what causes the lights to change color in the Arora Borialis?

Answer 1

During periods of sunspot activity, high energy electrons streaming down earth's magnetic lines interact with the various components of the atmosphere. These components are mostly oxygen molecules which at about 60 miles up will produce green, or greenish-white. At very high altitudes, oxygen could be dark red. Nitrogen molecules, again, depending on it's altitude, can produce reds, blues, and violet, when the high energy electrons hit them.

So, to directly answer your question of why does the aurora borialis change color, it depends on which molecules are being bombarded with high energy electrons, and at which altitudes, at any given time. These changes depend on what the sun is doing at any given time. Our sun's behavior is anything but constant and solar storms cause bunches of energetic electrons to hit us in multitudes of patterns.

Right now, research is ongoing at NASA to study these phenomena.

Answer 2

When high energy solar particles such as protons are absorbed in the ionosphere the energy states of molecules are raised. As they return to their normal states they give off radiation in different wavelengths in the visible spectrum producing the northern and southern lights.

Answer 3

Finally! This is EXACTLY what I needed for what I'm writing today. I needed an adult variation of the child's question, "Why is the sky blue?". EEEE ha! Thank you Veeeeery much. Jay's got it above, except, now you need to learn what the electromagnetic spectrum means in relation to vision and how we perceive light and color.

Answer 4

Its just the ionization of the charged particles coupled with the atmospheric density, composition and so on.

We get it where I live in South East Scotland. Sometimes it is really slow but great to see.

Answer 5

Fluctuating electromagnetic field, mainly.