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Auroras: The Northern and Southern Lights Explained

Introduction

Auroras, also known as the northern lights (aurora borealis) or the southern lights (aurora australis), are a natural light display that occurs in the sky near the Earth's magnetic poles. They are caused by the interaction of charged particles from the sun with the Earth's magnetic field.

How Auroras Form

Auroras are formed when charged particles from the sun, known as the solar wind, interact with atoms and molecules in the Earth's atmosphere. These particles are deflected by the Earth's magnetic field, causing them to travel along magnetic field lines towards the magnetic poles.

When the particles reach the atmosphere, they collide with atoms and molecules, causing them to become excited. As these atoms and molecules return to their ground state, they release energy in the form of light.

Where Auroras Can Be Seen

Auroras are most commonly seen in the regions around the magnetic poles, known as the auroral ovals. These ovals are located at latitudes between 60 and 75 degrees in both the Northern and Southern Hemispheres.

The best time to see auroras is during winter months, when there is less daylight and the nights are longer. Auroras can also be seen during the summer, but they are more difficult to spot due to the longer days.

What Causes the Colors of Auroras

The colors of auroras depend on the type of atom or molecule that is excited. Oxygen atoms produce green and red auroras, while nitrogen atoms produce blue and purple auroras.

The height at which the aurora occurs also affects its color. Auroras that occur higher in the atmosphere appear greener, while those that occur lower in the atmosphere appear redder.

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