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Earth's Magnetic Field
What is the Earth's Magnetic Field?
Earth's
magnetic field, also known as the geomagnetic field, is the magnetic
field that extends from the
Earth's interior out into space.
In
space the earths magnetic field meets the solar wind which is a stream of
charged particles mainly a mixture of materials found in the solar plasma,
composed primarily of ionized hydrogen (electrons and protons) that emanate
from the Sun.
The
magnitude of the Earth's magnetic field at the surface ranges from 25 to
65 microteslas (0.25 to 0.65 gauss).
The
Earth's magnetic field (magnetic dipole) is currently tilted at an angle of
about 10 degrees with respect to Earth's rotational axis.
It
is as if there were a bar
magnet placed at that angle at the
center of the Earth.
The
North geomagnetic pole, would be located near Greenland in the northern
hemisphere, is actually the south pole of the Earth's magnetic field, and the
South geomagnetic pole is the north pole.
Why
is the north pole of the earth actually the south magnetic pole?
The
north pole of a compass points to the North Pole of the Earth. Since unlike
poles attract, this actually means that our north pole is really the south
magnetic pole.
What causes the Earth's Magnetic Field
Earth's
magnetic field is created by the turbulent motion of electrically conductive
fluid, most of which is iron.
However,
since these interactions occur deep within the Earth, measuring and observing
them directly is almost impossible.
Scientists
are pretty sure that the reason Earth has a magnetic field is because its solid
iron core is surrounded by a fluid ocean of hot, liquid metal.
So
while parts of Earth's outer core are too deep for scientists to measure
directly, we can infer movement in the core by observing changes in the
magnetic field.
Why does Earth's Magnet Field Change Direction?
"The
Earth's magnetic field is thought to be generated by fluid motions in the
liquid, outer part of the Earth's core, which is mainly composed of iron.
The
reversal process is not literally 'periodic' as it is on the sun, whose
magnetic field reverses every 11 years. Why is this so?
There
are actually two magnetic fields within the earth --There is also a weaker
field spread around the planet, not positioned along the north-south axis.
The
researchers suggest this weak field is created closer to the surface of Earth's
outer core, while the stronger north-south field is produced throughout the
core, including the deepest parts.
Both
fields are thought to result from the movement of electrons from hot iron
atoms in the convective flow of the core, which is more of a liquid than a
solid.
The
movement of the charged particles through the planet creates a magnetic field
just as the movement of an electric current through a wire does.
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