Thursday, 15 May 2014

Auroras - The Dancing Lights



Auroras

Commonly called The Northern Lights in the northern hemisphere and Southern lights in the southern hemisphere, an aurora is a natural light display in the sky, especially in the Arctic and Antarctic regions in a band known as the auroral zone, which is typically 3° to 6° wide in latitude.


How are Auroras formed?

During large solar explosions and flares,  huge quantities of particles (ions) are thrown out of the sun and into deep space.The ions present in the solar wind are trapped by the magnetic field of the earth and they collide with the atoms and molecules in the atmosphere, releasing energy that is seen as auroras.

The colours of Auroras

The color of the aurora depends on which atom is struck, and the altitude of the meeting.
Green - oxygen, up to 150 miles in altitude
Red - oxygen, above 150 miles in altitude
Blue - nitrogen, up to 60 miles in altitude
Purple/violet - nitrogen, above 60 miles in altitude

Aurora Facts

Green Auroras are the most common.

The lights are at their most frequent in late autumn ( August to November) and winter/early spring ( February / March). 

Magnetic midnight, that occurs about an hour before actual midnight is the best time to spot them.New Moon, Clear, dark sky between 9 PM to 2 AM away from the city lights are ideal, along with a solar maximum.


Types of Auroras


Arc Auroras arc over the night sky like a rainbow



Corona Auroras appear as a crown of diverging rays of light.



Drapery Aurora is the most common and ripple like a curtain.



Diffuse Aurora is the rarest and has a featureless glow.





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