Ever wonder why February only got twenty eight days, April, June, September and November only got thirty days, but seven months got thirty one days. I mean couldn’t they have distributed the 365 a little more equitably? I mean every month could have gotten thirty days, but there’s always that straggly little problem with the fact that you can’t evenly divide 365. There’s always something left over.
So. There are several different kinds of months. Who knew? Lunar month was the first, because the ancients could chart the moon’s phases, about 29.53 days. There’s that pesky fraction again. Then the Sidereal month, divided the path of the moon into lunar mansions. The Tropical month had to do with the equinox and the position of the moon and this month was 27 days 7 hours 43 minutes 4.3 seconds. That’s probably why it didn’t last. Too many fractions. The Anomallistic month approximates the moon’s orbit as an ellipse rather than a circle, 27 d 13 h 18 min 33.2 s, but, since the moon’s orbit is not fixed this is a problem, not to mention, more fractions.
The Draconic month, which sounds rather fierce, 27 d 5 h 5 min 35.8 s, has more to do with the plane of the elliptic orbit and gravitational pull, but this is cool, The name “draconic” refers to a mythical dragon, said to live in the nodes and eat the sun or moon during an eclipse. And last is the Synodic month, the average period of the moon’s revolution with respect to the line going the sun and earth and running 29 d 12 h 44 min 2.9 s.
So how do you remember which months are which. This chart on Wikipedia is kinda cool and I don’t know why I didn’t know this before. But, Sigh, I didn’t. Now months, the word, came from the Egyptian God Monthu, was a falcon-god of war, an ancient god, his name meaning nomad, originally a manifestation of the scorching effect of the sun, Ra. So that kinda makes sense. The war god, nomadic, having different names as the sun travels across the sky.