Because, during 1996 when this question was asked, the Sun was at it's minimum of activity so there weren't many sunspot 'storms' to eject particles into space to later produce the aurorae on Earth. This began to change in 1998-1999 when the solar activity 'sunspot' cycle began to reach its maximum level ( ca 2000). Usually, the most intense and most frequent aurora happen during the years just before, and just after sunspot maximum. For the current '23rd cycle', we will get another good dose of auroral activity between 2000-2003 as we head for sunspot minimum in this cycle in 2007.
Copyright 1997 Dr. Sten Odenwald
Return to Ask the Astronomer.