Polar lights or aurora are bright bands of light that streak in the sky of the polar regions. This impressive colour display of polar lights occurs in the dark night skies on north and south poles of Earth. It’s an amazing mystical natural phenomenon occurs on the high latitude magnetic poles region and usually called aurora, a Latin word which means sunrise. Northern Lights or aurora are also known as Aurora Borealis.
How Does Polar Lights/Aurora Occurs?
This natural phenomenon occurs due to the fast moving charge particles in the Earth’s magnetic field. The Sun continuously emits high-energy charge particles towards Earth and when these charge particles also know as solar wind enter into Earth’s magnetic field, they impart their energy to gaseous molecules like oxygen and nitrogen and making them exited and when these gaseous molecules return to their normal state they release energy in the form of lights (photons).
And, when large number of atmospheric particles release photons, they form a kind of visible display in the sky which can easily be seen in dark night but these colour lights are not as light as sun’s light and usually not visible in the day light.
Where Does Polar Lights/Aurora Occurs?
Aurora is not happens in all regions of Earth’s atmosphere but it happened in the high latitude magnetic poles of Earth which are North and South pole regions. When charge particles interacted with Earth’s magnetic field they get deflected around Earth’s magnetic field towards the North and South poles due to magnetic lines of forces and most of the particles energy centred at the poles region which is why aurora occurs at high latitude Earth’s magnetic poles. Magnetic field of Earth protect us from solar wind which would otherwise destroy all life on Earth.
Different gasses in the atmosphere causes different colour in aurora display. And, we mostly see green colour, because our eyes are more sensitive to green colour. Aurora usually occurs about 60 miles or 100 km above Earth’s surface.
When Can Polar Lights/Aurora be Seen?
However, aurora occurs on both magnetic poles of Earth but usually seen in the Northern hemisphere. Aurora in northern region best seen in the winter from September to March in the night sky away from the ground lights. But it occurs in summer too but can’t be seen because summer nights are not enough dark to provide a dark background for aurora display.
Best time to see northern lights is the local mid-night. Northern Lights are best seen in the regions of Norway, Iceland, north Canada, Alaska, north of US, north coast of Siberia and south of Greenland and Southern Lights are visible in south of New Zealand, Australia and Tasmania.
Photo credit: Wikipedia