The northern lights were visible throughout Alsager last night.
It was a cold day yesterday, reaching only nine degrees celsius, but the sun shone throughout the afternoon.
As evening approached, a rainbow appeared, followed by the sky turning a pink colour.
Not too long afterwards, the aurora borealis began to shimmer over Alsager.
What causes the northern lights?
According to Royal Museums Greenwich, The northern lights are caused by activity on the surface of the sun.
Solar storms on our star’s surface give out huge clouds of electrically charged particles, which can travel millions of miles, and some may eventually collide with the Earth.
Most of these particles are deflected away, but some become captured in the Earth’s magnetic field, accelerating down towards the north and south poles into the atmosphere. This is why aurora activity is concentrated at the magnetic poles.
“These particles then slam into atoms and molecules in the Earth’s atmosphere and essentially heat them up,” explains Royal Observatory astronomer Tom Kerss. “We call this physical process ‘excitation’, but it’s very much like heating a gas and making it glow.”
What we are seeing therefore are atoms and molecules in our atmosphere colliding with particles from the Sun. The aurora’s characteristic wavy patterns and ‘curtains’ of light are caused by the lines of force in the Earth’s magnetic field.
What causes the different colours?
Different gases give off different colours when they are heated. The same process is also taking place in the aurora.
The two primary gases in the Earth’s atmosphere are nitrogen and oxygen, and these elements give off different colours during an aurora display.
The green we see in the aurora is characteristic of oxygen, while hints of purple, blue or pink are caused by nitrogen.
“We sometimes see a wonderful scarlet red colour, and this is caused by very high altitude oxygen interacting with solar particles,” adds astronomer Tom. “This only occurs when the aurora is particularly energetic.”
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