People might have seen some beautiful colors and shapes in the night sky and wonder what it is. It is aurora! Aurora is caused due to a massive number of collisions between ions, or electrons, and gases that are around the Earth, such as oxygen and nitrogen gases. During these collisions, energy will be released, causing lights, which is known as aurora. This can be normally observed in the poles, especially Northern poles.
History of Aurora
In 1619, Galileo Galilei, who was an Italian astronomer, discovered aurora. Due to the growing interest, he began to observe this phenomenon and tried to find the cause of it. As a result, he initially thought that auroras occur due to the reflection of the sunlight to the atmosphere, which was a misconception. On the other hand, this misconception was corrected by Kristian Birkeland (picture on the right) in the early 1900s. At that time, he suspected the relationship between the electrons and magnetic fields in the Earth. As a result, he did the “terrella experiment”, which is stimulating currents with gases to see any lights or glow that appeared. In the end, he successfully proved it and became the first person who accurately claimed the cause of aurora. Besides them, there are also a considerable number of contributors. For instance, Henry Cavendish particularly utilized triangulation, which is a technique in order to analyze results based on the data that are collected variously, to estimate the altitude where auroras commonly occur.
IMG Credit: https://en.wikipedia.org/wiki/Kristian_Birkeland
Colors of Aurora
Colors of Aurora can be changed depending on the location where the most collision occurs and substances of gases. For example, once the collision excites a considerable number of oxygen atoms, they will emit a green shade, which will result in creating a green aurora. Due to the great abundance of oxygen gas in the atmosphere, this indicates that the most common color of aurora that we can see is normally green.
Fascinating Facts of Aurora
Other planets, such as Jupiter, Saturn, Uranus and Neptune, also have aurora. They all have similar causes except for that of Jupiter. Jupiter particularly has everlasting auroras once the intensity of solar activity increases. In addition, some countries consider aurora as a bad omen, instead of fortune. Before the French revolution happened, there was a record that people saw the ‘blazed red'. As a result, after this circumstance, people began to think of the aurora as the sign of war.
IMG Credit: https://www.nasa.gov/feature/goddard/2016/hubble-captures-vivid-auroras-in-jupiter-s-atmosphere
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