The Great Battle in the Sky – What are Northern Lights?

Leonard Cohen, the legendary Canadian poet and singer once wrote:

There is a crack, a crack in everything…That’s how the light gets in.

While the late singer was not likely thinking of Northern Lights when he wrote this, the song comes handy in explaining the phenomenon of Northern Lights!  Having guided over a dozen Northern Lights tours over the past few years, I find a common theme – almost everyone knows that they will see green lights in the sky – but almost no-one knows who put them there! In short, everyone knows the what, very few know the how!

So while you watch the extraordinary show called Northern Lights – here is what’s happening backstage:

The Author:  The Sun

The Great Ball of Fire up in the sky is not a happy camper. It is continuously spewing out radiation (called Solar Wind) as it spins around itself. This is nasty stuff, full of high energy particles – a few million degrees in temperature – and has the power to destroy everything that comes in its path, and yes, it come speeding down to the earth at over 900 kilometres per second. Luckily our satellites are able to pick up images of this happening, so we actually know when the Sun is mad at us.

Solar Wind

The stage: Earth’s Magnetic Field

Well if the nasty Solar Wind ever reached us, we would burn up instantly (yeah, it’s really bad) – however, Mother Nature likes us and wants us  to survive, so .. enter our saviour – Earths Magnetic Field – which protects us from this radiation. It forms a shield around us, and deflects it out

Earths Magnetic Field

Unfortunately no-one’s perfect, and neither is our magnetic field – it has, what Leonard Cohen would call cracks – scientists prefer holes – that does let in some of the radiation!! These cracks or holes are near the North Pole and South Pole.

The Opening Bell

The opening bell – Once some of the solar radiation enters through these holes, they hit the next line of defence that Mother nature has made for us – the atmosphere – with its gases acting as foot soldiers, platoons after platoons of Nitrogen and Oxygen and all kinds of gases,  ready to take on this invading enemy.    A huge battle ensues – the flares literally “burn” or “light up” our soldiers – but the gases don’t give up! They put up a fight –they use tactics – they move around, they come in large numbers, they come in small groups – think of a battle in one of the History Channel movies – it’s just that!

The audience – YOU

While the solar radiation and the atmospheric gases are in the middle of their fight, you, the lucky audience get to watch the whole battlefield from far away (to be precise, you are about 70 to 80 km away from the battlefield!) – and it looks like this:

Atmospheric Gases

So next time you come with us on our tour of Iceland and we see the Northern Lights, think of yourself as a witness to a huge battle – one that your army (the gases) cannot afford to lose! Luckily for us, they have won it every time! If we hadn’t won this battle I won’t be writing this blog and you won’t be reading it!

by Sameer Londhe, http://www.mapsandstories.com

 

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