Thursday, November 11, 2004

Looking for the aurora -- cont.

The aurora is caused by high energy electrons and protons hurled from the Sun by magnetic storms on its surface. Several days later, this wind of particles slams into the Earth's magnetic field, drawing it out into a long tail that points away from the Sun. The magnetic field in turn snares electrons from the solar wind and pumps them inwards along lines of magnetic influence. Down they dive, near the poles of the Earth, smashing into the rarefied air of the upper atmosphere, causing the atoms of the atmosphere to glow like the gas in a neon tube. On almost any clear, dark night near the Arctic and Antarctic Circles the lights might be seen. Only occasionally, during particularly violent solar storms, does the aurora push down into temperate latitudes.