Rocks were promised the earth instant coup field

People are used to having such large-scale changes as the redrawing of the continents or climate are slow. One generation it is difficult to evaluate them, and sometimes simply overlooked. But here's discovery: a grand event — the reversal of the magnetic poles — perhaps even by the standards of people almost instantly. And such a focus can turn the home planet before our eyes.

Recently, Scott Baugh (Scott Bogue) of the Los Angeles Occidental College (Occidental College) And Jonathan Glen (Jonathan Glen) of the U.S. Geological Survey (US Geological Survey) Studied the ancient igneous rocks in the Battle Mountain (Battle Mountain), Nevada. So American geologists have shown that the inversion of the magnetic field of the planet can be thousands of times faster than expected, scientists until now.

Due to the phenomenon of paleomagnetism, a kind of record of geomagnetic field in the cooling and crystallizing lava, the researchers found that at the time of formation of rocks in the Battle Mountain (and this happened 15 million years ago), the shift of the magnetic poles of the Earth by 53 degrees in just one year.

According to current ideas, the formation of Earth's magnetic field meets the liquid part of its core. But the processes in the nucleus still little understood. In this field, and now researchers continue to discover the grand phenomena like "digestion". The figure shows the inner (red) and external (yellow) core of the Earth, the magnetic field lines (blue), the flow of metals (brown lines) caused by the rotation of the nucleus (black arrow), and the convective flows (light brown arrows) (pictured with Site

In the successful (for current scholars) eruption of the first piece of lava is frozen (remembering the direction of the geomagnetic field), but a year later was again heated up the second ejection of molten stone rocks, overwriting in the upper layer of its own new direction by 53 degrees different from the old.

But, in the current data, the reversal of the magnetic poles is 4-5 thousand years or more. This means that the offset of poles during such events is an average 0.045 degrees per year. But Baugh and Glenn believe — reversal may accomplishes much faster in just four years.

If this hypothesis to impose the first signs that the next change has already begun (it they will be discussed below), we can conclude that we have a chance to catch one of the greatest episodes in the geological history of the planet.

The fact that the Earth's magnetic field may roll in the foreseeable future, the scientists argue for a long time. And this event — not a disaster for the planet, and quite ordinary process, if you look at it from the point of view of geological epochs.

The only question is whether there will be a cataclysm soon by ordinary human standards or before a grand spectacle to wait more than a thousand years. And how many will take the inversion itself — also the subject of debate.

The polarity of the geomagnetic field from the present day to the middle of the Jurassic period (top) and for the last five million years (bottom). Black sections — the polarity corresponding to today, white — the opposite (illustration from the site

The frequency of changing the polarity of the magnetic poles of the planet varied widely in the past. You can only bring about average: Pole turned over every 200-300 thousand years.

However, in the region of 42 million years ago there was a 17 inversions for three million years, and, for example, in the mid-Cretaceous was a very long period without inversions, it lasted from 120 to 83 million years ago. And before he had other long ages without coups.

Because scientists believe that the inversion — the process is quite random and it is impossible to catch a clear pattern. However, the last time the "breaking" of the magnetic poles already happened 780,000 years ago. Simply because you can gently suggest that the planet is getting ready for another such permutation. And then there are a number of indirect signs of the impending change.

North Magnetic Pole headed for Russia: When measuring the rate of its displacement in 2009, scientists were 64 kilometers per year. Meanwhile, in 1970 this rate was 10-15 km / year, and only six years ago — about 60. There is acceleration.

Intensity of the geomagnetic field for 150 years has been reduced by about 10%, and in the last 22 years it has fallen by 1.7% (on average, since different parts of the world the changes are not the same). At the same time increased angle of the cusps — the polar regions of the field where the field lines to the sides.

Bands ovye magnetic anomalies are one indication of reversal of the magnetic field in the past. Poured into the ocean ridges rocks solidify, keeping with the current orientation of the magnetization field. As a result of lithospheric blocks are moving apart frozen streams form parallel stripes of alternating magnetization (illustration from the site

In general, the Earth's magnetosphere in recent years, like the beginning of "flow. " Specialists involved in solar-terrestrial relationships, talk about the possibility of stronger-than-normal magnetic storms and auroras during the peak of solar activity cycle that has just begun.

That's no reason to panic. As is easily seen, the memory of Homo Sapiens inversion has not yet happened, but previously there have been many such events and life on Earth is not interrupted.

However, researchers fear causes a significant weakening of the field accompanying the inversion of the poles. Alas, you can not definitively say whether the field will disappear for a while and just how long it will remain a planet without a magnetic shield.

Example strip magnetic anomalies in the fault zone near Vancouver Island. Color shows breed with normal magnetization (which coincides with the modern field) passes — with the magnetization back. Scale — in millions of years (illustration from the site

However, if you draw an analogy with the change of the magnetic poles of the Sun (and it happens once in 11 years), the total loss of our field should not happen and catastrophic consequences for people and life in general — is not going to happen.

Here, by the way, super-fast change, the alleged Scott and Jonathan, to our advantage. Because so little time we run the risk of being subjected to elevated levels of cosmic rays.

The current drift of the pole at 64 kilometers per year — a rounded 0.6 degrees per year. Compare that to 53 degrees in the new study. However, it is not known — whether it was a brief resurgence in the background of a more peaceful shift (maybe an ancient eruption caught the peak of the inversion process) or a complete reversal of the magnetic "north" and "south" are really at that time was so rapid. This issue — a topic for new research.

The story of the tipping bucket "on time" by the magnetic field is similar to the history of the other discoveries — the arrival of a powerful glaciation in the last ice age in just six months. It prompted the scientists to take a fresh look at how fast the Earth's climate can change from one state to another (picture from the site

Not everyone knows the way that the magnetic north pole of the Earth in a physical sense, is the southern and vice versa. There was a mix-up in this way. When the researchers chose the name for the usual poles of the magnet, they could give them any names, even plus-minus, at least some abstract letters. But by the time people have long used the compass, the arrows which represent the dipole magnets.

And here's the end of them, which indicates to the north, called the north pole of the magnet (in the original sense — trailing to the north), and points to the south — south. But because the magnets are attracted to the opposite pole, it turned out that the Earth's magnetic field south pole (in the physical sense) is located in the north and is called the "magnetic north" and the physical north — south.

I wonder what will happen if the inversion of the earth's field, and the names of the magnetic poles do not change — equity in their names restored.

The figure shows the angle between the axis of rotation of the Earth and the dipole axis and the direction of the field lines (Figure Peter Reid).

Let us return, however, a little bit ago. Geologists say that walking away from their places of poles happened and more impressive. In 1995, researchers analyzed the residual magnetization of the ancient igneous rocks in the Steens Mountain (Steens Mountain) in Oregon and found that the speed of rotation of the magnetic field of the planet during the cooling lava flow reached unimaginable six degrees per day (see the article in Nature).

This is several orders of magnitude greater than the rate of which could reflect a science, not counting, of course, the daily fluctuations in the pole position, caused by the impact of charged particles of the solar wind. That is why many experts disputed the conclusions of the authors of the work.

But now Boag and his friends found a second witness, showing that the rapid upheavals geomagnetic field still possible (article about the study will be released in Geophysical Research Letters). Now it would be good to understand — conventional or exclusive are those instant in geological terms jumping golf inversions.

Source: Membrane

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