Dear Tom,

Some friends and I saw a vivid aurora borealis display over Chicago shortly after midnight on July 5, 1974, and it was absolutely unforgettable! When was the last time the northern lights were so readily visible over Chicago?

Irene F. Mazur, Chicago

Dear Irene,

The northern lights are visible in Chicago about once every two years. That’s the word from Chicago astronomer Dan Joyce, because ever-increasing light pollution severely hampers the viewing of nature’s spectacular light show here. However, in rural areas away from the city, auroras can be seen at least three or four times a year. The 1974 display was spectacular, bombarding the media and law enforcement with numerous reports of sightings. Joyce noted some other prominent Chicago-visible auroras occurred in the spring of 1983, March 1989, August 2000, and late-fall in 2013.