AURORA-THE SHOW BEGINS
Anyone who has ever witnessed an Aurora can never forget the brilliant display. The otherwise bleak night skies, lighting up with an array of psychedelic colors, is truly a visual treat to behold!
What exactly is an Aurora? Where can one see them? How are they formed?
Answers to all these and more, lie hidden in the vast skies of Astronomy, waiting to be revealed.
What is an Aurora?
Aurorais nothing but a natural phenomenon, where lights of various shapes and colors, light up the night sky.
Where can one see them?
Though it can be seen anywhere in the world, these Auroras are an usual sight in the polar region. The Auroras in the Northern pole are called as Aurora Borealis. Those found on the South Pole are called as Aurora Australis.
How are they formed?
The origin of the Auroras is on the solar surface. The Solar winds are emissions of gas, containing free electrons and positive ions. This wind is also called as CME, which is the acronym of coronary mass ejection, where coronary relates to the outer surface of sun-Corona.
The CME is a usual phenomenon, and the speed in normal conditions is about 400 km per second. But whenever there are storms on the solar surface, the speed of the CME accelerates to several times more than the normal speed. These high speed CME collide with the Earth’s magnetic field and the ensuing chemical reaction leads to the emission of a photon. A Photon is basically a light particle.
What are the different shapes seen?
Usually seen as curtains flying in the wind, or may be in the shape of arcs, yet others may be shaped like a wave of light. Sometimes when the ray of light is reflected from a certain single point, the shape of the Aurora may resemble a corona or a crown of light.
The usual orientation of these shapes is in the east west direction.
How are the different colors formed?
The chemical process of collision between the CME and the earth’s magnetic field determines the color of the Aurora.
Blue color- When Nitrogen is emitted during the collision and it regains an electron, blue color is formed.
Red color- When Nitrogen is emitted and it goes back to the inactive state, red color is formed.
Green- When oxygen is emitted very soon within 3 quarter of a second, green color is formed.
Brownish red- When the oxygen emission takes time that is more than 2 minutes, brownish red color is seen.
The difference in the color depends upon the altitude, because the concentration of the gases differs with the various levels and layers of the atmosphere.
Why are they important to us?
Auroras are essentially electromagnetic or geomagnetic phenomenon. These Auroras are capable of producing high electrical impulses, and can easily meddle with the electric fields on the earth. Sudden disrupting of electric power supply occurs due to interference with the power grids.
Telegraph lines have been reported to be affected and rendered totally useless during the occurrence of these Auroras. The extent of disruption recorded was quite significant, being about 125,000 miles of telegraph service lines.
The Auroras have been known to affect the weather, but exact and precise information seems to be missing. Yet it can be firmly said that the occurrence of these Auroras have been found to accelerate the storms originating in the North pacific, as when compared to other times.
The temperature of the air has also been known to be affected by these Auroras. People living in the areas which witness these Auroras often report the air, turning quite chilly and crisper during the Auroras.
Astronomers are trying to deduce methods aimed at predicting the occurrence of these Auroras, in order to gain control over the effects on the earth in a better way.
Tourism and Aurora:
Yellowknifein Canada, in the North West territory has promoted tourism which is based totally on the wonderful Auroras which are a frequent phenomenon here.