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Aurora Borealis (also called "Northern Lights") and Noctilucent Clouds (abbreviated as "NLC")
are beautiful phenomena that occur far above the daily weather. They may be called "space weather". Aurora is caused by streams of charged particles from the sun entering Earth's atmosphere.
The charged particles collide with oxygen and nitrogen atoms in the ionosphere at altitudes over 100 km. These atoms then emit the usually red and green colored light we see.
The magnetic field of the Earth leads the stream of particles to the poles. A few days after an Earth-directed solar eruption, the Northern Lights can incidentally also be observed closer towards the equator.
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