A solar storm swept the southern skies this week, delighting stargazers, camera shutters and social media users.

The remarkable sight, known as Aurora Australis, was triggered by the first extreme geomagnetic storm in 20 years.

Ethereal colours were splashed throughout the country, due to giant clouds of charged particles from the sun called Coronal Mass Ejections (CME).

Blake Estes, observatory manager of iTelescope at Siding Spring Observatory, said the clouds of material were brought out of the sun’s surface by powerful magnetic fields.

These magnetic fields were so powerful the Bureau of Meteorology posted an alert stating the planet was at a G5, or extreme level of geomagnetic activity – not seen since October of 2003.

The G-scale measures the global geomagnetic activity, which refers to fluctuations in Earth’s magnetic field.

“These magnetic fields twist with enormous amounts of energy and break, almost like twisting a rubber band until it snaps, and it flings all that material out into space,” Mr Estes said.

“This is what causes the Auroras. The charged particles hit the earth's magnetic bubble surrounding us, and most of the particles get deflected away.

“But some of the particles get trapped in the magnetic field lines and funnel in toward the poles where these particles crash into the air, in the uppermost portion of our atmosphere.

“When this happens, the atoms of air become energised and glow as if a neon sign would.”

Mr Estes said the various colours are either different gases, or the same ones in different “energised states”.

“For example, oxygen makes green and red light depending on the energy and altitude, while blue and purple is caused by nitrogen,” he said.

CME’s are also associated with solar flares, however, there is a difference between the two.

A solar flare is a powerful burst of radiation and can have some impact on radio communication and navigation systems.

Mr Estes said solar flares do not usually have an effect on the Earth’s atmosphere.

Due to cloud coverage, those in NSW struggled to see the lights of the aurora with the naked eye.

Nevertheless, the lens of a camera, or phone, saw more than what met the eyes of the majority.

IMAGE: The Aurora Australis pictured over Siding Spring Observatory. Photo courtesy of Blake Estes.