It all because of a simple interaction between the sun and our atmosphere.
An aurora or polar light is a natural showcase of light and colors in our earth's sky. There are two types of aurora; If you are near the northern pole, it is called aurora borealis, if you are near the southern pole, it is called aurora australis. It nothing but simply occurs as a result of our earth trying to protect us from excessive radiations from the sun. But how? Let break it down further.
The Earth's magnetic fields
The sun sends us a lot more than just heat and light; It also sends lots of energy and different kinds of particles our way. The outer space generally is a very dangerous place where lethal radiation is very common, even so, meteoroids, asteroids and many other flying bodies are always in random motion thus, our earth needs to be shielded from the danger of these galactic substance penetrating and destroying our home.
Luckily, our earth is indeed protected by an invisible force we call "magnetic field". But the question is; How does earth generate such a strong magnetic field and what role does it play in shielding us ? Let explain.
The center of our earth is accommodated by a spinning ball of molten Iron called the CORE. The action of this core causes our planet to generate a large and powerful magnetic field which stretches far into space. This magnetic field protects us from harmful radiation and high energy particles emanating from the sun by neutralizing these particles. The region associated by this magnetic field is called the magnetosphere. Let take a look at an example of these dangerous radiations.
Solar flares: An example of these high energy particles are the solar flares. Solar flares are brief sudden eruption of high energy hydrogen gas from the surface of the sun. It can generate energy as much as billions of hydrogen bombs; and explosions in the outer region(or corona) of the sun, which blast billions of tons of matter into space.
When dangerous solar waves, such as solar flares, solar winds, and solar storms from the sun is radiated to the earth, it will not penetrate into the earth because the earth is protected by a magnetic field, so instead, the solar particles which are mainly composed of electrons and protons will travel down the magnetic field lines, at the north and south poles into the earth's atmosphere. Since our earth's atmosphere is composed of gases, what we call ionization will take place between the particles and the atmospheric constituent, and the end point is that it will emit light of various colors and spectrum. These light are called aurora. Oxygen will give off green and red light. Nitrogen glows blue and purple. Unlike rainbows, auroras are not optical phenomena and even though they can only be seen during nightfall, they are actually caused by the sun. They also do not only occur in planet earth. It is also likely to occur in planets that also have magnetic fields and atmospheres.
Another kind of celestial phenomenon is STEVE( Strong Thermal Emission Velocity Enhancement). Although scientist know little about this kind of earth's wonder, it as confirmed that it's certainly not an aurora. Look at the picture below, you probably may have had a glimpse in some tv shows like discover family or so. It always appear as a purple and green ribbon in the sky. Very soon, more research might reveal more about this aurora-like phenomenon, but in the mean time, study has it that it more likely to be related to the ionosphere and current technology developed will help scientist investigate further on the nature of charged particles in the ionosphere.
Hope you enjoyed the post, and are really enlightened on matters relating to the planet we live in. If you have any question, just include it in the comment box below, I will be glad to respond. Subscribe for more post concerning physics and astronomy.
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