The Magnetic Earth!

Here you will earn about Earth's magnetic field, and how it shields us from solar storms!!

The Magnetosphere: For thousands of years, mariners have used the Earth's magnetic field as a compass to find their way to safe harbor. The Earth's field looks very much like the magnetic field of a common bar magnet. Every square foot of the Earth is pierced by a line of magnetic force, which loops from deep inside the Earth, and far into space, only to return back in a great closed circuit thousands of miles away. If there were no Sun or solar wind, the Earth's magnetic field would extend far beyond the orbit of the moon and millions of kilometers into interplanetary space, in the same shape as a bar magnet field outlined by iron filings. In reality, the action of the solar wind changes this picture rather dramatically. The axis of the field is tilted by about 11 degrees to the axis of rotation of the Earth. No one knows why, but these kinds of tilts are found among the magnetic fields of some of the other planets, too. [ MORE ]

  Watch a Magnetosphere Movie

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Ring Current: Encircling the equatorial region of the Earth, and extending to latitudes nearly as far as the Arctic Circle, are regions of space where powerful flows of particles exist. Since the late 1950s at the dawn of the Space Age, they have been called the Van Allen belts. They were at one time believed to be particles from the solar wind, trapped by the Earth's magnetic field. Like an invisible bottle, particles could enter the bottle but would have a hard time leaving. There are actually two belts which are shaped like two nested donuts centered on the Earth. The inner belt contains 10 million-volt, high-energy protons (the stripped nuclei of hydrogen atoms), and is located between 700 kilometers and 12,000 kilometers from the Earth's surface. The outer belt contains mostly electrons with energies higher than 1 million volts, located between 25,000 and 40,000 kilometers from the Earth's surface. [ MORE]

 Watch a Ring Current Movie

 Look at an Enlarged Picture

The Ionosphere: The Earth's atmosphere knows no true boundary. Even at the orbit of the Space Shuttle, there is still quite a lot of air there. Satellites can easily detect our atmosphere out to 10,000 kilometers from the Earth's surface. The outer atmosphere actually occupies the same region of space as the plasmasphere, the ring current and the van Allen Belts themselves. The Earth's atmosphere is far more complex than a simple onion-layered picture would suggest. These layers exchange gas and energy all the way out into the depths of the invisible magnetosphere, and deep into the atmosphere. One of the most interesting of these atmospheric layers is the ionosphere: A layer of charged particles surrounding the Earth at an altitude of about 100 kilometers. [ MORE ]

 Watch a Ring Current Movie

 Look at an Enlarged Picture

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