Today’s factismal: Countless astronomers and armchair pedants notwithstanding, there is no such thing as a “blue moon”.
If you’ve been watching the news or reading just about any popular science news feed today, then odds are you’ve been told that tonight’s full Moon will be a “Blue Moon”. As is so often the case, that is both true and false.
First the true part: by the definition that NASA and many other astronomical groups use, tonight’s full Moon will be a Blue Moon because it is the second full Moon in a calendar month. And now for the false: the second full Moon in a month is called a blue Moon thanks to a misunderstanding of a Farmer’s Almanac article that used the term for the third moon in an astronomical season with four full Moons. (Getting complicated, isn’t it?) So basically, we have a “rare phenomenon” that is neither rare nor really a phenomenon; it is just a modern description that we use to make something seem more interesting than it really is.
And the sad part is that there are lots of things about the Moon that are more interesting than we think. For example, when you go out to look a the full Moon tonight, take a long gander at the big black splotch that’s looking back at you. That’s Oceanus Procelarum, or the Ocean of Storms. It was named by Giovanni Riccioli, a Catholic priest who liked galileo’s results but not his methods. To “punish” Galileo and his friends for making fun of Church doctrine, he used the names of those who supported the heliocentric universe for the craters nearest Oceanus Procellarum. And it marks one of the largest outflowss of lava anywhere in the Solar System. That big white blotch on the eastern side of the stormy ocean? That’s Copernicus Crater, named for the chief heliocentricist and all-around troublemaker; those long white streaks are bits of lunar rock and dust that were thrown out when the asteroid slammed into the Moon and formed the crater.
If you’d like to learn more about the Moon and maybe even help name a few of the features, why not head over to Moon Zoo? Thanks to today’s we much better telescopes and lunar-orbiting spacecraft, there are lots of high quality pictures of the surface. And you can use those images to identify and name things on the Moon. If you’d like to take part, then head on over to the Moon Zoo: