Language tree rooted in Turkey
On the other hand, if the Argon has a place to go, as in a vacuum, then the Argon will escape out of the rock. Edgerton did not consider himself be to an artist nor his photos to be artworks, but many collect his photos as artworks and they are hung in art museums. In fact, the variations were so common they couldn't be accidental mutations but instead were probably due to natural selection, where genetic changes that are favorable to a species quickly gain a foothold and begin to spread, the researchers report. K-Ar dating is not based on irrefutable data alone.
However, when the volcanic lava flow, goes underwater, into the sea; It shows progressively excess ages. The envoy, journeying to Aratta, covered his feet with the dust of the road and stirred up the pebbles of the mountains. Cosmic ray exposure calibrations must take into. The novelty alone produces an aesthetic and emotional reaction sometimes good, sometimes bad. This analysis can be non-destructive— meaning no sample has to be removed from the object— and can often be be done on sight.
Rightly Handling the Word of Truth Appendix: Arguments over the age of the Earth have sometimes been divisive for people who regard the Bible as God's word. Even though the Earth's age is never mentioned in the Bible, it is an issue because those who take a strictly literal view of the early chapters of Genesis can calculate an approximate date for the creation by adding up the life-spans of the people mentioned in the genealogies.
Assuming a strictly literal interpretation of the week of creation, even if some of the generations were left out of the genealogies, the Earth would be less than ten thousand years old. Radiometric dating techniques indicate that the Earth is thousands of times older than that--approximately four and a half billion years old.
Many Christians accept this and interpret the Genesis account in less scientifically literal ways. However, some Christians suggest that the geologic dating techniques are unreliable, that they are wrongly interpreted, or that they are confusing at best.
Unfortunately, much of the literature available to Christians has been either inaccurate or difficult to understand, so that confusion over dating techniques continues. The next few pages cover a broad overview of radiometric dating techniques, show a few examples, and discuss the degree to which the various dating systems agree with each other.
The goal is to promote greater understanding on this issue, particularly for the Christian community. Many people have been led to be skeptical of dating without knowing much about it. For example, most people don't realize that carbon dating is only rarely used on rocks. God has called us to be "wise as serpents" Matt. In spite of this, differences still occur within the church. A disagreement over the age of the Earth is relatively minor in the whole scope of Christianity; it is more important to agree on the Rock of Ages than on the age of rocks.
But because God has also called us to wisdom, this issue is worthy of study. Rocks are made up of many individual crystals, and each crystal is usually made up of at least several different chemical elements such as iron, magnesium, silicon, etc. Most of the elements in nature are stable and do not change. However, some elements are not completely stable in their natural state. Some of the atoms eventually change from one element to another by a process called radioactive decay. If there are a lot of atoms of the original element, called the parent element, the atoms decay to another element, called the daughter element, at a predictable rate.
The passage of time can be charted by the reduction in the number of parent atoms, and the increase in the number of daughter atoms. Radiometric dating can be compared to an hourglass. When the glass is turned over, sand runs from the top to the bottom. Radioactive atoms are like individual grains of sand--radioactive decays are like the falling of grains from the top to the bottom of the glass. You cannot predict exactly when any one particular grain will get to the bottom, but you can predict from one time to the next how long the whole pile of sand takes to fall.
Once all of the sand has fallen out of the top, the hourglass will no longer keep time unless it is turned over again. Similarly, when all the atoms of the radioactive element are gone, the rock will no longer keep time unless it receives a new batch of radioactive atoms. The rate of loss of sand from from the top of an hourglass compared to exponential type of decay of radioactive elements.
In exponential decay the amount of material decreases by half during each half-life. After two half-lives one-fourth remains, after three half-lives, one-eighth, etc. Unlike the hourglass, where the amount of sand falling is constant right up until the end, the number of decays from a fixed number of radioactive atoms decreases as there are fewer atoms left to decay see Figure 1. If it takes a certain length of time for half of the atoms to decay, it will take the same amount of time for half of the remaining atoms, or a fourth of the original total, to decay.
In the next interval, with only a fourth remaining, only one eighth of the original total will decay. By the time ten of these intervals, or half-lives, has passed, less than one thousandth of the original number of radioactive atoms is left. The equation for the fraction of parent atoms left is very simple. The type of equation is exponential, and is related to equations describing other well-known phenomena such as population growth.
No deviations have yet been found from this equation for radioactive decay. Also unlike the hourglass, there is no way to change the rate at which radioactive atoms decay in rocks. If you shake the hourglass, twirl it, or put it in a rapidly accelerating vehicle, the time it takes the sand to fall will change.
But the radioactive atoms used in dating techniques have been subjected to heat, cold, pressure, vacuum, acceleration, and strong chemical reactions to the extent that would be experienced by rocks or magma in the mantle, crust, or surface of the Earth or other planets without any significant change in their decay rate.
In only a couple of special cases have any decay rates been observed to vary, and none of these special cases apply to the dating of rocks as discussed here. These exceptions are discussed later. An hourglass will tell time correctly only if it is completely sealed. If it has a hole allowing the sand grains to escape out the side instead of going through the neck, it will give the wrong time interval. Similarly, a rock that is to be dated must be sealed against loss or addition of either the radioactive daughter or parent.
If it has lost some of the daughter element, it will give an inaccurately young age. As will be discussed later, most dating techniques have very good ways of telling if such a loss has occurred, in which case the date is thrown out and so is the rock!
An hourglass measures how much time has passed since it was turned over. Actually it tells when a specific amount of time, e. Radiometric dating of rocks also tells how much time has passed since some event occurred. For igneous rocks the event is usually its cooling and hardening from magma or lava. For some other materials, the event is the end of a metamorphic heating event in which the rock gets baked underground at generally over a thousand degrees Fahrenheit , the uncovering of a surface by the scraping action of a glacier, the chipping of a meteorite off of an asteroid, or the length of time a plant or animal has been dead.
There are now well over forty different radiometric dating techniques, each based on a different radioactive isotope. The term isotope subdivides elements into groups of atoms that have the same atomic weight. For example carbon has isotopes of weight 12, 13, and 14 times the mass of a nucleon, referred to as carbon, carbon, or carbon abbreviated as 12 C, 13 C, 14 C.
It is only the carbon isotope that is radioactive. This will be discussed further in a later section. A partial list of the parent and daughter isotopes and the decay half-lives is given in Table I. Notice the large range in the half-lives. Isotopes with long half-lives decay very slowly, and so are useful for dating.
Some Naturally Occurring Radioactive Isotopes and their half-lives. Years Samarium Neodymium billion Rubidium Strontium Isotopes with shorter half-lives cannot date very ancient events because all of the atoms of the parent isotope would have already decayed away, like an hourglass left sitting with all the sand at the bottom.
Isotopes with relatively short half-lives are useful for dating correspondingly shorter intervals, and can usually do so with greater accuracy, just as you would use a stopwatch rather than a grandfather clock to time a meter dash. On the other hand, you would use a calendar, not a clock, to record time intervals of several weeks or more. The half-lives have all been measured directly either by using a radiation detector to count the number of atoms decaying in a given amount of time from a known amount of the parent material, or by measuring the ratio of daughter to parent atoms in a sample that originally consisted completely of parent atoms.
Work on radiometric dating first started shortly after the turn of the 20th century, but progress was relatively slow before the late. However, by now we have had over fifty years to measure and re-measure the half-lives for many of the dating techniques.
Very precise counting of the decay events or the daughter atoms can be done, so while the number of, say, rhenium atoms decaying in 50 years is a very small fraction of the total, the resulting osmium atoms can be very precisely counted. For example, recall that only one gram of material contains over 10 21 1 with 21 zeros behind atoms. Even if only one trillionth of the atoms decay in one year, this is still millions of decays, each of which can be counted by a radiation detector!
The uncertainties on the half-lives given in the table are all very small. There is no evidence of any of the half-lives changing over time. In fact, as discussed below, they have been observed to not change at all over hundreds of thousands of years. Examples of Dating Methods for Igneous Rocks. Now let's look at how the actual dating methods work. Igneous rocks are good candidates for dating. Recall that for igneous rocks the event being dated is when the rock was formed from magma or lava.
When the molten material cools and hardens, the atoms are no longer free to move about. Daughter atoms that result from radioactive decays occurring after the rock cools are frozen in the place where they were made within the rock. These atoms are like the sand grains accumulating in the bottom of the hourglass. Determining the age of a rock is a two-step process. First one needs to measure the number of daughter atoms and the number of remaining parent atoms and calculate the ratio between them.
Then the half-life is used to calculate the time it took to produce that ratio of parent atoms to daughter atoms. However, there is one complication. One cannot always assume that there were no daughter atoms to begin with. It turns out that there are some cases where one can make that assumption quite reliably.
But in most cases the initial amount of the daughter product must be accurately determined. Most of the time one can use the different amounts of parent and daughter present in different minerals within the rock to tell how much daughter was originally present. Each dating mechanism deals with this problem in its own way. Some types of dating work better in some rocks; others are better in other rocks, depending on the rock composition and its age.
Let's examine some of the different dating mechanisms now. Potassium is an abundant element in the Earth's crust. One isotope, potassium, is radioactive and decays to two different daughter products, calcium and argon, by two different decay methods.
This is not a problem because the production ratio of these two daughter products is precisely known, and is always constant: It is possible to date some rocks by the potassium-calcium method, but this is not often done because it is hard to determine how much calcium was initially present.
Argon, on the other hand, is a gas. Whenever rock is melted to become magma or lava, the argon tends to escape. Once the molten material hardens, it begins to trap the new argon produced since the hardening took place. In this way the potassium-argon clock is clearly reset when an igneous rock is formed.
In its simplest form, the geologist simply needs to measure the relative amounts of potassium and argon to date the rock. The age is given by a relatively simple equation:. However, in reality there is often a small amount of argon remaining in a rock when it hardens. This is usually trapped in the form of very tiny air bubbles in the rock.
One percent of the air we breathe is argon. Any extra argon from air bubbles may need to be taken into account if it is significant relative to the amount of radiogenic argon that is, argon produced by radioactive decays. This would most likely be the case in either young rocks that have not had time to produce much radiogenic argon, or in rocks that are low in the parent potassium.
One must have a way to determine how much air-argon is in the rock. This is rather easily done because air-argon has a couple of other isotopes, the most abundant of which is argon The ratio of argon to argon in air is well known, at Thus, if one measures argon as well as argon, one can calculate and subtract off the air-argon to get an accurate age.
One of the best ways of showing that an age-date is correct is to confirm it with one or more different dating. Although potassium-argon is one of the simplest dating methods, there are still some cases where it does not agree with other methods. When this does happen, it is usually because the gas within bubbles in the rock is from deep underground rather than from the air. This gas can have a higher concentration of argon escaping from the melting of older rocks.
This is called parentless argon because its parent potassium is not in the rock being dated, and is also not from the air. In these slightly unusual cases, the date given by the normal potassium-argon method is too old. However, scientists in the mids came up with a way around this problem, the argon-argon method, discussed in the next section.
Even though it has been around for nearly half a century, the argon-argon method is seldom discussed by groups critical of dating methods. This method uses exactly the same parent and daughter isotopes as the potassium-argon method. In effect, it is a different way of telling time from the same clock. Instead of simply comparing the total potassium with the non-air argon in the rock, this method has a way of telling exactly what and how much argon is directly related to the potassium in the rock.
In the argon-argon method the rock is placed near the center of a nuclear reactor for a period of hours. A nuclear reactor emits a very large number of neutrons, which are capable of changing a small amount of the potassium into argon Argon is not found in nature because it has only a year half-life.
This half-life doesn't affect the argon-argon dating method as long as the measurements are made within about five years of the neutron dose.
The rock is then heated in a furnace to release both the argon and the argon representing the potassium for analysis. The heating is done at incrementally higher temperatures and at each step the ratio of argon to argon is measured. If the argon is from decay of potassium within the rock, it will come out at the same temperatures as the potassium-derived argon and in a constant proportion. On the other hand, if there is some excess argon in the rock it will cause a different ratio of argon to argon for some or many of the heating steps, so the different heating steps will not agree with each other.
Figure 2 is an example of a good argon-argon date. The fact that this plot is flat shows that essentially all of the argon is from decay of potassium within the rock. The potassium content of the sample is found by multiplying the argon by a factor based on the neutron exposure in the reactor. When this is done, the plateau in the figure represents an age date based on the decay of potassium to argon There are occasions when the argon-argon dating method does not give an age even if there is sufficient potassium in the sample and the rock was old enough to date.
This most often occurs if the rock experienced a high temperature usually a thousand degrees Fahrenheit or more at some point since its formation. If that occurs, some of the argon gas moves around, and the analysis does not give a smooth plateau across the extraction temperature steps.
An example of an argon-argon analysis that did not yield an age date is shown in Figure 3. Notice that there is no good plateau in this plot. In some instances there will actually be two plateaus, one representing the formation age, and another representing the time at which the heating episode occurred.
But in most cases where the system has been disturbed, there simply is no date given. The important point to note is that, rather than giving wrong age dates, this method simply does not give a date if the system has been disturbed.
This is also true of a number of other igneous rock dating methods, as we will describe below. In nearly all of the dating methods, except potassium-argon and the associated argon-argon method, there is always some amount of the daughter product already in the rock when it cools.
Using these methods is a little like trying to tell time from an hourglass that was turned over before all of the sand had fallen to the bottom. One can think of ways to correct for this in an hourglass: One could make a mark on the outside of the glass where the sand level started from and then repeat the interval with a stopwatch in the other hand to calibrate it. Or if one is clever she or he could examine the hourglass' shape and determine what fraction of all the sand was at the top to start with.
By knowing how long it takes all of the sand to fall, one could determine how long the time interval was. Similarly, there are good ways to tell quite precisely how much of the daughter product was already in the rock when it cooled and hardened. Figure 4 is an important type of plot used in rubidium-strontium dating.
This works because if there were no rubidium in the sample, the strontium composition would not change. The slope of the line is used to determine the age of the sample. As the rock starts to age, rubidium gets converted to strontium. The amount of strontium added to each mineral is proportional to the amount of rubidium present. The solid line drawn through the samples will thus progressively rotate from the horizontal to steeper and steeper slopes.
From that we can determine the original daughter strontium in each mineral, which is just what we need to know to determine the correct age. It also turns out that the slope of the line is proportional to the age of the rock. The older the rock, the steeper the line will be. If the slope of the line is m and the half-life is h , the age t in years is given by the equation. For a system with a very long half-life like rubidium-strontium, the actual numerical value of the slope will always be quite small.
To give an example for the above equation, if the slope of a line in a plot similar to Fig. Several things can on rare occasions cause problems for the rubidium-strontium dating method. One possible source of problems is if a rock contains some minerals that are older than the main part of the rock. This can happen when magma inside the Earth picks up unmelted minerals from the surrounding rock as the magma moves through a magma chamber. Usually a good geologist can distinguish these "xenoliths" from the younger minerals around them.
If he or she does happen to use them for dating the rock, the points represented by these minerals will lie off the line made by the rest of the points. Another difficulty can arise if a rock has undergone metamorphism, that is, if the rock got very hot, but not hot enough to completely re-melt the rock.
In these cases, the dates look confused, and do not lie along a line. Some of the minerals may have completely melted, while others did not melt at all, so some minerals try to give the igneous age while other minerals try to give the metamorphic age. In these cases there will not be a straight line, and no date is determined. In a few very rare instances the rubidium-strontium method has given straight lines that give wrong ages.
This can happen when the rock being dated was formed from magma that was not well mixed, and which had two distinct batches of rubidium and strontium. One magma batch had rubidium and strontium compositions near the upper end of a line such as in Fig. In this case, the. This is called a two-component mixing line. It is a very rare occurrence in these dating mechanisms, but at least thirty cases have been documented among the tens of thousands of rubidium-strontium dates made.
The agreement of several dating methods is the best fail-safe way of dating rocks. All of these methods work very similarly to the rubidium-strontium method. They all use three-isotope diagrams similar to Figure 4 to determine the age. The samarium-neodymium method is the most-often used of these three.
It uses the decay of samarium to neodymium, which has a half-life of billion years. The ratio of the daughter isotope, neodymium, to another neodymium isotope, neodymium, is plotted against the ratio of the parent, samarium, to neodymium If different minerals from the same rock plot along a line, the slope is determined, and the age is given by the same equation as above.
The samarium-neodymium method may be preferred for rocks that have very little potassium and rubidium, for which the potassium-argon, argon-argon, and rubidium-strontium methods might be difficult. The samarium-neodymium method has also been shown to be more resistant to being disturbed or re-set by metamorphic heating events, so for some metamorphosed rocks the samarium-neodymium method is preferred. For a rock of the same age, the slope on the neodymium-samarium plots will be less than on a rubidium-strontium plot because the half-life is longer.
However, these isotope ratios are usually measured to extreme accuracy--several parts in ten thousand--so accurate dates can be obtained even for ages less than one fiftieth of a half-life, and with correspondingly small slopes. The lutetium-hafnium method uses the 38 billion year half-life of lutetium decaying to hafnium This dating system is similar in many ways to samarium-neodymium, as the elements tend to be concentrated in the same types of minerals.
Since samarium-neodymium dating is somewhat easier, the lutetium-hafnium method is used less often. The rhenium-osmium method takes advantage of the fact that the osmium concentration in most rocks and minerals is very low, so a small amount of the parent rhenium can produce a significant change in the osmium isotope ratio. The half-life for this radioactive decay is 42 billion years. The non-radiogenic stable isotopes, osmium or , are used as the denominator in the ratios on the three-isotope plots.
This method has been useful for dating iron meteorites, and is now enjoying greater use for dating Earth rocks due to development of easier rhenium and osmium isotope measurement techniques. Uranium-Lead and related techniques. The uranium-lead method is the longest-used dating method. It was first used in , about a century ago. The uranium-lead system is more complicated than other parent-daughter systems; it is actually several dating methods put together.
Natural uranium consists primarily of two isotopes, U and U, and these isotopes decay with different half-lives to produce lead and lead, respectively. In addition, lead is produced by thorium Only one isotope of lead, lead, is not radiogenic. The uranium-lead system has an interesting complication: Each decays through a series of relatively short-lived radioactive elements that each decay to a lighter element, finally ending up at lead.
Since these half-lives are so short compared to U, U, and thorium, they generally do not affect the overall dating scheme. The result is that one can obtain three independent estimates of the age of a rock by measuring the lead isotopes and their parent isotopes. Long-term dating based on the U, U, and thorium will be discussed briefly here; dating based on some of the shorter-lived intermediate isotopes is discussed later.
The uranium-lead system in its simpler forms, using U, U, and thorium, has proved to be less reliable than many of the other dating systems. This is because both uranium and lead are less easily retained in many of the minerals in which they are found. Yet the fact that there are three dating systems all in one allows scientists to easily determine whether the system has been disturbed or not. Using slightly more complicated mathematics, different combinations of the lead isotopes and parent isotopes can be plotted in such a way as to.
One of these techniques is called the lead-lead technique because it determines the ages from the lead isotopes alone. Some of these techniques allow scientists to chart at what points in time metamorphic heating events have occurred, which is also of significant interest to geologists. The Age of the Earth. We now turn our attention to what the dating systems tell us about the age of the Earth.
The most obvious constraint is the age of the oldest rocks. These have been dated at up to about four billion years. But actually only a very small portion of the Earth 's rocks are that old. From satellite data and other measurements we know that the Earth's surface is constantly rearranging itself little by little as Earth quakes occur. Such rearranging cannot occur without some of the Earth's surface disappearing under other parts of the Earth's surface, re-melting some of the rock.
So it appears that none of the rocks have survived from the creation of the Earth without undergoing remelting, metamorphism, or erosion, and all we can say--from this line of evidence--is that the Earth appears to be at least as old as the four billion year old rocks. When scientists began systematically dating meteorites they learned a very interesting thing: These meteorites are chips off the asteroids.
When the asteroids were formed in space, they cooled relatively quickly some of them may never have gotten very warm , so all of their rocks were formed within a few million years. The asteroids' rocks have not been remelted ever since, so the ages have generally not been disturbed. Meteorites that show evidence of being from the largest asteroids have slightly younger ages. The moon is larger than the largest asteroid. Most of the rocks we have from the moon do not exceed 4.
The samples thought to be the oldest are highly pulverized and difficult to date, though there are a few dates extending all the way to 4. Most scientists think that all the bodies in the solar system were created at about the same time.
Evidence from the uranium, thorium, and lead isotopes links the Earth's age with that of the meteorites. This would make the Earth 4. There is another way to determine the age of the Earth.
If we see an hourglass whose sand has run out, we know that it was turned over longer ago than the time interval it measures. Similarly, if we find that a radioactive parent was once abundant but has since run out, we know that it too was set longer ago than the time interval it measures. There are in fact many, many more parent isotopes than those listed in Table 1.
However, most of them are no longer found naturally on Earth--they have run out. Their half-lives range down to times shorter than we can measure. Every single element has radioisotopes that no longer exist on Earth! Many people are familiar with a chart of the elements Fig. Nuclear chemists and geologists use a different kind of figure to show all of the isotopes. It is called a chart of the nuclides. Figure 7 shows a portion of this chart. It is basically a plot of the number of protons vs.
Recall that an element is defined by how many protons it has. Each element can have a number of different isotopes, that is,. A portion of the chart of the nuclides showing isotopes of argon and potassium, and some of the isotopes of chlorine and calcium.
Isotopes shown in dark green are found in rocks. Isotopes shown in light green have short half-lives, and thus are no longer found in rocks. Short-lived isotopes can be made for nearly every element in the periodic table, but unless replenished by cosmic rays or other radioactive isotopes, they no longer exist in nature. So each element occupies a single row, while different isotopes of that element lie in different columns. For potassium found in nature, the total neutrons plus protons can add up to 39, 40, or Potassium and are stable, but potassium is unstable, giving us the dating methods discussed above.
Besides the stable potassium isotopes and potassium, it is possible to produce a number of other potassium isotopes, but, as shown by the half-lives of these isotopes off to the side, they decay away. Now, if we look at which radioisotopes still exist and which do not, we find a very interesting fact. Nearly all isotopes with half-lives shorter than half a billion years are no longer in existence. For example, although most rocks contain significant amounts of Calcium, the isotope Calcium half-life , years does not exist just as potassium, , , etc.
Just about the only radioisotopes found naturally are those with very long half-lives of close to a billion years or longer, as illustrated in the time line in Fig. The only isotopes present with shorter half-lives are those that have a source constantly replenishing them. Chlorine shown in Fig. In a number of cases there is. Some of these isotopes and their half-lives are given in Table II.
This is conclusive evidence that the solar system was created longer ago than the span of these half lives! On the other hand, the existence in nature of parent isotopes with half lives around a billion years and longer is strong evidence that the Earth was created not longer ago than several billion years.
The Earth is old enough that radioactive isotopes with half-lives less than half a billion years decayed away, but not so old that radioactive isotopes with longer half-lives are gone. This is just like finding hourglasses measuring a long time interval still going, while hourglasses measuring shorter intervals have run out. Years Plutonium 82 million Iodine 16 million Palladium 6. Unlike the radioactive isotopes discussed above, these isotopes are constantly being replenished in small amounts in one of two ways.
As such are given responsibilities relevant to their roles when it comes to conventional weapons;. Also called a "Hazardous Devices Technician", PSBTs are usually members of a Police department, although there are teams formed by fire departments or emergency management agencies.
This school helps them to become knowledgeable in the detection, diagnosis and disposal of hazardous devices. They are further trained to collect evidence in hazardous devices, and present expert witness testimony in court on bombing cases.
Before bombing ranges can be re utilized for other purposes, these ranges must be cleared of all unexploded ordnance. This is usually performed by civilian specialists trained in the field, often with prior military service in explosive ordnance disposal. These technicians use specialized tools for subsurface examination of the sites.
When munitions are found, they safely neutralize them and remove them from the site. In addition to neutralizing munitions or bombs , conducting training and presenting evidence, EOD Technicians and Engineers also respond to other problems.
They also assist specialist police units, raid and entry teams with boobytrap detection and avoidance, and they help in conducting post-blast investigations. The EOD technician's training and experience with bombs make them an integral part of any bombing investigation. Another part of an EOD technician's job involves supporting the government intelligence units.
This involves searching all places that the high ranking government officers or other protected dignitaries travel, stay or visit. Generally, EOD render safe procedures RSP are a type of tradecraft protected from public dissemination in order to limit access and knowledge, depriving the enemy of specific technical procedures used to render safe ordnance or an improvised device. Another reason for keeping tradecraft secret is to hinder the development of new anti-handling devices by their opponents: Many techniques exist for the making safe of a bomb or munition.
Selection of a technique depends on several variables. The greatest variable is the proximity of the munition or device to people or critical facilities. Explosives in remote localities are handled very differently from those in densely populated areas. Contrary to the image portrayed in modern-day movies, the role of the modern Bomb Disposal Operator is to accomplish their task as remotely as possible.
Actually laying hands on a bomb is only done in an extremely life-threatening situation, where the hazards to people and critical structures cannot be reduced. Ammunition Technicians have many tools for remote operations, one of which is the RCV, or remotely controlled vehicle, also known as the " Wheelbarrow ".
Outfitted with cameras, microphones, and sensors for chemical, biological, or nuclear agents, the Wheelbarrow can help the Technician get an excellent idea of what the munition or device is. Many of these robots even have hand-like manipulators in case a door needs to be opened, or a munition or bomb requires handling or moving. Also of great use are items that allow Ammunition technicians to remotely diagnose the innards of a munition or bomb.
These include devices similar to the X-ray used by medical personnel, and high-performance sensors that can detect and help interpret sounds, odors, or even images from within the munition or bomb. Once the technicians determine what the munition or device is, and what state it is in, they will formulate a procedure to disarm it. This may include things as simple as replacing safety features, or as difficult as using high-powered explosive-actuated devices to shear, jam, bind, or remove parts of the item's firing train.
Preferably, this will be accomplished remotely, but there are still circumstances when a robot won't do, and a technician must put themself at risk by personally going near the bomb. The Technician will don a specialized protective suit , using flame and fragmentation-resistant material similar to bulletproof vests. Some suits have advanced features such as internal cooling, amplified hearing, and communications back to the control area. This suit is designed to increase the odds of survival for the Technician should the munition or bomb function while they are near it.
Rarely, the specifics of a munition or bomb will allow the Technician to first remove it from the area. In these cases, a containment vessel is used. Some are shaped like small water tanks, others like large spheres. Using remote methods, the Technician places the item in the container and retires to an uninhabited area to complete the neutralization.
Because of the instability and complexity of modern bombs, this is rarely done. After the munition or bomb has been rendered safe, the Technicians will assist in the removal of the remaining parts so the area can be returned to normal.
All of this, called a Render Safe Procedure, can take a great deal of time. Because of the construction of devices, a waiting period must be taken to ensure that whatever render-safe method was used worked as intended. Another technique is Trepanation, in which a bore is cut into the sidewall of a bomb and the explosive contents are extracted through a combination of steam and acid bath liquification of bomb contents. Although professional EOD personnel have expert knowledge, skills and equipment, they are not immune to misfortune because of the inherent dangers: German EOD experts were notified and attended the scene.
Whilst residents living nearby were being evacuated and the EOD personnel were preparing to disarm the bomb, it detonated , killing three of them and injuring 6 others. The dead and injured each had over 20 years of hands-on experience, and had previously rendered safe between and unexploded bombs. The bomb which killed and injured the EOD personnel was of a particularly dangerous type because it was fitted with a delayed-action chemical fuze , which had become highly unstable after over 65 years under ground.
Portable X-ray systems are used to radiograph the bomb before intervention. The purpose is for example to determine if a chemical charge is present or to check the status of the detonator. High steel thickness require high energy and high power sources. Projected water disruptors use a water-projectile shaped charge to destroy bombs, blasting the device apart and severing any detonating connections faster than any fuse or anti-tampering device on the bomb can react.
One example is the BootBanger, deployed under the rear compartment of cars suspected to be carrying bombs. Pigstick is the British Army term for the waterjet disruptor commonly deployed on the Wheelbarrow remotely operated vehicle against IRA bombs in the s.
It fires a jet of water driven by a propellent charge to disrupt the circuitry of a bomb and disabling it with a low risk of detonation. The modern pigstick is reliable and can be fired many times with minimal maintenance. It is now used worldwide. When the rock is molten hot, it is more liquid in texture, allowing the Argon gas to escape.
If all the gas is driven off, then there should be no Argon left in the rock. Once the rock cools and hardens, it is considered to be a closed system, because any new Ar 40 that is produced by the breakdown of K40 is trapped inside the rock crystal and cannot get out.
So the scientist assumes that he or she is able to measure only that Ar 40 which is produced from K 40 since the rock has cooled.
All the other Ar 40 was forced out of the rock by the heat. By forcing out the naturally occurring Ar 40, the clock of the dating mechanism is reset or set to zero. Later, when we start discussing the K-Ar dating technique from a Creationary perspective, we will see that this reseting of the clock is a major issue. The clock might not always be reset by the heat in the Rock.
There are other factors which might not allow the Argon to coming out of the rock as well. An interesting point to make is that the Potassium-Argon process does not date the age of the rock. What it does, is to tell you how long ago the rock was reset, or set to zero.
In addition, some rocks may have been reheated so that the clock was partially reset or fully reset at a later date. So if there are multiple heatings of the rock, the K-Ar dating process may give the researcher a number that is not what the researcher expects to find. Another issue is atmospheric Argon However, this contamination can easily be accounted for in the calculations.
Since Argon 40 exists in the atmosphere, there is a possibility that rock samples could be contaminated with atmospheric Argon. Because the atmospheric Argon is a mix of three different isotopes of Argon: Since there is more Ar than Ar, the amount of Ar is measured to determine the amount of atmospheric Argon that is inserted in the rock.
So this factor can be used to estimate the amount of Argon 40 that has come into the rock via Atmospheric contamination. In any kind of a historical science, assumptions have to be made in the assessing of historical dates. Because it is assumed that man, for example, has ascended over a long period of time, researchers would automatically want to lengthen the amount of time indicated by the artifacts uncovered in archeological digs.
They are looking for answers that would fit their present model. I am not trying to say that they are falsifying their data. On the contrary they wouldn't need to falsify anything. Historical data can be so inconclusive that a host of positions is possible from almost any set of data that is collected.
Man is thought to have progressed through a long period of prehistory cave man's experience before some sort of civilization is started. Only after civilization begins can we begin to gather some sort of data from the discovery of the artifacts that are found Pieces of pottery, etc.
The artifacts according to today's traditional thinking should be slowly progressing in complexity as it is thought that man is progressing in his abilities and ideas that he uses. If man is thought to have progressed over long periods of time, even within the later civilization phase of his existence, than surely as the artifacts are recovered from archaeological sites, the theories and ideas developed will reflect the scientist's own original thinking. This is how science normally works.
They normally work within a fairly well defined set of theories that have become a paradigm. A paradigm is a theory that is so well accepted that no one seriously questions it. This way of doing science is most prominent when the evidence is fragmentary at best. Assumptions throughout the scientific process are extremely important because they must hold the facts together.
Only when specific data comes that either substantiates or falsifies the previously held assumption, can it be known if the thinking was originally correct. Unfortunately, with fragmentary data, the artifact that might falsify a theory is extremely hard in coming or it could easily be overlooked.
So the problem must be solved by a host of assumptions that will probably never be tested. There is also the danger that good data could be thrown out because it doesn't fit with established thinking. For instance, I am told that there are sometimes found in the same level both "early" forms and "modern" forms of man. Because of what is considered to be an impossibility, the modern forms are assumed to have been examples of intrusions. The modern form is considered to have been buried much later in spite of the fact that the specimens are found in the same level.
The areas of science, which are the most successful, which the public notices, are the amazing discoveries in medicine, biology, space exploration, and the like. These are the areas that deal with the here and now. If an experiment is conducted and the information needed to answer the problem is not forthcoming, then another experiment can be designed to answer the problem. The process can continue until some answer to the problem is understood. The problem is only limited by money, ingenuity, and the technical difficulties that have to be surmounted.
In addition to the above limitations of science, historical science is limited by the fragmentary nature of the artifacts it is able to find. In effect, the accuracy of ideas is limited by the assumptions chosen by the researchers. K-Ar dating is not based on irrefutable data alone. It has as its basis of understanding, various assumptions which concern the conditions of the Earth for hundreds of millions of years. These assumptions were originated within an atmosphere of long age preexisting ideas.
Scientists almost never look for indicators in nature that might speak of a very young age for the world's history. Most scientists do not believe that the short chronology of the Bible has any validity at all and most would consider it counterproductive to pursue such a course of investigation.
If in fact such an answer were found, it would be quickly dismissed. It would be assumed that there was something wrong with the idea or the data, and a new scenario would be sought. Some papers give evidence of presenting filtered data. What is meant by filtered data, is that they only present the data that agrees with evolutionary thinking.
The other data is eliminated. Potassium-argon dating and the Cenozoic mammalian chronology of North America. Am J Sci ; This paper is now considered to be a classic paper. Yet they use biotite in an uncritical manor in other areas where the dates they obtained matched their expectations.
On Page , we can also note: Thus, of some 65 samples collected by M. Skinner, only 10 could be used. Sometimes the whole rock basalt date is reported, but sometimes only a mineral fraction is reported from the basalt, like biotite or sanidine.
Why is it that one type of date is used one time and not at another time, is not discussed in the paper. As Paul Giem notes: Thus one could pick the dates that fit one's expectations and create a very impressive list of dates with close agreement without there being more than a general correlation of most dates with one's expectations. It should be remembered that these researchers are not being dishonest in their actions.
They think of the long age scenario of evolution as being fact. They do not believe that there is any alternative way to look at history. So when the data does not come out right, it is only natural that they assume that there is something wrong with the dates that do not fit the long age viewpoint. However, when they turn around and say that the data supports the evolutionary viewpoint and not the Creationary viewpoint. This is not right! The data does not support long ages.
So, many people try to say something like: But this is not true either, the weight of evidence does not prove anything. We do not have an issue of weight of evidence. Rather, what we have is weight of interpretation! This controversy is not over data. The data can go either way. Very intelligent people believe in the long history of the earth and they have good data to support them. There is no question about it. However, I look at that same data and I come to very different conclusions.
This process is legitimate! There is such a thing as multiple interpretation to the data base. There is no proof for either position. On this web page I want to discuss a possible scenario that would allow K-Ar dates to indicate a short age chronology.
Such a discussion might never be allowed in normal scientific circles because of the assumptions they choose to believe as being true. There is such a strong consensus of opinion on K-Ar dating and other similar topics that deal with the history of the Earth that alternative viewpoints are probably viewed as being counterproductive.
Before we start, lets look at the specific K-Ar dating assumptions. The rate of decay half-life , and the branching ratio, of K have not changed. The material in question lost all its argon at an identifiable time, the reset time.
No argon has been lost since the time the rock was reset, or set to zero. No potassium has been gained or lost since the reset time, except by decay. The ratio of K to total K is constant. The total K, Ar, and Ar in the material in question can all be measured accurately.
Imsges: techniques for dating artifacts
Cosmic rays are very, very high-energy atomic nuclei flying through space. Varve layers can be counted just like tree rings.
Some rocks contain pieces of older rocks within them.
Generally, EOD render safe procedures RSP are a type of tradecraft protected from public dissemination in order to limit access and knowledge, depriving the enemy of specific technical procedures used to techniques for dating artifacts safe ordnance or an improvised device. More importantly, b rocks and hot gaseous plasmas are completely incompatible forms of matter! A continuous count of layers exists back gechniques far asyears. The techniques for dating artifacts can bring the Raman, infrared or x-ray fluorescence spectrometer to the huge painting on the wall of the museum, rather than the painting having to be brought to the lab. Researchers have studied the rates of diffusion of helium from zircons, with the prediction from one study by a young- Earth creationist suggesting that it should be quantitatively retained despite its atomic size.
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