Everything You Need to Know About the Aurora

If you’re a traveler who’s been near the North Pole or the South Pole to some degree, you’ve probably seen a natural display of lights in the Earth’s sky at night, and it’s, without a doubt, a wonder to see.

Let’s try to understand what kind of phenomenon it is.

These lights are the results of disturbances in the magnetosphere, or a region in space, caused by the solar wind. Depending on what pole you’re in, there are two types of these occurrences or auroras. One is the aurora borealis, which is seen in the North Pole, and the other is the aurora australis in the South Pole.

The Sun sends us light, heat, small particles, and energy our way, but the protective magnetic field around the Earth shields us from most of these elements. Though the Sun doesn’t send the exact amount of energy all the time, there’s a constant stream of solar wind and solar storms. In one instance of a solar storm called coronal mass ejection, the Sun delivers a huge bubble of electrically charged gas to a massive degree that can travel through space at excessively high speeds.

As the coronal mass ejection comes toward the Earth, some of the small particles and energy can travel down the magnetic field line at the North Pole and the South Pole, which then interact with the gases in the Earth’s atmosphere, resulting in a beautiful display of lights in the sky. Nitrogen gases glow purple and blue, while Oxygen gases give off red and green light.

Other planets have auroras, too, not just on Earth, as long as they have an atmosphere and magnetic fields. In Jupiter and Saturn, amazing auroras were also seen. Most auroras occur in a band known as “auroral zones,” which are more clearly seen against a dark sky at night. An “auroral oval” is a region that currently displays aurora.

Received credits for coining the aurora borealis in 1619, Galileo named the northern latitudes after the Greek name for the north wind and the Roman goddess of the dawn. The southern lights or aurora australis, which are visible from high southern latitudes in China, Argentina, Antarctica, Australia, and New Zealand, have almost identical features to the aurora borealis.

Many types of auroras have been observed from space, such as the “poleward arcs” stretching sunward across the polar cap, “theta aurora,” and “dayside arcs” near noon, although poorly understood and infrequent. Other interesting effects happen, like the flickering aurora, “black aurora,” and subvisual red arcs. Additionally, an often deep red weak glow was observed around the two polar cups in the field lines separating the ones that close through the Earth from those that are close remotely and swept into the tail.

Most of the lights produced are between 90 to 150 km while extending more than 1,000 km at times above the ground, which was revealed by Carl Stormer and his colleagues using a camera to triangulate more than 12,000 auroras. With the increase in the use of digital cameras that have high enough sensitivity, images of auroras are significantly more common today to a greater degree.

Auroras change with time, as in the night, they progress towards coronas and begin with glows, although they may not reach them and tend to fade in the opposite order. They can change in intensity and appearances at shorter time scales, sometimes so slowly that they are difficult to notice, while other times rapidly down to the sub-second scale. An example of intensity variations over a short period of time is the pulsating auroras, typically within 2 to 20 seconds, which are typically accompanied by decreasing peak emission heights of about 8 km for blue and above-average solar wind speeds over 500 km/s.