Friday, January 7, 2011
The magnetic poles of Earth are not fixed on the surface, but wander quite a bit.
The pole in the Northern Hemisphere seems to be moving northwards in geographic latitude by about 10 kilometers per year, but the motion is only an average.
On any given day, it moves erratically by many tens of meters because of changes in the currents inside Earth's core, as well as the influence of electrical currents in the ionosphere, and the changing space environment due to solar storms and winds.
The Earth's Magnetic Field: An Overview
Field variations at disturbed times
As well as the regular daily variation the Earth's magnetic field also exhibits irregular disturbances, and when these are large they are called magnetic storms. These disturbances are caused by interaction of the solar wind, and disturbances therein, with the Earth's magnetic field. The solar wind is a stream of charged particles continuously emitted by the Sun and its pressure on the Earth's magnetic field creates a bounded comet-shaped region surrounding the Earth called the magnetosphere. When there is a disturbance in the solar wind the current systems existing within the magnetosphere are enhanced and cause magnetic disturbances and storms.
The amplitude of magnetic disturbances is larger at high latitudes because of the presence of the oval bands of enhanced currents around each geomagnetic pole called auroral electrojets. Some charged particles get trapped at the boundary of the magnetosphere and, in the polar regions, are accelerated along the magnetic field lines towards the atmosphere and finally colliding with oxygen and nitrogen molecules. These collisions result in sometimes spectacular emissions of mainly red and green light known as aurora borealis at northern latitudes and aurora australis at southern latitudes.
The prevailing conditions in the solar-terrestrial environment which are a consequence of the emission of charged particles from the Sun and their interaction with the Earth's magnetic field, is called space weather.
Although irregular, magnetic disturbances exhibit some patterns in their frequency of occurence. The main pattern is the correlation with the 11-year solar cycle. Another important pattern is the 27-day recurrence of some storms related to the 27-day rotation of the Sun as seen from Earth.
The most severe magnetic storm in recent times occurred in March 1989 and this had a number of serious impacts on technological systems by generating damaging geomagnetically induced currents. In particular, the power transmission system in Quebec, Canada, was shut down for over 9 hours. Other effects such as increased corrosion in pipelines are also likely. This is an example of the Earth's magnetic field being a hazard in the modern world.
When a magnetic storm is underway the Earth's atmosphere expands because of heating, and increases the atmospheric drag on satellites at altitudes below about 1000 km. The orbit of the satellite can be changed and sometimes expensive manoeuvres must be made to compensate. Other effects on satellites are caused by radiation hits which can interfere with onboard computers.
The position of the Magnetic North Pole and its possible influence on the Orientation of Racing Pigeons.
The position of the Magnetic North Pole and its possible influence on the Orientation of Racing Pigeons
It is important to realize that when we talk about the location of the pole, we are referring to an average position. The pole wanders daily in a roughly elliptical path around this average position, and may frequently be as much as 80 km away from this position when the Earth's magnetic field is disturbed.
Why is the Pole Moving?
We now know that the cause of the Earth's magnetic field is complex. We believe that it is produced by electrical currents that originate in the hot, liquid, outer core of the Earth. As a simple analogy, consider an electromagnet, in which we can produce a strong magnetic field by passing an electric current through a coil of wire. In nature, processes are seldom simple. The flow of electric currents in the core is continually changing, so the magnetic field produced by those currents also changes. This means that at the surface of the Earth, both the strength and direction of the magnetic field will vary over the years.
This gradual change is called the secular variation of the magnetic field. The position of the North Magnetic Pole is strongly influenced by the secular variation in its vicinity. For example, if the dip is 90° at a given point this year, that point will be the North Magnetic Pole, by definition. However, because of secular variation, the dip at that point will change to 89°58' in about two years, so it will no longer be the pole. However, at some nearby point, the dip will have increased to 90°, and that point will have become the pole. In this manner, the pole slowly moves across the Arctic.
The more rapid daily motion of the pole around its average position has an entirely different cause.
If we measure the Earth's magnetic field continually, such as is done at a magnetic observatory, we will see that it changes during the course of a day, sometimes slowly, sometimes rapidly. The ultimate cause of these fluctuations is the Sun. The Sun constantly emits charged particles that, on encountering the Earth's magnetic field, cause electric currents to be produced in the upper atmosphere. These electric currents disturb the magnetic field, resulting in a temporary shift in the pole's position. The distance and speed of these displacements will, of course, depend on the nature of the disturbances in the magnetic field, but they are occurring constantly. When scientists try to determine the average position of the pole, they must average out all of these transient wanderings."
How do racing pigeons "average out all these transient wanderings" in determining the location of the pole in their minds to be available as a reference useful for navigating their way home? The secular variation is not expected to present much of a problem to racing pigeons because it happens gradually over a long period of time but a different situation exists with the more rapid daily motion of the pole, especially when the earth's magnetic field is disturbed at which time the pole can move rapidly distances of up to 80 km. This may have dire consequences for our racing pigeons as their point of reference has moved enough to cause them to pass by their home loft.
Consider the eruption of Mount St Helen which disturbed the geomagnetic forces enough to move the pole suddenly causing the birds to "locate" their loft where it is not and thus creating difficulties for them. Many racing pigeon clubs all over North America experienced terrible returns from their organized races on that weekend.
High sunspot numbers resulting in high geomagnetic disturbances and a high K factor will also result in rapid movement of the magnetic pole. A "smash" toss need not necessarily occur when the K-factor (a 3 hourly local index of geomagnetic activity) is high.
It is the unreliability of the position of the magnetic pole which will not inspire confidence regarding the bird's homing ability and consequently lead to poor orientation in years of high solar activity, not necessarily on days of geomagnetic disturbances.
(BINGO: Here is why birds are dropping out of the sky in the last few weeks. Its because of the 50 year solar cycle peak and the 11 year sun spot peak are beginning to happen now in 2011.) Story Reports
On Dec 24, 2010, Scientific American asked "Why is the north magnetic pole racing toward Siberia?" "The North Magnetic Pole (NMP) drifts from year to year as geophysical processes within Earth change. For more than 150 years after Ross's measurement its movement was gradual, generally less than 15 kilometers per year. But then, in the 1990s, it picked up speed in a big way, bolting north–northwest into the Arctic Ocean at more than 55 kilometers per year. If it keeps going it could pass the geographic north pole in a decade or so and carry on toward Siberia.
Flock of dead birds found in TN; pole shift is happening
Birds can 'see' the Earth's magnetic field.
Birds use this magnetic field to migrate.
Birds appear to orientate at dusk, and cryptochromes form their pair of free radicals when "activated" by the blue light typical of dusk."
Birds use the magnetic field to navigate, the field is moving as evidenced by the NMP drift, and now birds are dying, Are the two items related? Seems like they could be.
A biblical response comes from Zephaniah and Hosea. In Hosea 4:3 in advance of a judgment the LORD would soon render, He promised that therefore the land mourns, And everyone who lives in it languishes Along with the beasts of the field and the birds of the sky, And also the fish of the sea disappear." So there is precedent for God taking away what was previously for man's benefit, including the birds and fish.
In Zephaniah 1:2 He said, "I will completely remove all things From the face of the earth," declares the LORD. "I will remove man and beast, I will remove the birds of the sky And the fish of the sea,".
Again we see His warning that GOD will remove fish and birds in advance of a judgment.
This is a strange time. It is almost judgment time. Perhaps Solomon said it best in Ecclesiastes 9:12
"Moreover, man does not know his time: like fish caught in a treacherous net and birds trapped in a snare, so the sons of men are ensnared at an evil time when it suddenly falls on them."
Flocks of dead birds found in TN; pole shift is happening. An explaination.