Posted on March 25, 2011  Comments (5)

The Aurora from Terje Sorgjerd on Vimeo.

Norwegian landscape photographer Terje Sorgjerd spent a week capturing one of the biggest aurora borealis shows in recent years. He shot the video in and around Kirkenes and Pas National Park bordering Russia at temperatures around -25 Celsius.

Aurora are caused by the collision of charged particles and the Earth’s magnetic field. Aurora Borealis is Latin for northern lights. An aurora is usually observed at night and typically occurs in the ionosphere. The lights are commonly visible between 60 and 72 degrees north and south latitudes, which place them in a ring just within the Arctic and Antarctic polar circles.

Auroras result from emissions of photons in the Earth’s upper atmosphere, above 80 km (50 miles), from ionized nitrogen atoms regaining an electron, and oxygen and nitrogen atoms returning from an excited state to ground state. They are ionized or excited by the collision of solar wind particles being funneled down and accelerated along the Earth’s magnetic field lines; excitation energy is lost by the emission of a photon of light, or by collision with another atom or molecule. Oxygen emissions give off a green or reddish hue, depending on the amount of energy. Nitrogen emissions give off a blue (if the atom regains and electron after it has been ionized) or red hue (if returning to the ground state from an excited state).

Auroras are associated with the solar wind, a flow of ions continuously flowing outward from the Sun. The Earth’s magnetic field traps these particles, many of which travel toward the poles where they are accelerated toward Earth. Collisions between these ions and atmospheric atoms and molecules cause energy releases in the form of auroras appearing in large circles around the poles. Auroras are more frequent and brighter during the intense phase of the solar cycle when coronal mass ejections increase the intensity of the solar wind.

Related: Magnetic Movie – Solar Eruption – Magnetic Portals Connect Sun and Earth – The Mystery of Empty Space – Looking for Signs of Dark Matter Over Antarctica