The Arousing Beauty of Aurora by Jayson C. Cruz Jr. Flaring in lucid streaks of hue flapping across the somber sky, the astounding aurora is a natural marvel to behold. Aurora, which is characterized by the appearance of colorful rays of usually green and purple light waves in the sky, is a Latin word used by the astronomer Galileo Galilei to describe this phenomenon denoting "sunrise" or the Roman goddess of dawn. The Naming of the Separated Twins Aurora Aurora is a meteorological light display up at high, visible in the high latitudes of Arctic and Antarctic polar regions. In Arctic region, found on the northern hemisphere, the effect is known as aurora borealis. Whereas aurora autralis, the former’s identical counterpart, is the effect called in Antarctic region which on the other hand is located in southern hemisphere. The terminologies are formed through the addition of a Greek and another Latin words borealis and australis that are coined from "boreas" and "auster" which means north and south winds respectively. These two wonderful events are more otherwise known as the northern and southern lights. But aside from the longitudinal location, there is no other significant difference among these types of aurora. Furthermore, "aurorae" or simply "auroras" is the term used to express its linguistic plurality. The Parents of Aurora The sun is 93 million miles away from Earth but its effects extend far beyond its visible surface. Great storms on the sun send gusts of charged solar particles in the form of solar winds hurtling across space, so if Earth is in the path of the particle stream, its magnetic field and atmosphere react. Then, charged particles from the sun strike atoms and molecules in Earth’s atmosphere, making them in excited state and causing them to light up – aurora is being born. Scientifically, this happened because electrons move to higher-energy orbits, further away from the nucleus; and when an electron moves back to a lower-energy orbit, it releases a particle of light called photon. As discussed by Eleanor Imster (2017), the lead editor of EarthSky.org, this is also similar to what happens in the neon lights on many business signs. Electricity is used to excite the atoms in the neon gas within the glass tubes of a neon sign. That is why these signs give off their brilliant colors. The same principle – but at a far more vast scale – is applied to the aurora as well. The bottom line is that the contact and interaction between solar winds and the magnetosphere (or the region of space surrounding an astronomical object in which charged particles are manipulated or affected by the object’s magnetic field) are the parents of an aurora. The Earthly Visit of Aurora Aurorae may occur in any celestial bodies that has a strong magnetic field and a dense atmosphere just like on the gas giants Jupiter, Saturn, Uranus, Neptune and even on some planets' moons. On the lighter side, our own moon does not have an aurora because it does not have the requisite atmosphere. Here on Earth, Hermann Fritz (1881) and Sophus Tromholt (1881) in more detail, established that most aurorae occur in a band known as the "auroral zone", which is typically 3° to 6° wide in latitude and between 10° and 20° from the geomagnetic poles at all local times (or longitudes), most clearly seen at night against a dark sky. A region that currently displays an aurora is called the "auroral oval", a band displaced towards the night side of the Earth. Auroral activity and aurorae can occur throughout the year, day and night, the best time to view them is at night during the winter months. This is because, during the winter, areas around the North (most of Alaska, northern parts of Canada, the southern half of Greenland, Iceland, Northern Norway, Sweden and Finland) and the South Poles (Antarctica, Chile, Argentina, New Zealand and Australia) have longer periods of darkness. The Elusive-Yet-Fascinating Face of Aurora Depending on the angle where they will be seen from the ground, aurorae can adopt various shapes and produce several fixed patterns. Nevertheless, in accordance with Simon Anders on his 2019 online article "Shapes and Types of Aurora", there are four main auroral patterns which seem to always show up. First on the line is the least structured pattern called "arc". It resembles a uniform rainbow-like spanning from a horizon to another. It can be diffused with pillars but it mostly appears either when the aurora condition is quiet or growing in intensity. Secondly, the "band" that possesses more primary structure and is a ribbon-like pattern exhibiting swirl, fold and snake-like semblances. Similar with the former one, it can be diffused with pillars as well. A "pillar" is another form of aurora usually dubbed as beam or ray. Its occurrence signifies ascension of auroral activity accompanied by an increase in brightness and movement creating huge colored columns of light that soar towards the sky. Therefore, this is the second-most spectacular gem of aurora for many. Last but definitely not the least is the "corona" that probably the most astonishing – the most colorful, fastest-moving and the brightest – yet the rarest auroral form because it appears once in a blue moon. Moreover, in order to appreciate its splendour, it must be positioned overhead of a person as staying true to its term, this will eventually look like a giant luminous crown on top of one's head thus, making it elusive in nature. Consequently, to witness one of it is the ultimate goal of the aurora watchers and chasers. The Vibrant Rouge of Aurora In theory, auroral light may come in any color as long as red, blue, and green are the primary colors of its additive synthesis of hues. Due to low concentration of excited oxygen atoms and lower sensitivity of eyes at these wavelengths, the emission of red and blue or purple auroral lights are only visible under more intense and at the highest levels of solar activities respectively. Thenceforth, scarlet, crimson, and carmine are the most frequently-seen shades of red for the aurorae; others including orange could be seen on rare chances. While green, which atomic oxygen concentration and wavelength's eye sensitivity is normally higher, is the most common color of aurorae followed by the yellow-green ones. Yellow and pink colors could also be seen as they are a mix of red and green or blue (Windows to the Universe). The Strange Voice of Aurora Unlike most of the light-caused natural phenomena, aurora obscurely produces eerie sound. To cut back Andrew Fazekas' disquisition, this sound is similar to a hissing or crackling noise which begins about 70 meters (230 feet) above the Earth's surface and is caused by charged particles in an inversion layer of the atmosphere formed during a cold night (National Geographic, "Auroras Make Weird Noises, and Now We Know Why", 2016). The charged particles discharge when particles from the sun hit the inversion layer, hence creating strokes of sound. In general, aurora is a natural spectacle that offers an entrancing, dramatic and somewhat mysterious display of colorful lights painting the dark skies. It is a result of disturbances in the magnetosphere caused by solar wind. These disturbances are sometimes strong enough to alter the trajectories of charged particles in both solar wind and magnetospheric plasma. These particles, mainly electrons and protons, precipitate into the upper atmosphere (thermosphere or exosphere). The resulting ionization and excitation of atmospheric constituents emit light of varying color and complexity which drive the arousing beauty of aurora.
