radioactive dating, because lots of things happen to the lava as it is flowing over the surface of the earth. Obviously, directly sampling mantle magma will tell us a lot, but I am not sure if it will tell us anything about radioactive dating. The samples from the mantle would not be magma, but solid rock. The mantle is almost entirely solid. We already have samples of the mantle, in the form of inclusions e. Ophiolites have, in general, been altered from their original form, so pieces of raw, unaltered mantle rock would make for a number of interesting studies.
It is a bit in between. April 3, at April 3, at 1: April 4, at April 7, at 6: April 7, at 9: April 7, at April 5, at 5: April 5, at 7: April 5, at 8: April 5, at April 6, at 9: April 7, at 7: April 7, at 8: April 8, at 7: Paleontologists still commonly use biostratigraphy to date fossils, often in combination with paleomagnetism and tephrochronology. A submethod within biostratigraphy is faunal association: Sometimes researchers can determine a rough age for a fossil based on established ages of other fauna from the same layer — especially microfauna, which evolve faster, creating shorter spans in the fossil record for each species.
The polarity is recorded by the orientation of magnetic crystals in specific kinds of rock, and researchers have established a timeline of normal and reversed periods of polarity.
The Age of the Earth
Paleomagnetism is often used as a rough check of results from another dating method. Within hours or days of a volcanic eruption, tephra — fragments of rock and other material hurled into the atmosphere by the event — is deposited in a single layer with a unique geochemical fingerprint. Researchers can first apply an absolute dating method to the layer.
They then use that absolute date to establish a relative age for fossils and artifacts in relation to that layer. Anything below the Taupo tephra is earlier than ; anything above it is later. Generally speaking, the more complex a poem or piece of pottery is, the more advanced it is and the later it falls in the chronology.
Egyptologists, for example, created a relative chronology of pre-pharaonic Egypt based on increasing complexity in ceramics found at burial sites. Sometimes called carbon dating, this method works on organic material. Both plants and animals exchange carbon with their environment until they die. Afterward, the amount of the radioactive isotope carbon in their remains decreases. Measuring carbon in bones or a piece of wood provides an accurate date, but only within a limited range. It would be like having a watch that told you day and night.
Also called single crystal argon or argon-argon Ar-Ar dating, this method is a refinement of an older approach known as potassium-argon K-Ar dating, which is still sometimes used. Both methods date rock instead of organic material. As potassium decays, it turns into argon. But unlike radiocarbon dating, the older the sample, the more accurate the dating — researchers typically use these methods on finds at least , years old.
While K-Ar dating requires destroying large samples to measure potassium and argon levels separately, Ar-Ar dating can analyze both at once with a single, smaller sample. The uranium-thorium method is often helpful for dating finds in the 40, to ,year-old range, too old for radiocarbon but too young for K-Ar or Ar-Ar. Silicate rocks, like quartz, are particularly good at trapping electrons.
Researchers who work with prehistoric tools made from flint — a hardened form of quartz — often use thermoluminescence TL to tell them not the age of the rock, but of the tool. After shaping flint, toolmakers typically dropped the rocks into a fire. Archaeologists also frequently use TL to date ceramics, which are also exposed to high temperatures during manufacture.
Similar to TL, optically stimulated luminescence measures when quartz crystals in certain kinds of rock last saw sunlight. That emitted light, the signal, can be used to calculate when the sample was last exposed to sunlight.