THEpolar dawnis a natural physical phenomenon that occurs in the pole regions of the planet and is characterized by the formation of greenish patches in the sky. Auroras are observed at night and occur at the time ofterrestrial ionosphere. When this phenomenon happens in thenorthern hemisphere, it is calledNorthern Lights; if the occurrence is in theSouthern hemisphere, the phenomenon is defined as the aurora australis.
How does Polar Aurora occur
All the time, theSunemits very high energy elementary particles that haveelectric charge. This considerable emission of particles is called solar wind. When they reach the Earth's vicinity, they interact with theterrestrial magnetic field. Any electrically charged particle that moves in a region of magnetic field is subject to amagnetic force, which, in this case, conducts the particles, according to the sign of their electrical charges, to the north or south region of the Earth.
The movement of electrical charges in the atmosphere generates shocks between the particles and oxygen and nitrogen molecules. From that moment on, a phenomenon similar to what happens in
fluorescent lamps. Electrical charges transfer energy to oxygen and nitrogen ions, which forreturn to their ground state, release the acquired energy in the form of light.Occurrence on other planets
Auroras are not phenomena that occur only on Earth. As the phenomenon depends on the magnetic field generated by a planet and the particles emitted by the Sun, its occurrence is noticed on other planets in the Solar System. the dawns of the planetsJupiterandSaturnwere perceived by observations made through theHubble Space Telescope. In 2004, the space probe Mars Express detected the occurrence of an aurora on the planet Mars.
artificial auroras
Auroras can be created from the emission of elementary particles by anuclear explosion. In July 1962, an aurora was created artificially after the nuclear test Starfish Prime, made by the United States of America. The artificial phenomenon occurs in the same way as the natural one. The difference lies in the origin of high energy elementary particles.
Auroras are not just a pretty phenomenon!
If the particles that make up the solar wind were not deflected by the Earth's magnetic field, they could cause a series of disturbances, namely:
Exposure to solar radiation;
Interruption of electrical systems;
Impossibility of communication via satellite;
Interruption of data transfer over the internet;
Interruption of telecommunications means.
With the occurrence of auroras, flight communications in extreme regions of the north and south of the planet, for example, they are harmed due to the interference generated by the presence of particles elementary.
solar storms Intense intensity can maximize the occurrence of polar auroras and damage terrestrial technologies. In September 1859, a solar storm increased the normal amount of emitted particles and made communication via telegraph impossible. On that occasion, the effect was named Carrington Event, named after astronomer Richard Carrington.
It is estimated that, if something similar happened today, the economic impacts would be 20 times greater than those caused by Katrina hurricane.
By Joab Silas
Graduated in Physics
Source: Brazil School - https://brasilescola.uol.com.br/fisica/fisica-das-auroras-polares.htm