In the northern and southern pole, beautiful lights show in the sky, best seen at night. They are colorful and mesmerizing to watch. They are called aurora or polar lights. Auroras were first seen in 1791 in New England. The word Aurora is the name of a Roman goddess of dawn. These are mostly seen in high altitude regions that is around Arctic and Antarctic regions.
There are auroral zones between 10o to 20o from the geomagnetic poles. “Auroral oval” is the name given to the region which displays the aurora. The Aurora that appears in the region near to northern pole are called Aurora Borealis and the Aurora that appears in the region near to southern pole are called Aurora Australis.
how this colorful auroras are formed?
You may wonder to know that the reason behind this beautiful event, which mostly appears at night, is our very own star, The Sun. He is boiling and burning continuously since formation. The temperature of the sun at his surface is 5,505o C. But inside in the core of the sun, the temperature is 15 million degree Celsius. As the temperature fluctuates, some charged particles are thrown out of his outermost surface and travel outwards. The technical term for this is “The Solar Wind”. This wind reaches the earth and the charged particles strike with the atoms in the atmosphere. Because of this, excitation in the energy of the electrons occur and when they are returning to the original energy level, release photons which is the light we see. The earth`s magnetic field diverts these charged particles towards the poles. Hence these phenomena can only be seen in these areas.
How the light is of differnt colors?
Aurora of different colors are seen. Sometime they are green, blue and sometimes they are yellow or violet. The reason for the different colors are the atoms with which the charged particles colloid. Collision with Oxygen molecules caused yellow and green light. Collision with nitrogen caused blue, red and violet colors. the molecular nitrogen gives purple color but the atomic nitrogen gives blue.
Altitude also affects the colors produced. At a height of 150 miles green light will appear and above that red will appear. Blue lights appear up to 60 miles and above that purple and violet colors appear.
These auroras can be seen in other planets also. But the planet must be having its atmosphere and active magnetic field. In our solar system Jupiter, Saturn, Uranus and Neptune experience auroras.
The Aurora borealis is always present. But they can be seen when the sky and air are clear. September-October and March-April are the best time to watch these phenomena. NASA says after 2 days of sun spot activity these lights are brighter.
best places to watch aurora:
Darker the place better you can view the aurora. Choose a place away from light pollution and air pollution. Get a place with a larger view of open sky free of clouds. The places near to the Arctic circle are best. This may include Alaska, Iceland, Greenland Norway, Finland etc.
To capture this beauty you don’t need any expensive camera. A normal camera with a tripod will be more than enough for you. The Aurora Borealis appears and disappears very fast, hence you must be patient and quick enough to take a good picture of this beautiful event.
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