© Steven Sandner
Longwarry Victoria, Australia
Latitude: 38° 9' 37'' S
Longitude: 145° 46' 16'' E
25 June 2015 0531 (Local Time)
Camera direction: towards S
Image P/S code: S.14.3
Image I.D.: 5680
The aurora is a visible manifestation of electrically charged solar particles channelled by the Earth's magnetic field acting on the rarefied gases of the higher atmosphere.
Aurorae are most frequently observed in arcs around the magnetic poles – the “auroral ovals”. In the northern hemisphere, the aurora is known as the “aurora borealis”, or “northern lights”. In the southern hemisphere, the aurora is called the “aurora australis”, or “southern lights”. This picture from Australia shows the aurora australis.
The colour of the aurora is dependent on the particular atmospheric gas that emits the light, the electrical state of the gas and the energy of the solar particles. The brightest and most common auroral light is white with a greenish or greenish-yellow tinge and is emitted by atomic oxygen at around 100 km above the ground. At an altitude of about 150 km, single oxygen atoms produce a diffuse red glow. Pinkish light on the lower fringes of arcs and bands comes from atomic nitrogen as low as about 60 km. Molecular nitrogen emits bluish-purple light at the highest levels.
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