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Earth Magnetic Field - What is Earth Magnetic Field?

We live on a huge magnet! 
Around the earth is a giant magnetic field, just like the magnetic field around a bar magnet.

Do you know what makes the earth magnetic? 

Very deep inside the earth, there's hot molten metal.
The earth is always spinning around very fast, and scientists think this causes electric currents in the molten metal.
These electric currents might create the magnetic field around the earth.
Earth Magnetic Field
Although the earth is round, it has magnetic poles at two ends just like a bar magnet.
Imagine a rod passing through the middle of the earth from north to south.
One end is the north magnetic pole, and the other end is the south magnetic pole.
But the magnetic poles are not in the same places as the North Pole and the South Pole on a geographer's map.
These geographic poles are at true north and true south, which are where the earth's lines of longitude meet. But compasses point to the north and south magnetic poles, which are points in the earth's magnetic field.
The north magnetic pole is in Canada, about 870 miles (1,400 kilometers) from the geographic North Pole. The south magnetic pole is in Antarctica, about 1,710 miles (2,750 kilometers) from the geographic South Pole.

Using the earth magnetism

We use magnetism to send radio signals across long distances.
The earth magnetism helps to trap a layer of electrical particles around the planet. This layer is called the ionosphere. Radio signals can be sent from the ground to bounce off the ionosphere and return to the ground a great distance from where they started.
Sometimes electrically charged particles burst out from dark patches on the sun, called sunspots.
A stream of these particles, called the solar wind, sweeps past the earth. The solar wind interferes with the ionosphere. When this happens, compass needles swing wildly in all directions, and we can't send radio signals across long distances.

Aurora Borealis and Aurora Australis

Beautifully colored lights can sometimes be seen in the night sky near the North and South poles. These lights are called the aurora.
The aurora borealis in the north and the aurora australis in the south appear when particles from the sun hit the top layer of the earth's atmosphere. Some of these particles are trapped by the earth's magnetic field and move toward the planet's magnetic poles.
Aurora Borealis and Aurora Australis
The beautiful northern lights, called aurora borealis, shimmer in the night sky near the North Pole. The lights appear when electrical particles from the sun hit the earth's atmosphere.

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