I just read about the 19 year metonic moon cycle, that on July 31, 2015 there will be a blue moon, and every 19 years after that, this cycle will place a blue moon on July 31 (2034). But there was a blue moon on July 31, 2004- less than 19 years back. Was the 2004 blue moon special in some way that it was not part of this 19 year cycle? Can you please explain this to me?
I just read about the 19 year metonic moon cycle, that on July 31, 2015 there will be a blue moon, and every 19 years after that, this cycle will place a blue moon on July 31 (2034). But there was a blue moon on July 31, 2004- less than 19 years back. Was the 2004 blue moon special in some way that it was not part of this 19 year cycle? Can you please explain this to me?