Physics in action! Here's an explanation for why the Northern Lights happen ( http://en.wikipedia.org/wiki/Aurora_(astronomy) ): ***** Auroras result from emissions of photons in the Earth's upper atmosphere (thermosphere), above 80 km (50 miles), from ionized nitrogen atoms regaining an electron, and oxygen and nitrogen atoms returning from an excited state to ground state . They are ionized or excited by the collision of solar wind particles being funneled down and accelerated along the Earth's magnetic field lines; excitation energy is lost by the emission of a photon of light, or by collision with another atom or molecule: oxygen emissions Green or brownish-red, depending on the amount of energy absorbed. nitrogen emissions Blue or red. Blue if the atom regains an electron after it has been ionized. Red if returning to ground state from an excited state . ***** A site that I checked for forecasts http://www.gi.alaska.edu/AuroraForecast . I didn...