daws101
Diamond Member
- Banned
- #6,481
yours is a dodge the heads of what fields in what sciences
if your talking about entropy everyone excepts it as fact but not that god did it. so again you're intentionally misrepresenting the facts .
as to this: If the moon had started receding from being in contact with the earth, it would have taken only 1.37 billion years to reach its present distance. This is the maximum possible age far too young for evolution and much younger than the radiometric dating method assigned to moon rocks. What say you ?
i say your're full of shit:
Modern dating methodsRadiometric dating has been carried out since 1905 when it was invented by Ernest Rutherford as a method by which one might determine the age of the Earth. In the century since then the techniques have been greatly improved and expanded.[14] Dating can now be performed on samples as small as a nanogram using a mass spectrometer. The mass spectrometer was invented in the 1940s and began to be used in radiometric dating in the 1950s. The mass spectrometer operates by generating a beam of ionized atoms from the sample under test. The ions then travel through a magnetic field, which diverts them into different sampling sensors, known as "Faraday cups", depending on their mass and level of ionization. On impact in the cups, the ions set up a very weak current that can be measured to determine the rate of impacts and the relative concentrations of different atoms in the beams.
[edit] Uranium-lead dating methodMain article: uranium-lead dating
A concordia diagram as used in uranium-lead dating, with data from the Pfunze Belt, Zimbabwe.[16] All the samples show loss of lead isotopes, but the intercept of the errorchron (straight line through the sample points) and the concordia (curve) shows the correct age of the rock.[11]The uranium-lead radiometric dating scheme has been refined to the point that the error margin in dates of rocks can be as low as less than two million years in two-and-a-half billion years.[12][17] An error margin of 2–5 % has been achieved on younger Mesozoic rocks.[18]
Uranium-lead dating is often performed on the mineral zircon (ZrSiO4), though it can be used on other materials, such as baddeleyite.[19] Zircon and baddeleyite incorporate uranium atoms into their crystalline structure as substitutes for zirconium, but strongly reject lead. It has a very high closure temperature, is resistant to mechanical weathering and is very chemically inert. Zircon also forms multiple crystal layers during metamorphic events, which each may record an isotopic age of the event. In situ micro-beam analysis can be achieved via laser ICP-MS or SIMS techniques.[20]
One of its great advantages is that any sample provides two clocks, one based on uranium-235's decay to lead-207 with a half-life of about 700 million years, and one based on uranium-238's decay to lead-206 with a half-life of about 4.5 billion years, providing a built-in crosscheck that allows accurate determination of the age of the sample even if some of the lead has been lost. This can be seen in the concordia diagram, where the samples plot along an errorchron (straight line) which intersects the concordia curve at the age of the sample.
[edit] Samarium-neodymium dating methodMain article: Samarium-neodymium dating
This involves the alpha-decay of 147Sm to 143Nd with a half-life of 1.06 x 1011 years. Accuracy levels of less than twenty million years in two-and-a-half billion years are achievable.[21]
[edit] Potassium-argon dating methodMain article: Potassium-argon dating
This involves electron capture or positron decay of potassium-40 to argon-40. Potassium-40 has a half-life of 1.3 billion years, and so this method is applicable to the oldest rocks. Radioactive potassium-40 is common in micas, feldspars, and hornblendes, though the closure temperature is fairly low in these materials, about 125°C (mica) to 450°C (hornblende).
[edit] Rubidium-strontium dating methodMain article: Rubidium-strontium dating
This is based on the beta decay of rubidium-87 to strontium-87, with a half-life of 50 billion years. This scheme is used to date old igneous and metamorphic rocks, and has also been used to date lunar samples. Closure temperatures are so high that they are not a concern. Rubidium-strontium dating is not as precise as the uranium-lead method, with errors of 30 to 50 million years for a 3-billion-year-old sample.
[edit] Uranium-thorium dating methodMain article: uranium-thorium dating
A relatively short-range dating technique is based on the decay of uranium-234 into thorium-230, a substance with a half-life of about 80,000 years. It is accompanied by a sister process, in which uranium-235 decays into protactinium-231, which has a half-life of 34,300 years.
While uranium is water-soluble, thorium and protactinium are not, and so they are selectively precipitated into ocean-floor sediments, from which their ratios are measured. The scheme has a range of several hundred thousand years. A related method is ionium-thorium dating, which measures the ratio of ionium (thorium-230) to thorium-232 in ocean sediment.
[edit] Radiocarbon dating methodMain article: Radiocarbon dating
Ale's Stones at Kåseberga, around ten kilometres south east of Ystad, Sweden were dated at 600 CE using the carbon-14 method on organic material found at the site.[22]Carbon-14 is a radioactive isotope of carbon, with a half-life of 5,730 years,[23][24] which is very short compared with the above isotopes. In other radiometric dating methods, the heavy parent isotopes were produced by nucleosynthesis in supernovas, meaning that any parent isotope with a short half-life should be extinct by now. Carbon-14, though, is continuously created through collisions of neutrons generated by cosmic rays with nitrogen in the upper atmosphere and thus remains at a near-constant level on Earth. The carbon-14 ends up as a trace component in atmospheric carbon dioxide (CO2).
An organism acquires carbon during its lifetime. Plants acquire it through photosynthesis, and animals acquire it from consumption of plants and other animals. When an organism dies, it ceases to take in new carbon-14, and the existing isotope decays with a characteristic half-life (5730 years). The proportion of carbon-14 left when the remains of the organism are examined provides an indication of the time elapsed since its death. The carbon-14 dating limit lies around 58,000 to 62,000 years.[25]
The rate of creation of carbon-14 appears to be roughly constant, as cross-checks of carbon-14 dating with other dating methods show it gives consistent results. However, local eruptions of volcanoes or other events that give off large amounts of carbon dioxide can reduce local concentrations of carbon-14 and give inaccurate dates. The releases of carbon dioxide into the biosphere as a consequence of industrialization have also depressed the proportion of carbon-14 by a few percent; conversely, the amount of carbon-14 was increased by above-ground nuclear bomb tests that were conducted into the early 1960s. Also, an increase in the solar wind or the Earth's magnetic field above the current value would depress the amount of carbon-14 created in the atmosphere. These effects are corrected for by the calibration of the radiocarbon dating scale.[26]
[edit] Fission track dating methodMain article: fission track dating
Apatite crystals are widely used in fission track dating.This involves inspection of a polished slice of a material to determine the density of "track" markings left in it by the spontaneous fission of uranium-238 impurities. The uranium content of the sample has to be known, but that can be determined by placing a plastic film over the polished slice of the material, and bombarding it with slow neutrons. This causes induced fission of 235U, as opposed to the spontaneous fission of 238U. The fission tracks produced by this process are recorded in the plastic film. The uranium content of the material can then be calculated from the number of tracks and the neutron flux.
This scheme has application over a wide range of geologic dates. For dates up to a few million years micas, tektites (glass fragments from volcanic eruptions), and meteorites are best used. Older materials can be dated using zircon, apatite, titanite, epidote and garnet which have a variable amount of uranium content.[27] Because the fission tracks are healed by temperatures over about 200°C the technique has limitations as well as benefits. The technique has potential applications for detailing the thermal history of a deposit.
[edit] Chlorine-36 dating methodLarge amounts of otherwise rare 36Cl were produced by irradiation of seawater during atmospheric detonations of nuclear weapons between 1952 and 1958. The residence time of 36Cl in the atmosphere is about 1 week. Thus, as an event marker of 1950s water in soil and ground water, 36Cl is also useful for dating waters less than 50 years before the present. 36Cl has seen use in other areas of the geological sciences, including dating ice and sediments.
[edit] Luminescence dating methodsMain articles: Optical dating and Thermoluminescence dating
Natural sources of radiation in the environment knock loose electrons in, say, a piece of pottery, and these electrons accumulate in defects in the material's crystal lattice structure. Heating or illuminating the object will release the captured electrons, producing a luminescence. When the sample is heated, at a certain temperature it will glow from the emission of electrons released from the defects, and this glow can be used to estimate the age of the sample to a threshold of approximately 15 percent of its true age. The date of a rock is reset when volcanic activity remelts it. The date of a piece of pottery is reset by the heat of the kiln. Typically temperatures greater than 400 degrees Celsius will reset the "clock". This is termed thermoluminescence.
[edit] Other methodsOther methods include:
argon-argon (Ar-Ar)
iodine-xenon (I-Xe)
lanthanum-barium (La-Ba)
lead-lead (Pb-Pb)
lutetium-hafnium (Lu-Hf)
neon-neon (Ne-Ne)
rhenium-osmium (Re-Os)
uranium-lead-helium (U-Pb-He)
uranium-uranium (U-U)
