The Northern Lights (also called the Aurora Borealis) are a naturally-occurring luminous glow in the upper atmosphere that is visible from Earth under the right conditions.

Streams of energetic charged particles (electrons and protons) originating in the Sun's upper atmosphere (the solar wind) are directed by the Earth's magnetic field into our atmosphere. As this happens, the charged particles collide with oxygen and nitrogen atoms in the upper atmosphere of Earth, releasing light in the process: what you'll see is mostly green light from collisions with oxygen atoms (more common) and red & blue light from collisions with nitrogen atoms (usually seen as purple light on Earth; more rare).

The Earth's magnetic field lines guide the particles and direct them towards the two poles – there's the Northern Lights/Aurora Borealis in the North Pole region and a corresponding Aurora Australis/Southern Lights in the South Pole area. Here's a nice picture from NASA showing the process in action:

The aurora is a continuous phenomenon and it's always on display somewhere on Earth (in the polar regions, as mentioned above). This does not guarantee you'll get to see it.

While an element of luck is involved, you need to know when and where to look to maximize your chances of seeing the elusive natural lightshow. Rest assured, there's a lot you can do to improve your odds and there are very good resources available to help you out. Continue with our next chapter to start planning your Northern Lights adventure: Where? - Best locations to See the Northern Lights.

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