Aurora
High energy electrons(plasma) and ions given off by the sun are called solar wind. An aurora occurs when charged particles in the solar wind clash with nitrogen and oxygen in the atmosphere.Valence electrons often gather near the north pole and the south pole where geomagnetism is strongest, so auroras are most easily visible in these polar regions(From south and north 65 degrees to 80 degrees latitude). Moreover, auroras occurs most frequently during the maximal term of a sunspot. The color of aurora is built by the spectrum generated when atmospheric atoms collide with charged particles, and remove molecules. An aurora emits light of different colors depending on the altitude from which light is being emitted and the specific atoms and molecules which have collided. Oxygen emits red light if it is high at a latitude and green if it is low atitude, while nitrogen emits purple or pink light. Auroras are divided into three types the polar light belt-type aurora and polar cap glow aurora appear in polar areas before magnetic storms and while mid-latitude auroras are seen at mid-latitudes during magnetic storms(Because of this, these are sometimes called ."low latitude auroras".). Speaking of auroras, the polar light belt-type is most common. Polar light belt-type auroras are further divided into three types of aurora curtains one looks like a curtain while another is a patchy pulsating aurora that seems to spread dim and dark colors and the third irregular aurora has no clear shape and is spread out thinly. Auroras are classified in this way but each aurora looks different depending on the viewing angle and the field of view. For example,a curtain type aurora looks like a corona from beneath but like a curtain from the side and an arc from a distance. Finally, When you see the earth from space, an aurora looks like a crown around the magnetic pole. So,because the exact aurora you see does not look the same as others, it is an even more valuable experience.
 ↑ curtain type aurora Click to enlarge （Displayed in a separate window） |
 ↑ arcuate type aurora Click to enlarge （Displayed in a separate window） |
What is the origin of the name "aurora"?
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