The Northern Lights
The aurora borealis, otherwise known as the Northern Lights, is one of the finest sights in nature. It is caused by electrically charged particles emitted by the sun and interacting with the earth's magnetic field. Some particles (chiefly electrons) are accelerated towards the earth and guided towards two zones, one near the north pole, the other near the south pole. Colliding with the upper atmosphere at very great speeds, the particles cause the air to glow in the beautiful colours of the aurora.