Aurora Borealis, often referred as 'Northern Lights' or 'Polar lights' are one of the fascinating things that happens on earth. Ever wonder what causes this phenomenon, where can we see them and when? Let's discuss about this below.
What causes Aurora Borealis: Sun being at the center of our solar system and one of the main reasons for life on our planet plays the main role in creating this magical phenomena. The basic cause of this is the interaction of solar wind with the Earth's magnetosphere. Sun acts as an enormous power-plant, whole energy is created deep inside the core. At the center of the sun the temperature reaches upto 15 million Degree Celsius, along with immense pressure. This massive energy is capable of squeezing the Hydrogen atoms together and form Helium atoms causing a nuclear reaction and resulting in release of energy. This creates magnetic fields inside the sun due to electric currents of charged gas (Plasma), In some cases the strong magnetic fields push themselves outside the surface of the sun, and further creates a 'Solar wind' and some of the travels towards earth. These are observed as mystical things happening in the sky called as Aurora Borealis.
Interesting fact about these solar winds is that, they travel at a speed of 8000 Million Kilometers per hour reaching earth in around 36 hours.
Why these appears at Earth's hemispheres: As we know that our Earth is a huge magnet having a magnetic shield around it. This magnetic field helps in deflecting the debris, harmful rays etc. As the solar wind emitted from sun is coming towards Earth, the magnetic field around earth attracts it towards the poles (i.e., magnetic north and south poles). The particles in solar wind mix with earth's atmosphere resulting in displaying lights and colors.
Where can we see them: The Northern Lights oval, meaning the area with the highest probability of seeing the Lights, covers most of Alaska, northern parts of Canada, the southern half of Greenland, Iceland, northern Norway and the northernmost areas of Sweden and Finland, as well as the western half of the Russian north.