Use your own words to summarize the principles of Aurora in 100-200 words.

The Northern Lights are the most magnificent and magical sights that nature presents to us.

② Now we know that the formation of auroras is the result of the collision of upper atmospheric particles 100-300 kilometers above the ground and the solar wind. The solar wind is a stream of particles (electrons and protons) released by the sun, which travels at a speed of more than 1.5 million kilometers per hour and is eventually captured by the Earth's magnetic field. After entering the Earth's magnetic field, these particles accelerate and move toward the magnetic poles. The particles collide with nitrogen and oxygen atoms in the atmosphere, and the energy of the charged particles is transferred to atmospheric molecules, causing them to glow, forming the brilliant aurora. The color of the auroras depends on the type of atom being collided. If the light is blue, violet or red, the collided atoms should be nitrogen atoms. If the particles collide with oxygen atoms, the aurora will appear mainly green.

③The shapes and colors of the auroras are ever-changing, showing various shapes in the sky such as tent-like, arc-like, ribbon-like, ray-like and cloud-like shapes. They are dazzling and fascinate the viewers. Auroras often move in an oval-shaped area near the Earth's magnetic poles and can extend to areas such as Finland, Scandinavia, Canada and the northern United States, as well as Siberia. The size of this elliptical region depends on the strength and speed of the solar wind. This area is the largest during the solar maximum cycle, which occurs every 11 years.

④ Aurora also appears during the day, but due to the strong sunlight, it cannot be observed with the naked eye. As long as the atmospheric and magnetic conditions are similar to those of Earth, other planets in the solar system can also produce auroras. Images sent back by the probe show red auroras also appearing in Saturn's polar regions. Like Earth, auroras on Saturn are the product of solar wind entering the planet's atmosphere.

⑤ In February 2002, an extremely spectacular aurora appeared over Kakslautanen, Finland, 250 kilometers away from the Arctic Circle. It was a cold night, the night sky was clear, people looked up and saw a strange-shaped group of green light. When people are walking and looking for the best observation point, time seems to have stopped. Everyone is looking up at the sky, treating this as a rare opportunity that cannot be missed.

⑥In this area, from early September to April of the following year, the aurora can be seen about 200 nights a year, but several basic viewing conditions must be met: the sky is cloudless, And there is no light that affects the view, because the city lights will make people unable to see the weaker aurora. The most intense auroras are as bright as the moon.

⑦But aurora can also have a negative impact on our lives: it can cause compasses to fail and communication satellites to operate abnormally. In 1989, a geomagnetic storm triggered by the sun caused more than 6 million residents in Quebec, Canada, to suffer power outages.