Earth’s Magnetic Field Essay

Earth’s magnetic field is one of the world’s most complicated features. It started to be observed in 1845 by a scientist named Carl Friedman Gauss (Sarfati). The magnetic field is generated inside of the earth’s core and there are many scientists who still debate over how it was first created. There are also many arguments about the many changes that the field has gone through in it’s existence. These arguments are mostly either for a young-earth model or an old earth model. History of the magnetic filed Earth’s magnetic field is a field of electric current that is conducted from the earth’s solid inner core through the liquid outer core (Richard). The electrical current goes around the earth and through it at the north and south poles. The north pole was first discovered by James Ross in 1831 (nasa.gov). No one visited it again until the early 1900s. â€Å"In 1904, Roald Amundsen found the pole again and discovered that it had moved–at least 50 km since the days of Ross,† (nasa.gov). The north pole continued to move at an average of about 10 kilometers per year in the twentieth century (nasa.gov). More recently scientist Larry Newitt of the Geological Survey of Canada has said that it has been moving an average of 40 kilometers every year (nasa.gov). The past of earth’s magnetic field can be studied by past lava eruptions that have hardened. â€Å"When grains of the common magnetic mineral magnetite in volcanic lava or ash flows cool below its Curie point of 570 °C (1060 °F), the magnetic domains partly align themselves in the direction of the earth’s magnetic field at that time. Once the rock has fully cooled, the magnetite’s alignment is fixed,† (Sarfati). The Curie point of a substance is the temperature at which it loses its magnetism, so the lava must cool below this point before the magnetite can align(Sarfati). Using these records scientists have seen that the earth’s pole have switched several times in the past. What the magnetic field actually does that is beneficial to the earth is deflect cosmic rays. The magnetic currents push them toward the north and south poles. â€Å"The increase could knock out power grids, scramble the communications systems on spacecraft, temporarily widen atmospheric ozone holes, and generate more aurora activity,† (Roach). The effect that these cosmic rays would cause to humans are unknown though some think that they would cause tissue damage much like x-rays (Richard). It also reduces the emission of carbon 14 which makes the earth healthier (Humphreys). Magnetic field reversals Magnetic field reversals occur when the currents of the the outer core of the earth move the electrical current around enough that it actually flips upside down. Many scientists believe that when the poles switch places there is a period of time where the magnetic field does not exist, but the University of California professor Gary Glatzmaier says â€Å"It just gets more complicated,† (nasa.gov). He states that when the poles are reverse there will actually be multiple magnetic poles that appear all around the earth. â€Å"A south magnetic pole might emerge over Africa, for instance, or a north pole over Tahiti,†(nasa.gov). Earth’s magnetic field during a reversal (nasa.gov) Some old earth scientists believe that when poles reverse is caused by a second magnetic field coming into existence with an opposite polarity and it then overpowers the first. This idea works if you assume that the geodynamo model is true because if the current of the liquid metal causes the magnetic field then the currents are can make a new field easily (Richard). Once the first field decays the second takes over. Other old earth scientists believe that when the polarity changes it is just the electrical current being shifted enough by the liquid outer core that it reverses directions completely (nasa.gov). Both of these processes would take large amounts of time and since there is proof that there have been many reversals have occurred in the past, this is what old earth scientists can use as evidence that the earth is old (nasa.gov). Dr. Russell Humphreys accepted that reversals were real, unlike some previous creationists. He proposed that the process of convection could cause the magnetic field to reverse (Humphreys). Most young earth scientists believe that most of the reversals occurred during a global flood which occur in Genesis. Dr. John Baumgardner proposed that the Genesis Flood was caused by the plunging of tectonic plates (Sarfati). This would have made the outer parts of the liquid core to cool rapidly which would have sped up the process of convection. In this model reversals would have occurred once every week or two. The most stunning piece of evidence for this is a very thin layer of lava that was found that most have cooled within a few days weeks and the magnetite of the outside of the layer is aligned in opposite direction as the inside (Sarfati). Origins of the field Scientists that believe in the old-earth model have said that there’s is about 300,000 years in between magnetic field reversals and that each reversal takes around 10,000 years to complete (Roach). The electrical current which makes the field has been said to be generated through convection. The liquid of the outer core which conducts the electrical current is constantly moving (Richard). This movement is caused by the heating of the molten liquid by the inner core which causes it to rise and as soon as the liquid cools it will sink. This process is called convection (Richard). This idea that this process can generate an electric current is called the geodynamo model. Young earth scientists strongly disagree with this. The first point that they make is that the geodynamo model has no significant evidence even after decades of research (Humphreys). One proposed idea is that during creation God made atomic nuclei spin in the same direction (Humphreys). The spin of atomic nuclei creates a tiny magnetic field and if the spin of the atomic nulcei were aligned it would add up to a much larger field. Dr. Russell Humphreys who has a Ph.D. in physics says â€Å"as thermal collisions disoriented the nuclear spins, the laws of electricity predict a startup of an electric current within the core of the earth to sustain the field.† Genesis flood model of earth’s magnetic field decay and reversals (Humphreys) Field fluctuations As stated before, the magnetic field prevents some of the production of carbon 14. This also can be used to see the past of the field. This is a process called radiocarbon dating (Humphreys). Using this scientists have seen that the field has been increasing and decreasing in strength over time. These fluctuations are what most old earth scientists use to say that the current decrease is no more than just a fluctuation and that it is not a steady decrease (Richard). The young earth rebuttal for this again goes back to the Genesis flood. In a summary of Dr. Russell Humphrey’s paper on the magnetic field fluctuations of states that because the liquid of the outer core disrupted the electrical current during the flood there would have been what he called higher-order components (Humphreys). This means that there four poles or eight poles, etc, and these poles would die away faster than the two main poles. â€Å"The higher-order components can have either polarity, the strength of the field would fluctuate up and down, as different components died away at different rates.† If the young earth scientists proposed idea of the exponential decay of the magnetic earth of the field is correct then the earth cannot be more than 10,000 years old (Sarfati). At the rate that the field is currently decreasing, which has been calculated with the formula i = Ie-t/Ï„, the field would have been strong enough to melt the earth if it had been in existence longer than 10,000 years (sarfati). Conclusion Both of these groups of scientists have evidence that supports their main points. The earth’s magnetic field a very complicated system that has been around since the beginning of the earth. There has been much that scientists have learned from it and there are still many things that they have to learn about it.