The Aurora Borealis (Northern Lights) and its counterpart, the Aurora Australis (Southern Lights) are caused by the motion of particles from the Solar Wind along the magnetic field lines of the Earth at the poles.  Ejecta thrown off from the Sun can impact the Earth's Magnetosphere, compressing the field lines on the Sun-ward side, and elongating them on the other.  The particles that compose the ejecta can be funneled onto the poles, since the particles must travel along, while spiraling around, the Earth's magnetic field.  When these particles reach the poles, they can excite atoms and molecules in the upper atmosphere, giving rise to the colorful displays known as aurorae.

    Here are just a few photos of the Aurora Borealis.  They were taken by Dick Hutchinson, an amateur photographer who lives only 48 miles outside the Arctic Circle, in Alaska.

    Note the striated pattern in this image.  What you are seeing is actually the pattern of magnetic field lines around the magnetic north pole!  Cool, huh?