Seeing The Northern Lights - The Aurora Borealis

Aurorae is a collective term for the Aurora Borealis and the Aurora Australis, or as they or more commonly known, the northern lights and the southern lights. They are natural light shows high in the atmosphere which are absolutely stunning to watch as they dance in slow motion across the night sky. They can vary in colour greatly, spanning the whole spectrum from red right through to blue and purple with yellow and green aurorae being the most common. They are beautiful and many people go on northern lights holidays to go see the northern lights for themselves.

The Aurora Borealis:

(Source-http://www.freewebs.com/nlbt/Northern%20Lights%20best.jpg)

It is commonly visible between latitudes of 65 and 72 north and south - which is just within the Arctic and Antarctic circles - however it is possible to see anywhere in the world at certain times. For example, on the 29th of October 2003 the Aurora Borealis was visible in the United Kingdom in the largest geomagnetic storm of the previous 20 years. Auroras have also been found on other planets and even some moons.

Aurorae on Jupiter:

(Source-http://hubblesite.org/newscenter/archive/releases/1998/04/)
However this photo is owned by NASA (in public domain)

Rivers of Ice that Plough through Mountains

Glaciers are huge masses of ice which moves over land like a very slow river. They are formed where snow accumulates over many years and through it's own weight is compressed into ice. Glaciers are so special because they aren't just packs of ice sitting at the poles, they move as a river does, flowing down towards sea level, carving valleys as they go. These valleys are stunning, and are usually much larger than river valleys.

Glacial Valley:

(Source-http://www.panoramio.com/photo/2627700)

Glacial valleys, also called glacial troughs, have flatter valley bottoms and are relatively straight compared to river valleys. These valleys have impressive, steep slopes on either side gouged out by the huge erosional forces involved. They are commonly called 'u-shaped valleys'. River valleys are instead called 'v-shaped valleys'.

Despite what you might think, glaciers are found in mountain ranges of every continent on the planet, even Africa (e.g. the Futtwangler Glacier in Tanzania) and Australasia (e.g. the Franz Josef Glacier in New Zealand). They vary greatly in size and some reach over a hundred kilometres long. 

The worlds largest glacier is the Lambert Glacier in East Antartica:

• 400 kilometres long
• 100 kilometres wide
• 2500 metres deep
• At it's fastest point it reaches a speed of 1200 metres per year.

The Supervolcano: The Most Destructive Force on Earth

Supervolcanoes are different from normal volcanoes. They aren't recognisable by a conical shape that you would imagine a volcano to be. These volcanoes form calderas which are huge craters in the ground after previous eruptions, which are so large that they are often only noticeable from the air above.


A supervolcano is the most powerful known destructive force on the planet. Only asteroids or other astronomical events are potentially powerful enough to exceed their magnitude. They have became famous due to Yellowstone National Park Volcano in the USA, so much so that there has even been a whole supervolcano dvd covering Yellowstone Park information.

Yellowstone Supervolcano Caldera: 

(Source-http://earth.imagico.de/view.php?site=yellowstone1)

Eruptions are much more powerful than a normal volcanic eruption as the magma concentrates and builds pressure just beneath the surface (as little as 5km) in massive magma chambers where the dimensions are measured in kilometres - which gives an impression of how big these things are! Normal volcanoes form where magma forces its way up through cracks in the crust along destructive plate boundaries (high energy eruptions) and along constructive boundaries (low energy eruptions), and erupt frequently in geological terms. Supervolcanoes form where this magma is stopped from reaching the surface; it melts the surrounding rock and the chamber grows in size and pressure.

"A supervolcano - a volcano capable of producing a volcanic eruption with ejecta greater than 1000 cubic kilometres. This is thousands of times larger than most historic eruptions."

Once this pressure exceeds what the thin crust can take, it breaks through in with incredible force chucking out insane volumes of ash and magma into the upper atmosphere. This causes a volcanic winter as the ash creates a screen around the Earth bouncing off sunlight, turning days to night and summers to winter. Ash covers the ground killing plants and in turn, the animals through starvation and suffocation. After the eruption, the ground collapses at the site of the eruption into the de-pressurised magma chamber and forms the huge caldera.

Introduction

Well I'm new to the whole blogging thing... but I've wanted to do this for a while and I've finally got round to it!

I'm fascinated by our planet and how us humans affect it, extraordinary landforms that have been created, the weird and wonderful and even more. I hope to bring you articles, quotes, and my own views on all these topics and any others that feel relevant.

I have set up commenting to allow everyone to comment on what I do. Please, if you enjoy it or are interested, just leave a short note saying so and feel free to suggest improvements or possible topics I could research and cover on here, maybe even become a follower of the blog! It'll be appreciated.

Here is a documentary about our planet that really gives a good view as to why I am so interested, and i would like to think that, although it's a bit slow paced, it would inspire many a person to take more of an interest into our planet:

http://www.youtube.com/watch?v=jqxENMKaeCU

Here is the first quote to have a think about:

"Now, toying with our atmosphere, we break the rhythms of the sea, nudging the climate, ignorant of whether we can adapt to the new niche we are creating. It may be an arrogant gamble"

(Great Waters, an Atlantic Passage by Deborah Cramer - Pg 133)

Hope to have some more posts coming soon, and with that some followers!

Please leave a short comment, thanks.

The GeoMessenger