Hi Kyla,

The northern lights occur when charged particles follow coming from space follow the magnetic field lines at the poles of the Earth down to the atmosphere. The particles interact with the Earth's atmosphere and cause the colors you see (sort of like how Sodium vapor lights work). The different colors result from collisions with different atoms and molecules (like oxygen and nitrogen) in the atmosphere.

Typically auroras (also know as the northern lights and the southern lights) happen near the poles of the Earth and so people in Alaska and parts of Canada see them often. But, the region where particles can reach the atmosphere can move southward depending on changes in the Earth's magnetic field. Under special conditions people as far south as California and Texas can see aurora too.

There is some evidence that aurora were seen very, very long ago (possibly in cavemen paintings and ancient Chinese civilizations). Here's a link about some of the old possible sightings:

http://virtual.finland.fi....asp?intNWSAID=25576

Best,
Christina