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The Light at the Ends of the Earth

 

For me, Earth Hour is one of the most inspirational events of the year. It’s the world’s largest mass participation event for the environment, bringing together millions of people, businesses and governments to share a common cause and a common sense of purpose – the need to tackle dangerous global climate change.

Supporting WWF’s Earth Hour in Antarctica under the Southern Lights ©Tom Welsh, British Antarctic SurveySupporting WWF’s Earth Hour in Antarctica under the Southern Lights ©Tom Welsh, British Antarctic Survey

Last year, people in 162 countries ‘switched off and had fun in the dark’ to support Earth Hour. This simple, symbolic gesture shows that we really do care about the future of our planet.

But there are some lights that you just wouldn’t want to switch off. The Northern Lights (Aurora Borealis) and the Southern Lights (Aurora Australis) are amongst nature’s most spectacular displays, and I’ve been fortunate to witness them in both polar regions.

Early explorers marveled at them. Inuit, Viking and Maori recounted legends about them, including stories of evil spirits, feasts with the gods or kinsmen trapped in polar ice-caps lighting bonfires as rescue beacons.

So what are these lights that arc across the polar skies, dancing and shimmering, twisting and turning and rolling over themselves? This video goes some way to capturing their wonder and beauty.

In fact, the aurora are caused by solar wind from the sun hitting the magnetic field of the Earth above the poles and producing electrical currents. These currents cause atmospheric gases to glow. Or – to put it another way – it’s a bit like having a massive fluorescent tube flickering above each of the poles!

The Southern lights over Halley Research Station, Antarctica ©, Sam Burrell, British Antarctic Survey The Southern lights over Halley Research Station, Antarctica ©, Sam Burrell, British Antarctic Survey

My top 10 illuminating facts about the Aurora

  1. The Aurora occur in the upper atmosphere and are commonly seen during the night in the polar regions.
  2. The Aurora Borealis  occurs over the Earth’s north geomagnetic pole and the Aurora Australis  occurs over the south geomagnetic pole  – in regions known as ‘auroral ovals’
  3. Occasionally the Aurora Borealis can be seen from here in the south of England, but this takes place only once or twice a decade.
  4. The Aurora Borealis is named after the Roman goddess of the dawn, Aurora, and the Greek term for “wind of the north,” boreas.
  5. Captain James Cook coined the term Aurora Australis following his voyage of discovery to the Antarctic in his ship the Resolution (1772-1775)
  6. Green is the most common colour in the Aurora and is caused by atomic oxygen at altitudes of about 100 and 200kms.
  7. Red is only seen in the Aurora if the atomic oxygen is created above 250 kms
  8. Aurora also occur on other planets, including  Jupiter, Saturn, Uranus and Neptune.
  9. The Aurora on Saturn is only seen in ultraviolet light and can only be observed from space.
  10. Astronauts on board the International Space Station are at roughly the same altitude as the auroras  so they see them from above or side-on!
An aurora dances in the atmosphere on August 20, 2014, as the International Space Station flew over North America. This image was captured by astronaut Reid Wiseman from his vantage point on the ISS. In the upper foreground is a portion of the ISS' robotic arm © NASAAn aurora dances in the atmosphere on August 20, 2014, as the International Space Station flew over North America. This image was captured by astronaut Reid Wiseman from his vantage point on the ISS. In the upper foreground is a portion of the ISS’ robotic arm © NASA

Enjoy Earth Hour wherever you are

Let’s make sure that governments across to world also come together to strike a fair deal on tackling climate change.

A big thanks to British Antarctic Survey for providing images, helping to compile the top 10 facts about Aurora, and supporting Earth Hour in Antarctica.

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