November 3, 2003
A: FROM MENTOR MOLLY WILLIAMS IN MI
Occasionally, the sun emits a spray of particles (called a coronal mass ejection). It can take a couple of days for the particles to travel the distance to the earth, because the ejection is mostly protons * real particles, not light that travels much faster. If the particles hit the earth, they ionize the upper atmosphere and create the aurora (northern lights). Because protons are charged, they are directed toward the north and south poles of the earth, so the northern lights (and there's a southern version, too) usually happen only at high latitudes. But with a really big ejection, the light show can reach mid-latitudes. Recently, there were auroras seen in Texas and Florida.
Here's a really good website for information on what the sun is doing:
http://www.spaceweather.com
There are some very nice pictures of the recent aurora.