Earth is a Giant Magnet
Our
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.
Earth’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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