A Q&A with Expert David DeVorkin

Q. How do scientists predict when northern lights viewing will be the best? 

A. Best viewing depends upon dark and clear skies.  That is the realm of meteorology and weather forecasting.  Predicting when the Sun will emit high-energy particle radiation in a flare that will also be directed toward the Earth is the responsibility of heliophysicists, astronomers, physicists and space scientists who are trying to better understand what produces a major solar flare, and how that flare sends high energy radiuation to the Earth's vicinity, becoming trapped in the Van Allen radiation belts and causing the fluorescence we see that we call the aurorae.

Q. Do you have a good analogy of how the northern lights are created that could be used to help explain the process? 

A. If you are familiar with neon signs - the process causing the red light there is very similar to the aurorae.  This is how: the glass tubes are evacuated of all air, and then a tiny bit of neon gas is put in.  The electrodes at either end of the tube are then energized in an electric circuit (the high energy source from the sun in the analogy), the electric current excites the neon gas (electrons in orbit about the neon nucleus jump to higher orbits by absorbing the energy and then spontaneously fall back down emitting red light energy).  You might also consider this helpful link:  http://cse.ssl.berkeley.edu/SegwayEd/abtauroracathodes.html