Which phenomenon is primarily responsible for auroras near Earth's poles?
Solar wind and magnetic field interaction
Auroras (aurora borealis in the Northern Hemisphere, aurora australis in the Southern) are caused by the interaction between charged particles streaming from the Sun (the solar wind) and the Earth's magnetic field.
The Earth's magnetic field channels these charged particles toward the magnetic poles. There, the particles collide with atoms and molecules of oxygen and nitrogen in the upper atmosphere, exciting them; when these atoms relax back to their ground state, they emit characteristic light — green and red from oxygen, blue and purple from nitrogen.
Earthquakes, lightning and volcanic ash have nothing to do with auroras. Hence the correct answer is solar wind and magnetic field interaction — option (3).
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