18 Mar 2015

Green sky at night, NZ's delight

8:22 pm on 18 March 2015

An unexpectedly strong geomagnetic storm has hit the earth's atmosphere - lighting up the night sky with colourful aurorae much further from the poles than usual.

A view of the Aurora Australis on the Brighton coast, south of Dunedin, on 17 March 2015.

A view of the Aurora Australis on the Brighton coast, south of Dunedin, on 17 March 2015. Photo: Paul Le Comte

Thousands of people in both hemispheres have been enjoying the celestial display of the Aurora Borealis (Northern Lights) and the Aurora Australis (Southern Lights).

Last night, Twitter was abuzz with residents in the South Island enjoying the technicolour sky, with Otago Museum director Ian Griffin among those to create a timelapse video.

Did you see the lights? Send us your photos and videos to iwitness@radionz.co.nz

The phenomenon is caused by eruptions on the surface of the sun. As explained by the Australian Bureau of Meteorology, the colours appear when electrically charged electrons and protons accelerate down the Earth's magnetic field lines and collide with neutral atoms in the upper atmosphere - usually about 100 kilometres above the Earth.

"These collisions cause the neutral atoms to fluoresce, emitting light at many different wavelengths," it said.

"The most common aurora colours are red and green, caused by the fluorescence of oxygen atoms, while nitrogen atoms can throw bluish-purple lights into the mix."

There have so far been no reports of disruption to satellite communications.

-BBC/ABC