Solar activity is suddenly weakening, and yesterday, Thursday, July 17 the daily sunspot number was zero. We had no other zero sunspot days so far this year, none last year or in 2012, and only two in 2011, on January 27 and August 14.

We had 48 days with a sunspot number of zero in 2010 (although Spaceweather.com reports 51 days, and they may be correct), and 260 days with a daily sunspot numbe…

American Radio Relay League | Ham Radio Association and Resources

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