Nature is full of spectacular phenomena that leave us in awe. One of those phenomena is the Northern lights or aurora borealis.
What are Northern lights?
Northern light is a natural light display in the sky seen from Earth. This colourful natural display is predominantly seen in high-latitude regions mostly around the Arctic and Antarctic. In this phenomenon, dynamic patterns of brilliant lights are displayed in the form of rays, spirals, or dynamic flickers covering the entire sky.
What causes Northern lights?
An aurora or Northern light is created when solar winds from the sun are bombarded into our atmosphere. Solar winds are energised particles expelled by the Sun and travel throughout the solar system.
There are two types of aurora namely aurora borealis (Northern lights) and aurora australis (Southern lights). Both these phenomena occur near the poles.
What causes an aurora?
As mentioned above, it is solar winds from the Sun that are responsible for creating auroras. These energy particles collide with Earth at high speeds but are deflected by the presence of the strong magnetic field of the planet.
However, some of these winds end up getting captured by the magnetic field into the atmosphere and travel to the poles. This results in the formation of an aurora.
The solar winds collide with molecules within the atmosphere, which heats the atoms and causes them to glow. The curtain-like appearance of the lights is due to the lines of force in the Earth’s magnetic field.
Why are auroras so colourful?
The colour of an aurora depends on the chemical composition of the Earth’s atmosphere. Different atoms and molecules like hydrogen, oxygen, and carbon dioxide absorb and radiate a unique set of colours.
Common colours like red and green are produced by nitrogen and oxygen molecules respectively.
Where can auroras be seen?
Auroras can be seen near the Arctic and Antarctic aurora ovals. These are geographical locations where auroras can be seen. Northern lights can be seen in Iceland, Norway, Sweden, Finland, Russia, Canada, Greenland, and Alaska.
Southern lights can be mostly seen from Antarctica. But, residents of Australia living near the southern coast and Tasmania can also see them during intense solar activity.
What time of the year can auroras be seen?
Auroras occur throughout the year. However, they can only be seen when the sky is dark enough. Intense Solar activity during autumn and spring equinoxes, which happen in September and March, can also make it easier to view an aurora.