Bill Savage, age 17, of Brownsville, Tex., for his question:

WHAT IS A MAGNETIC STORM?

A magnetic storm is a disturbance in the earths magnetic field. These storms are caused by electrically charged particles thrown off from the sun.

During a magnetic storm, compass needles swing unpredictably and radio communications may be disrupted for hours. Pilots and navigators must take special precautions to stay on course.

There are two general types of magnetic storms: great storms and recurrent storms.

Great storms occur after violent eruptions called solar flares on the surface of the sun. During a solar flare, particles are thrown off from the sun into space at up to 2,000 miles per second. Solar flares seem to be associated with groups of sunspots and great storms usually occur about three times a year during maximum sunspot activity.

Recurrent storms are the most frequent type of magnetic storms. They occur about every 27 days. Because 27 days is about the period of rotation of the sun, astronomers believe there may be some connection between these events.