In this instance, it’s not actually blue, it’s rare. Tomorrow night is the second full moon in the month, a blue moon, something that happens only once every 2.7 years. The last one occurred on 12/21/09. Farmers Almanacdescribes the phenomenon as the third moon in a four-moon season (the last one of those occurred on 11/21/10). An even rarer occurrence is when two blue moons occur in the same year, as happened in January and March of 1999. The next blue moon won’t occur until July 2015.
Surprisingly, I couldn’t find a lot of references specific to blue moon mythology. However, a study published in the British Medical Journal in December 2000 found that one emergency room in Great Britain saw more animal bites on or around full-moon nights. A 2007 study in the Journal of the American Veterinary Medical Association did find that more cats and dogs arrived at the veterinary emergency room at Colorado State University on full-moon nights. Cats had a 23 percent greater chance of requiring an emergency vet visit under a full moon than during other moon phases, while dogs had a 28 percent greater chance. The researchers couldn’t say why the link existed, though it’s possible that the full moon’s brightness means more people are out and about with their pets on those evenings, increasing the risk of injury.
While you’re outside checking out the moon of Friday, look for Cassiopeia (she looks like a big “W”). When she rises in the northeast on Friday, it’ll officially be Cassiopeia season. And if you’re out before dawn, you can still see Jupiter and Venus in the eastern sky.
