Aurora Borealis – Northern Lights

Question: Describe about the Article for Aurora Borealis Northern Lights. Answer: The coloured lights display across the night sky in the upper latitudes of the northern hemisphere are referred to as Aurora Borealis. It is imperative to underlying the physics behind these beautiful natural lights. The source of these lights is the solar wind which generates from the sun about 93 million miles away from earth. The solar winds caused in huge solar storms tend to travel huge distances in space and tend to even enter the earths atmosphere. The basic principle of auroras production is ionization of the atoms and molecules present in the magnetosphere (a component of earths atmosphere) caused due to the charged particles present in the solar wind. The excitation of the magnetospheres atoms is caused when the charged particles arising from the solar wind tend to transfer their energies to these on collision. Excitation of atoms implies that the electrons orbiting in the lower state stable energy orbits tend to jump into the higher state unstable energy orbits. However, d ue to lower stability of atoms, the electrons tend to shift to lower energy orbits for enhancing the overall stability and in turn tend to release energy in the form of visible light which is seen as the beautiful auroras. A schematic diagram of the above explanation is as shown below(Imster). In principle, the aurora light is produced by a principle which is used in the production of neon lights. The only major difference being for causing excitation of atoms the energy is provided by external electricity source. In case of aurora, this is achieved through the charged particles of the solar winds which act as natural source(Imster). This ionisation of the constituents of the atmosphere tends to emit various colours of light depending on the exact constituents and energy of the solar wind particles. At different heights, the air would contain different percentages of oxygen and nitrogen which impacts the exact colour of light produced. For instance, high amount of oxygen in the atmospheric air gives rise to red emissions whereas lower proportion of oxygen gives rise to a blue colour due to abundance of nitrogen(Akasofu). The aurora forms that occur in the polar region primarily depend on the underlying acceleration levels that are given to the precipitating particles. The optical emission is usually produced by precipitating protons at higher latitudes unlike proton auroras that are produced at comparatively lower latitudes. These auroras are normally limited to the particular zone called as auroral zone. This particular zone is approximately 3 to 6 degree wide in terms of latitude and 10 to 20 degree wide in terms of longitude. At lower latitudes, this phenomenon is not visible since the earths magnetism deflects these charged particles that are part of the solar wind to the magnetic poles that are concentrated in the polar regions(Savage). Thus, these charged particles of the solar winds do not enter the atmosphere of the lower attitudes which are free of auroras. References Akasofu, Syun-Ichi. Secrets of the Aurora Borealis. New York: Graphic Arts Center Publishing Company, 2002. Imster, Eleanor. What causes the aurora borealis or northern lights? New York, 8 January 2016. Savage, Candace Sherk. Aurora: The Mysterious Northern Lights. San Francisco: Sierra Club Books / Firefly Books, 1994.