Space Weather on Earth

Space Weather on Earth

Northern Lights 3Aurora Borealis (also known as the northern lights) is an electric display of atmospheric fireworks. Nature’s very own lightshow, a shimmering stream of coloured light that suffuses the night sky, it’s a visually stunning show. Part of the beauty and disappointment of this natural occurrence is its unpredictability. Sometimes an aurora can be a disappointing monochrome of white and other times a dancing show of magical colours. History tells that for the Vikings the haunting appearance of the northern lights was an ethereal reflection of the ghosts of virgins. Many Inuit peoples interpreted the eerie sight as walrus spirits playing with human skulls and the Native American Tlingit of Alaska believed the strange sky visions were dancing spirits of the deceased.

This remarkably sci-fi phenomenon has an equally remarkable sci-fi explanation. It occurs when electrically charged particles, travelling at speeds of up to 1,200km (750 mi) per second on the solar wind, are captured by the earth’s magnetic field. As these particles are drawn down towards the poles they hit the ionosphere and collide with the gasses in the atmosphere. These collisions produce photons – light particles that glow red, green, blue and violet. The result is a shimmering sky show known as the aurora borealis or the northern lights. The light show in the south is known as aurora australis or the southern lights.

Viewing of the Northern lights is best done on a clear crisp evening in the winter, away from the glare of the city lights. This is because at this time of year the nights are long and dark and in the summer the sky in places like Iceland never really gets dark enough to see the aurora. Another tip is, if you are unable to see the stars you are unlikely to see the aurora as it is dimmer than starlight.

The aurora borealis is best viewed in places such as Cold, northern places. The lights occur most often and with greatest intensity in areas known as auroral zones. Seen from space, these appear as oval-shaped rings with each magnetic pole roughly in the centre. Generally, the northern oval hangs over Greenland; Arctic Scandinavia; Siberia; Alaska; Manitoba, the Yukon and the Northwest Territories in Canada. But the shape and location of the oval changes with increased solar activity and it can widen and spread fairly far south, so the northern lights are sometimes clearly visible in Scotland and even, on very rare occasions, as far down as the Mediterranean.

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