24.2. Earth as a Magnet http://www.ck12.org
Magnet Earth
Imagine a huge bar magnet passing through Earth’s axis, as illustrated inFigure24.10. This is a good representation
of Earth as a magnet. Like a bar magnet, Earth has north and south magnetic poles and a magnetic field.
FIGURE 24.10
Earth is like a giant bar magnet.Earth’s Magnetic Poles
Although a compass always points north, it doesn’t point to Earth’s geographic north pole, which is located at 90°
north latitude (seeFigure24.11). Instead, it points to Earth’s magnetic north pole, which is located at about 80°
north latitude. Earth’s magnetic south pole is also located several degrees of latitude away from the geographic south
pole.
A compass pointer has north and south poles, and its north pole points to Earth’s magnetic north pole. Why does this
happen if opposite poles attract? Why doesn’t the compass needle point south instead? The answer may surprise
you. Earth’s magnetic north pole is actually the south pole of magnet Earth! It’s called the magnetic north pole to
avoid confusion. Because it’s close to the geographic north pole, it would be confusing to call it the magnetic south
pole.
Earth’s Magnetic Field
Like all magnets, Earth has a magnetic field. Earth’s magnetic field is called themagnetosphere. It is a huge region
that extends outward from Earth for several thousand kilometers but is strongest at the poles. You can see the extent
of the magnetosphere inFigure24.12. For an animated version of the magnetosphere, watch the video at this URL: