Some of us are looking at the calendar this week and wondering why is Easter on April 1st? …without making a fool of one’s self, of course!
Which also may provoke the question: Why is the day for Easter always flipping around from sometime in late March to late April? What determines it?
Blame it on the Moon. The Full Moon, that is.
The date for Easter Sunday and all the Christian observances for celebrating the death and resurrection of Jesus Christ is a simple formula:
Easter is the first Sunday after the first Full Moon that occurs on or after the Spring Equinox. That means Easter Day cannot be earlier than March 22 or later than April 25.
Says who? So, says the Christian authorities that may go back to the Council of Chalcedon in 451 AD.
Our Easter Sunday 2018 will be on April 1st, yep, April Fool’s Day. The first day of Spring was Tuesday, March 20th. The next Full Moon is Saturday, March 31st, and the next Sunday, April 1st, is Easter Sunday.
Forty days before Easter is the Holy Day of Ash Wednesday, and this year it was February 14. That was the beginning of Lent, a symbol of Jesus’ 40 days of fasting.
Mardi Gras is the last fling of decadence before giving up something for the Lent observance. That’s the idea of “Fat Tuesday,” to be gluttonous before cutting back.
Everything about the Christian Easter season is into the first Full Moon in the Spring. Native American Indians called the Full Moon of March names like the Sap Moon, the Worm Moon and the Crow Moon. April names are also appropriate—Pink Moon (for phlox ground covering), Egg Moon and Sprouting Grass Moon.
The March 31st Full Moon is the second of the month, which also happened twice in January. February, with 28 days, was left without a full phase Moon. That won’t happen again until 2037!
The Moon takes 27.3 days to go around the Earth once, called the ‘synodic period,” but 29.5 days to go from one Full Moon to the next, the “sidereal period.” Why the difference? As the Moon goes around the Earth, the pair also move together part-way around the Sun. The alignment of the Earth between the Sun and Moon takes an extra 2.2 days along its orbit for the Moon to create that straight line.
Why does February have only 28 days and the other 11 months either 30 or 31 days? No one knows for sure, but it goes back to pre-Christian Rome when the calendar was based strictly on the phase of the Moon. In 45 B.C., emperor Julius Caesar reformed the calendar to synchronize it with the Sun rather than the Moon. He added 10 days to the year (which before then had 355 days) and added an extra day to February every four years. This lengthened the year to 365.25 days, which is very close to the actual average day length of 365.2425. That is called the “Julian Calendar.” More than 1,000 years later, extra minutes become days and the seasons were getting out of whack—Spring Equinox creeping into mid-April, for example. Pope Gregory XIII decreed that two weeks be skipped in October 1582, to keep the Winter Solstice in December and not January. But landlords charged a full month’s rent! Today we still live by that “Gregorian Calendar.”
So important is the Moon in our daily lives, and yet we barely realize it. For example, the 12 months are based on the 12 complete Moon cycles in a year.
Indeed, the Moon’s gravity has physical effects on Earth’s oceans and lakes and regulates the habits of many species of animals. It’s 29.5-day cycle of phases is even the rhythm for the female menstrual cycle and other mammals.
More than one-fourth the size of Earth (about 2,000 to 8,000 miles wide), the Moon is a tremendous influence on us, creating a binary planet in physical motions.
The celestial motion of the Moon has been the subject of some of the first recorded drawings by primitive stargazers.
And its predictable pattern was the basis of calendars discovered in ancient Mesopotamia, Egypt and China.
So important in our lives, yet, our closest neighbor doesn’t have a fancy name. Earth’s moon is called Moon.
Though big in our minds, the Moon only occupies one-half degree of the sky—360 Moons would span across the sky from horizon to overhead to horizon. At 240,000 miles away, you can cover it up with an extended thumb.
Use a simple pair of binoculars to look at the Moon, and you’ll be amazed at the detail of craters, mountains and dark seas of frozen lava.
Traveling at 2,100 mph eastward, the Moon moves about 12 degrees a day, or its own diameter an hour. As the Moon moves, so does the line between light and dark—the terminator—where the shadows provide the most detail in binoculars or telescope.
There are a hundred or so named moons in the Sun’s system of planets. But ours is the most important to us, and simply called Moon.
So, put on your Easter Bonnet and enjoy the Moon’s silvery light, a certain welcome sight during the early Spring days of thawing and coming alive again.