Earth Science - Other

What is Global Repolarization

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"What is Global Repolarization"
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It is sometimes difficult to sort science fact from superstition, especially when the underlying facts haven't been around long enough to gather superstitions. However, even sorting fact from supposition is hard at times. Such is the case of global re-polarization.

For a long time, we have known that about every 11 years, the sun's north and south poles flip-flop. Not until the last century did scientists honestly believe that the earth does the same thing, though on a much greater time frame. Until there was evidence of the earth changing north and south poles, it wasn’t considered a viable theory.

The evidence came from a curious trait of rocks that solidify after being in a molten state. As they turn solid, iron in the rocks aligns itself to magnetic north, and this is then locked in to the then solid rock. Magnetic poles aren't the same as the true north and south poles, however they are close, so it is then possible to measure the alignment to get an idea of where magnetic north and south were.

This has also been known for some time, but wasn't truly useful until the mid-Atlantic ridge was discovered. This is an area, where magma is continually welling to the surface of the ocean bottom, forcing tectonic plates apart. This has been occurring for a great length of time, possibly millions of years, and as the magma cools and becomes rock, the iron it contains aligns to the north.

The rate of spreading is nearly constant, year after year. This gives science a way to measure the earth's polarity, or where the North Pole was at a given time, simply by taking samples at a growing distance from the ridge and figuring out how long ago the rock must have been turned solid. This is how the curiosity was discovered.

It was found that periodically, bands of rock were laid down, which had magnetic pointers that didn't point north, they pointed south. Except for altering physics, this could most likely only happen if the north and south poles reversed from time to time, as happens on the sun. This doesn't mean that the theory is proven, mind you, only that it is the most likely scenario.

The repolarization occurs at regular intervals, more or less, with each lasting many thousands of years. We know this by measuring the magnetic property of the rocks. From this, we also know that we are overdue for such a flip-flop. This is about the point where the facts end and the suppositions begin, whether they are called superstitions or not.

When the idea was first postulated and given credence from scientific findings, it was supposed that during the switch, the earth dropped its magnetic field. The magnetic field protects the earth from the worst radiation from the sun, so if the field dropped, the result would be catastrophic for all life on the planet.

However, the sun switches poles a little more than every decade, and aside from minor fluctuations in the magnetic field, the lines of force remain in effect. They simply reverse.

In addition, though Earth has had several major extinctions, they don't seem to coincide with the magnetic reversals, and the fact that there have been many between the last mass extinction event, without apparently causing a major disruption of plants and animals on the globe.

Among the things that scientists don't know are how long such a polar reversal will take, what effect, if any, they have on the magnetic field, what problems they may cause for plant and animal life, or even what climate changes might occur. Different scientists have different ideas, but almost all of them are based on supposition. We won't know until it happens and we are here to gather data, and even then, it will take many years to make sense of the data.

Superstitions and suppositions are normal and natural. Our species is driven to ask, "What if?" When we don't have enough data, or the knowledge to use the data we have, we can only answer by guessing. It is at this crossing point where fact becomes superstition. Some of these guesses bear out to be real, and others don't, however it is the natural progression for finding the answers to the questions. It is no different with global repolarization.

More about this author: Rex Trulove

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