麻豆淫院

The Earth's magnetic field plays a big role in protecting people from hazardous radiation and geomagnetic activity that could affect satellite communication and the operation of power grids. And it moves.

Scientists have studied and tracked the motion of the magnetic poles . The historical movement of these poles indicates a change in the global geometry of the Earth's magnetic field. It may even indicate the beginning of a field reversal鈥攁 "flip" between the north and south magnetic poles.

who studies the interaction between the planets and space. While the north magnetic pole moving a little bit isn't a big deal, a reversal could have a big impact on Earth's climate and our modern technology. But these reversals don't happen instantaneously. Instead, they occur over thousands of years.

Magnetic field generation

So how are magnetic fields like the one around Earth generated?

Magnetic fields are generated by . A material that enables charges to easily move in it is . Metal is one example of a conductor鈥攑eople use it to transfer electric currents from one place to the other. The electric current itself is simply negative charges called electrons moving through the metal. This current .

Layers of conducting material can be found in the . Currents of charges move throughout the core, and the liquid iron is also moving and circulating in the core. These movements generate the magnetic field.

Earth isn't the only planet with a magnetic field鈥�gas giant planets like Jupiter have a that generates their magnetic fields.

The inside planets results in two types of fields. Larger motions, such as large-scale rotations with the planet, lead to a symmetric magnetic field with a north and a south pole鈥攕imilar to a toy magnet.

These conducting layers may have some local irregular motions due to or smaller flows that do not follow the large-scale pattern. These irregularities will manifest in some small anomalies in the planet's magnetic field or places where the field deviates from being a perfect dipole field.

These small-scale deviations in the magnetic field can actually in the large-scale field over time and potentially even a complete reversal of the polarity of the dipole field, where the north becomes south and vice versa. The designations of "north" and "south" on the magnetic field refer to their opposite polarities鈥攖hey're not related to geographic north and south.

The Earth's magnetosphere, a protective bubble

The Earth's magnetic field creates a magnetic "bubble" called the above the uppermost part of the atmosphere, .

The magnetosphere plays a major role in protecting people. It shields and deflects damaging, high-energy, , which is created in star explosions and moves constantly through the universe. The magnetosphere also interacts with , which is a flow of magnetized gas sent out from the sun.

The magnetosphere and ionosphere's interaction with magnetized solar wind creates what scientists call . Usually, the solar wind is mild and there's little to no space weather.

However, there are times when the sun sheds large magnetized clouds of gas called into space. If these coronal mass ejections make it to Earth, their interaction with the magnetosphere can generate . Geomagnetic storms , which happen when a stream of energized particles hits the atmosphere and lights up.

During space weather events, there's more hazardous radiation near the Earth. This radiation can and astronauts. Space weather can also damage large conducting systems, such as major pipelines and power grids, by overloading .

Space weather events can also disrupt satellite communication and , which many people rely on.

Field flips

Scientists map and track the overall of the Earth's magnetic field using local measurements of the field's orientation and magnitude and, .

The location of the north magnetic pole by about 600 miles (965 kilometers) since the first measurement was taken in 1831. The migration speed has increased from 10 miles per year to 34 miles per year (16 km to 54 km) in more recent years. This acceleration could indicate the beginning of a field reversal, but scientists really can't tell with less than 200 years of data.

The Earth's magnetic field reverses on time scales that vary between . Scientists can tell how often the magnetic field reverses by in the ocean.

These rocks of the Earth's magnetic field when they are created, so dating these rocks provides a good picture of how the Earth's field has .

Field reversals happen fast from a geologic standpoint, though slow from a human perspective. A reversal usually takes a few thousand years, but during this time the magnetosphere's orientation may shift and to cosmic radiation. These events may in the atmosphere.

Scientists can't tell with confidence when the next field reversal will happen, but we can keep mapping and tracking the movement of Earth's magnetic north.

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