The Northern Lights is the common name for Aurora Borealis. It is an awe-inspiring display of the natural lights when the electrically charged particles from the Sun collide with atoms in the high altitude atmosphere. Apart from the most common pale green and pink, shades of red, yellow, green, blue, and violet have also been reported. The Northern Lights are especially related to Polar Regions; and they occur, as the name suggests, in the Northern Hemisphere. We can’t see these natural lights frequently but yes every other clear night. The name Aurora Borealis is inspired from the Roman Goddess of dawn, Aurora, and from the Greek God of the north wind, Boreas. The origin of the Aurora begins on the surface of the sun when solar activity ejects a cloud of gas. Scientists call this a Coronal Mass Ejection (CME). If one of these reaches Earth, taking about 2 to 3 days, it collides with its magnetic field. This field is invisible; and if you could see its shape, it would make the Earth look like a comet with a long magnetic tail, stretching a million miles behind the Earth in the opposite direction of the Sun. When a CME collides with the magnetic field, it causes complex changes to happen to the magnetic tail region. These changes generate currents of charged particles, which then flow along lines of magnetic force into the Polar Regions. These particles are boosted in energy in the Earth’s upper atmosphere, and when they collide with oxygen and nitrogen atoms, they produce dazzling Northern Lights. Although auroras are beautiful but the invisible flows of particles and magnetism that go on at the same time can damage our electrical power grid and satellites operating in space. This is why scientists are so keen to understand the physics of aurora, so we can predict when our technologies may be affected.
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