The Flip of Earth's Electromagnetic Field: How and Why it Happens
Doubtless you have heard that the world will end on 12.21/2012, according to the Mayan calender. The reason usually given is that the magnetic field around the \Earth is way overdue to reverse itself. So the North pole will be the South pole. This article tells how that happens and why. The likelihood of it happening exactly on 12/21/2012 is as likely as its happening tomorrow.
- Axis Poles and Magnetic Poles
- Good Rays, Bad Rays
- The Wandering Poles
- Why is the Earth a Magnet?
- It's Been a While
- How do Scientists Figure Out All This Stuff?
- Mother Question Has Babies
Axis Poles and Magnetic Poles
We all know that Earth has a North Pole and a South Pole. Actually, we have an overabundance of North and South Poles. Well, two each anyway. The true North and South Poles form the axis on which the Earth spins on its daily 360 degree twirl. The other North and South Poles are called the Magnetic Poles. The magnetic North Pole, a citizen of Canada, is the place where the Earth absorbs electrons. These electrons were emitted from the South Pole area and sent scurrying above the Earth to the North Pole, form our electromagnetic field. The Earth is a magnet. But more importantly, having that magnetic field all around the Earth is a real lifesaver for us.
Good Rays, Bad Rays
Outer space teems with things we cannot see with the naked eye, including rays and waves such as x-rays, gamma rays, ultra-violet rays, electromagnetic waves, etc. While some rays and waves, such as light, can be seen, but most cannot, even with a microscope. We can trust science to know that these rays are there, because we have built machines that depend upon the rays being there, like medical and industrial x-ray machines and scanners, and they seem to work as predicted.
Well, as useful as these rays and waves are, in proper doses and controlled conditions, an excess of them will harm us. Some burns us, some cause cancer, and some give us radiation sickness, and so on. So we need this electromagnetic field surrounding Earth because it deflects most of these harmful rays off into space. Those that reach us help warm us, illuminate our days, help things grow and enrich our lives in many other ways. This invisible shell is but one of many earthly conditions that helps make life on Earth possible.
The Wandering Poles
I have mentioned that the magnetic North Pole is a resident of Canada and has been for as long as we can remember. But soon, possibly within the life spans of some of us, it will immigrate to Russia. That is correct . . . . it moves. It was located near Resolute Bay in 1831 when James Ross discovered it. By 1904, when explorer Roald Amundsen found it again, it had moved 50 km north of where Ross had left it. Recently it was spotted by Larry Newitt of the Geological Survey of Canada, whose job it is to track the magnetic North Pole, about 600 km north of Resolute Bay and moving at about the rate of 40 km per year toward Siberia. So, it not only moves but it has been moving faster in recent years. While Canada’s native son seems to be a bit fickle, there is speculation that, however far it may roam, it will someday return.
Why is the Earth a Magnet?
The instability of the magnetic poles is nothing new. They have always been erratic. That instability in the Earth’s electromagnetic field is a result of the Earth having a solid iron core, surrounded by a liquid (molten iron), surrounded again by a very thick, solid crust. The Earth spins at one fairly constant rate while the inner solid inner core spins at a very slightly slower rate. The molten iron layer must absorb the difference. With the upper layers of the molten core moving faster than the inner layers, the molten iron becomes a vast sea of turbulence that generates electricity. The result is that the Earth is a gigantic dynamo or electric generator, creating an Earth sized magnet. Since the turbulence inside the Earth is erratic, so is the amount and flow of the electricity generated by it. There is evidence that in recent years the electromagnetic field surrounding us has weakened somewhat. Alarmists are tempted to blame this weakening in the magnetic shield for the high rates of cancer in recent generations. But, although these measurements are accurate, two or three generations of human life are but a blink in geophysical time. So there is no way of knowing whether these measurements are mere blips or if they represent a significant deviance from the normal, long term magnetic field fluctuations.
It's Been a While
Furthermore, the electromagnetic field is so unstable that every once in a while (in quantum time) the poles actually switch so that the South Pole becomes the positive end (the end toward which a compass will point) and the north magnetic pole becomes the negative pole. That electromagnetic flip, as it is called, has not occurred in 750,000 years. But we know it occurs at intervals ranging from 5,000 years to 50 million years, with an average of about 300,000 years between flips. Are we overdue? I guess a suitable answer might be, “yes, but don’t hold your breath”. We know also that during a flip (which takes centuries) the magnetic field on the surface of the Earth becomes very unstable. Compasses go haywire for a while on parts of the Earth where breaks occur in the nice south to north flow of electricity.
The Earth’s magnetic field is often disrupted by variations in the solar wind. These variations are caused by huge magnetic solar storms that spew charged particles far out into space. As these particles pass through our magnetic shield they cause turbulences that often result in a spectacular display of northern lights. But these disturbances are generally short lived. Disturbances caused by turbulences within the Earth’s core last much longer.
How do Scientists Figure Out All This Stuff?
What is the evidence that such flips have occurred in the past? In the ongoing process of Earth’s creation, rock from Earth’s mantle is subjected to tremendous pressure and, subsequently, heat. The rock melts into lava and is forced to the surface. As it reaches the surface it hardens again to form igneous rock, such as the granite.
As molten lava cools into igneous rock it forms crystals. Since these still superheated crystals respond to Earth’s electromagnetic forces they tend to align themselves, like a compass needle, to point toward Earth’s magnetic North Pole. However, geologists, digging all over the world, have found that some igneous rocks crystals are not pointing north as they lie in their original positions. In fact, where igneous rocks lie in many layers, representing many millions of years of formation, the crystals of rocks of the uppermost layers, created in the last 750,000 years, will point north. The next layer will point south. Still deeper they will be oriented toward the north again. One possible answer to the question of why these rocks seemed to alternate their crystal orientation every few thousand or million years would be that the Earth’s magnetic field flips occasionally.
In the 1960s, scientists discovered the mid-Atlantic oceanic troughs or rifts that spewed molten lava onto the ocean floor. These troughs ran north – south and, although the lava hardened into igneous rock, it did not make sense that the hardened rock did not build up at the sides of the trough and form a volcanic mountain range. The answer, of course, was that, as the lava hardened into igneous rock, it was forced away from the trough. The whole ocean floor moved. The mantle on the west side of the trough moved toward the Americas and the mantle on the east side moved toward Europe and Africa. Plate tectonics was born. The Earth’s mantle is constantly being born.
Mother Question Has Babies
Typical of new discoveries that solve problems, the discoveries raise more questions than they answer. One of the new questions was this. Why were the crystals of the new igneous rocks, at the mouth of the trough, magnetically oriented toward the North Pole, while rocks further away from the trough, on both sides, had crystals magnetically oriented toward the South Pole? And, why were rocks located even further away from the trough oriented north again? In fact, the rock’s magnetic orientation formed a striped pattern parallel to the trough that alternated their north and south orientations.
Life is fragile, but there were animals living 750,000 years ago, the last time a magnetic flip happened on Earth. There is no evidence that the flip caused a major catastrophe such as the one when a comet struck the Yucatan Peninsula, killing off the dinosaurs. So relax, enjoy the sunsets, the animals, the beautiful land, your family, and whatever else you enjoy, and don’t worry about the flip.