Introduction

Auroras, also known as northern and southern polar lights, are natural light displays in the sky, and usually observed at night. They typically occur in the ionosphere. They are also referred to as polar auroras. This is a misnomer however, because they are commonly visible between 65 to 72 degrees north and south latitudes, which place them a ring just within the Arctic and Antarctic circles.
Aurorae do occur deeper inside the polar regions, but these are infrequent and often invisible to the naked eye. An aurora is a natural display of glowing light in the night sky, mainly in zones around the magnetic north and south poles of the Earth and some other planets. Auroras can be spotted throughout the world and on other planets. They are most visible closer to the poles due to the longer periods of darkness and the magnetic field.

Some scientists call this phenomenon aurora polaris. In northern latitudes, it is known as aurora borealis or northern lights, and the southern counterpart is called aurora australis or southern lights. The term aurora borealis combines the name Aurora, the Roman goddess of the dawn, with the word Boreas, the Greek name for north wind. It most often occurs from September to October and from March to April.
The aurora is a glow observed in the night sky, usually in the polar zone. It is also known as "northern lights" or "aurora borealis," which is Latin for "northern dawn" since in Europe especially, it often appears as a reddish glow on the northern horizon as if the sun were rising from an unusual direction. The aurora borealis most often occurs from September to October and March to April. Its southern counterpart "aurora australis," has similar properties, so scientists prefer "aurora polaris".
Low on the horizon it may be noticed a faint glow of greenish light which forms an arch, stretching lazily across the sky. As time passes, additional bands of light form and drift overhead, slowly brightening to form giant curtains in the sky that slowly wave as if a gentle breeze were blowing. Suddenly, the bottom of the curtains brightens with a reddish tint and ripple faster. Blues and purples appear. As the curtains pass directly overhead, bright points of light can be seen that swirl like a pinwheel. The entire sky seems to be full of colour and motion. Then, after several minutes, everything fades into a warm green glow.
Aurora is a luminous glow of the upper atmosphere which is caused by energetic particles that enter the atmosphere from above. This definition differentiates aurora from other forms of airglow, and from sky brightness that is due to reflected or scattered sunlight. Airglow features that have "internal" energy sources are more common than aurora, for example lightening and all associated optical emissions like sprites should not be considered aurora.

By the early Twentieth Century, geoscientists had realized that the aurora was due to emission of light from excited atoms in the uppermost portions of the Earth’s atmosphere.
Officially known in the Northern hemisphere as the aurora borealis, the Northern Lights are natural phenomena featuring beautifully coloured light displays over the Earth.
In 1621, a French scientist, Pierre Gassendi, saw the lights in the north and named after the Roman goddess of dawn, Aurora. He added the word "borealis" for the Roman god of the north wind, Boreas. In the southern hemisphere, they are called aurora australis, meaning "southern." The lights are usually seen after dusk near both poles. Although they look elegant and calm, aurorae are produced from millions of explosions of magnetic energy.
The Aurora Borealis (North) and Aurora Australis (South) have roughly a 2500 mile radius limit from their magnetic poles, although the phenomenon occurs on the perimeter of a more elliptical shape. Aurora does not make any sound but it is a purely visual phenomena.
Aurora is the collective name given to the photons (light) emitted by atoms, molecules and ions that have been excited by energetic charged particles (principally electrons) travelling along magnetic field lines into the Earth's upper atmosphere. Aurora results from the interaction of the solar wind with the Earth's magnetic field.

The Aurora is mesmerizing, dynamic displays of light that appear in the Antarctic skies in winter. They are, in effect, nature's light show; visual poetry penned from the quantum leaps of atmospheric gases. As those who have witnessed the Aurora can attest, few sights can equal the magic and mystery of these luminous sheets of colour undulating in the frigid air of the Antarctic winter.
The aurora has fascinated, and often terrified, humans for thousands of years. From ancient times, tales and narratives about the aurora have been told by polar explorers, adventurers, fur traders, and early settlers.
Also known as the Northern Lights, an Aurora is a beautiful natural phenomenon that often occurs in the polar regions of Earth. It appears as colourful clouds and rays of green and red (and sometimes blue) light that dance across the sky. The aurora borealis and aurora australis (Latin for "northern" and "southern" dawn, respectively) occur in symmetric ovals centred on the northern and southern magnetic poles of Earth.


The aurora is formed when charged particles (electrons and protons) are guided by the Earth's magnetic field into the atmosphere near the poles. When these particles collide with atoms and molecules of the upper atmosphere, primarily oxygen and nitrogen, some of the energy in these collisions is transformed into the visible light that characterizes the aurora.


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Aurora by Menal Salim is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
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