Howl At These Factoids
Things which occur rarely are said to happen “once in a blue moon.” A blue moon is the second full moon in one calendar month, and it need not actually appear blue. It happens about every 2.5 years.
A “blood moon” often refers to the way the moon appears during a lunar eclipse, when it passes through Earth’s shadow. The light which illuminates the moon has filtered through our planet’s atmosphere, resulting in a red or brownish-looking moon.
When the moon is both full and closest in its orbit to the Earth, the result is often called a “supermoon,” which is a bit larger and brighter than other full moons.
The full, bright moon which occurs nearest the first day of autumn is sometimes called a “harvest moon” because it previously allowed farmers to harvest large fall crops into the night.
Even though the Earth is much larger and more likely to be hit by meteors, many burn up in our atmosphere or otherwise have their craters erased by erosion, tectonics, or volcano action. The moon has no atmosphere, weather, active volcanoes or tectonics, so its surface is full of impact craters new and old.
It takes the moon about 29.5 days to go around the Earth once, and it takes about 365 days for the Earth to go around the sun. Since 29.5 x 12 = 354, our calendar months are longer than lunar months so as to fit 12 months more equally into a year.
The visible phases of the moon go from right to left in the Northern Hemisphere, but left to right in the Southern Hemisphere.