② Now we know that the formation of aurora is the result of the collision between particles in the upper atmosphere and the solar wind 100-300 km above the ground. The solar wind is a stream of particles (electrons and protons) released by the sun. It runs at a speed of more than 6.5438+0.5 million kilometers per hour and is finally captured by the earth's magnetic field. After entering the earth's magnetic field, these particles move faster and move to the magnetic pole. Particles collide with nitrogen and oxygen atoms in the atmosphere, and the energy of charged particles is transferred to atmospheric molecules, making them glow and forming a gorgeous aurora. The color of the aurora depends on the type of atoms that collide. If the light is blue, purple or red, it should be that nitrogen atoms are collided. If particles collide with oxygen atoms, the aurora is mainly green.

The shape and color of the aurora are ever-changing, showing tent-like, arc-like, ribbon-like, ray-like and cloud-like shapes in the sky, which is dazzling and fascinating to viewers. Aurora often moves in elliptical areas near the earth's magnetic poles, which can extend to Finland, Scandinavia, Canada, the northern United States and Siberia. The size of this oval area depends on the strength and speed of the solar wind. At the peak of solar activity with a period of 1 1 year, this area is the largest.

(4) Aurora will also appear during the day, but it is too strong to be observed by the naked eye. As long as the atmospheric and magnetic conditions are similar to those of the Earth, other planets in the solar system can also produce auroras. Images sent back by the probe show that Saturn also has red aurora in its polar regions. Like the earth, the aurora on Saturn is the product of the solar wind entering Saturn's atmosphere.

⑤ In February 2002, a spectacular aurora appeared over Lautanen, Calques, 250 kilometers from the Arctic Circle in Finland. It was a cold night and the night sky was clear. People looked up and saw a strange green light. When people walk and look for the best observation point, time seems to stop. Everyone is looking up at the sky, which is a rare opportunity not to be missed.

⑥ In this area, from the beginning of September to April of the following year, you can see the aurora for about 200 nights in a year, but you must have several basic viewing conditions: the sky in Wan Li is cloudless, and there is no light that will affect your sight, because the city lights will make people unable to see the aurora with weak brightness. The strongest aurora brightness can rival the appearance of the moon.

⑦ But the aurora will also have a negative impact on our life: it will make the compass fail and the communication satellite run abnormally. 1989, the magnetic storm caused by the sun caused more than 6 million residents in Quebec, Canada to lose power.