Our Protective Shield



Earth is a Giant Magnet

Magnetic FieldOur planet’s magnetic field extends tens of thousands of miles into space where it deflects the solar wind away from Earth. The gusty solar wind and CMEs buffet and distort Earth’s magnetosphere, sometimes causing magnetic storms.

Deep within Earth’s core, molten metal circulates, and this creates powerful electric currents. These currents generate Earth's magnetic field, which reaches far out into space.

Magnetic FieldEarth’s magnetic field is like that of a huge bar magnet. There are two poles: north and south. Lines of magnetic force run lengthwise, in long arcs from pole to pole. Compasses line up along this magnetic field, always pointing north and south, toward the poles.

Earth’s magnetic field has had many reversals in the past. Currently the north magnetic pole is close to Earth’s south geographic pole. Sometime in the next 10,000 years, Earth’s magnetic poles may reverse again.

When the solar wind reaches Earth, only a small percentage of the wind’s energy penetrates Earth’s magnetic field region, called the magnetosphere. But the energy that does enter is enough to create the brilliant aurora around Earth’s poles, endanger many of our hi-tech systems, and pose a hazard to astronauts who may someday return to the Moon or even journey to Mars.

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