We all know of the Moon, but it is such a common sight that we have forgotten some of its most important aspects. Every ancient culture used the Moon as the base of their calendar, not the Sun as we do today, and there was great reason to do so.
To understand the importance of the Moon, we first need some facts:
- It takes the Moon 27.5 days to orbit the Earth, but,
- It takes the Moon 29.5 days to cycle though all of its phases (because in the time between the Earth has moved relative to the Sun)
- Because the Moon's orbit is not a perfect circle, those numbers above are not exact. From "Full Moon" to "Full Moon" may be as quick as 28 days or as long as 31.
- The Moon (and Sun) causes the tides. The water level on ocean beaches can change as much as 15 or more metres in some locations. Even lakes can see tides of a few inches.
The calendar we use today to track days, months and years is loosely based on the Sun and Earth's position relative to the Sun. I use the term "loosely based" because if it were truly based on the Sun then the new year would be celebrated at the moment of an Solstice (the point where either the Norther or Southern Hemisphere is maximally exposed to the Sun) or Equinox (the point in time where the North and South Hemispheres are equally exposed). Indeed we do recognize these periods in time, they are the first days of Winter, Summer, Spring and Autumn.
And a reader may question if it is truly a significant difference. Since the first day of Winter is December 21, and the first day of a new year is January 1, one could argue that we do use a true Solar Calendar, just offset by 11 days. However, that is not the case. Many people reading this right now just said to themselves, 'HA! The first day of Winter is December 22, not 21' and they are correct.
When the seasons change, for example from Winter to Spring, you may hear or read something in the news which states, "Spring begins today at 7:46am". Have you ever asked yourself what is so special about 7:46am? The reason there is a time (whatever that time may be) is because that is the exact moment when the alignment of the Sun and the Earth happened such that the tilt of the Earth's equator is exactly parallel to the plane in which Earth orbits (or less technically the exact moment Spring begins).
The important thing to remember is that this is an exact moment in time, and that it is exactly the same moment for the entire Earth. The first moment of Spring (or any season) is the exact same moment for everyone. So it may be 7:46am to you, but for someone in a different time zone it may be 8:46, or even a different day if they live far enough away.
This is where the difference of our calendar and a truly Solar Calendar differ. When New Year's Eve comes around, celebrations are held around the world at different times to celebrate the exact moment of the new year; the new year is not a single moment which the entire Earth celebrates.
In practice this doesn't matter, unless you want to understand the Moon and Lunar Calendars and their importance. In this case it is very important.
A Lunar Calendar is actually a combination of what I called a True Solar Calendar above, and a calendar based on the phase of the moon.
If you want any sort of calendar to track time over periods of years you really do need something based on the Sun. Afterall, you want Summer to be at the same generally time of the year each year. However, instead of basing their calendars only on the Sun, every ancient culture also used the Moon, and we can still see remnants of that today.
For example: Easter is celebrated on the first Sunday after the first Full Moon in the Northern Hemispheres' Spring. The Chinese New Year is celebrated on the second New Moon after the Winter Solstice (or sometimes the 3rd, this is a much more complex calculation involving the Sun as well)
So what is a Lunar Calendar?
In short, it is a calendar based on the seasons (Spring, Summer, Autumn and Winter) and the Moon phase. From full moon to full moon is one month (in fact, you may have heard before that the word Month actually comes from the word Moon, and this is why). This means that sometimes a month is 28 days, sometimes 30, but most of the time it is 29 days but that's not a big deal, even our calendar today has a different number of days each month. It also means that sometimes the "Month" can change at 12:00 midnight one month, but the next month start at 7:46am, because the change of a season is an exact moment in time which happens world wide at the same time. Again, this is not a big deal and you will soon find out why.
So we can now create our Solar Year to be from the exact moment of the start of a season to the beginning of the next, same, season. For example from Winter to Winter, or Summer to Summer, or Spring to Spring, or Autumn to Autumn. It doesn't matter which we choose.
And now the moment we have all been waiting for.... we bring in the Moon. Each season lasts a little more than 91 days and each Moon cycle lasts 29.5 days (on average). Therefore, each season has 3 Moon cycles and thus is 3 months long. And we can name these three full Moons, and so we will name them the Early Full Moon, the Middle Full Moon and the Late Full Moon.
So the question must be asked, why did all these ancient cultures use a Lunar Calendar?
Have you ever watched a nature show on television? Maybe it was about turtles in the ocean? And they say that (for example) the turtles always return to the island they were born on the first full Moon of Spring to lay their eggs?
Or maybe a certain fish which spawns only during the second full Moon in summer?
And this full Moon obsession is not just limited to ocean going creatures. In fact most animals have their breeding, or birth giving, or other lively functions based on the phases of the Moon (and the season; important!). Even plant life follows this plan with many farmers planting crops based on moon phases and not exact dates on calendars.
There are many reasons for this in nature for animal life. For example, coming out of hiding at night to breed or give birth helps to avoid predators, and doing so in a full moon helps them find mates and in the case of the new borns find shelter, parents, the ocean or food. But reason or cause is not important right here and now, only acceptance that this is fact; that all of nature naturally runs on a Lunar calendar, a calendar based on Moon phases and season.
And so, this is importance of a Lunar calendar, and why every ancient culture used the Lunar calendar to keep track of time. Because all of nature uses this calendar ancient man could schedule hunts, harvests, trades and all aspects of their life by it.
..... almost ......
The Blue Moon
Did someone tell you that a blue moon was the 2nd full moon in a month that had 2 full moons? They are wrong. That is not what a blue moon is. Remember, that when our calendar changes months it happens at a different time to different people around the world. But a full Moon happens at an exact time, just like the way Season changes happen at an exact time. So a blue moon based on our calendar does not make sense because based on the time zone you are in, you either have a blue moon or not.
For example, assume the second full moon happens at 11:30pm on August 31 for you (and you think this is a blue moon), and you are standing on the time zone border with someone who is in the time zone ahead of you. For them the full moon happens at 12:30am (after midnight) on September 1st, and it is the first full moon of September and not a blue moon. How can two people who are only a couple feet away from each other be looking at two different moons? Do you see now, how foolish it is to think that a blue moon is the second full moon in a single month?
Ok, so what is a Blue Moon, for real?
As described above, we have a Lunar Calendar with seasons that last about 91 days, and three Moon cycles lasting about 29.5 days each. But, there is a problem. If a "Season" has 91 days, and the average Moon cycle (from Full moon to Full moon) is 29.5 days, then every now and again a "Season" will have 4 full moons, not 3. In fact, this will happen 7 times every 19 years. And this causes a problem.
Remember that we named the 3 full Moons as follows: Early, Middle and Late. And we said that something that happens in the Early Spring Full Moon always happens during the Early Spring Full Moon, and something that happens in the Late Full Moon will always happen during the Late Full Moon. But what happens when there are 4 full Moons that Spring?
What happens in Summer? Everything that happens in the Early Full Moon in Summer (First Full Moon) must still happen during the Early Full Moon. But there have been 4 full Moons since Spring, not 3. How does nature cope? Do things that happen in the Early (First) Full Moon in Summer happen in the now 4th full Moon of Spring instead? Suddenly, the year is one month longer than normal and there is chaos.
Well not really, it turns out nature has an answer. It turns out that nature just "knows". And in this example where Spring has 4 full Moons, the Moons are named: Early, Middle, Blue, Late. So everything that was suppose to happen in the Early Full Moon of Spring still happens then, and the same for the Middle and Late Full Moons of Spring, and when Summer comes next, everything which was suppose to happen during the Early Full Moon of Summer still happens during that full Moon.
A Blue Moon is the 3rd full Moon in a Season which has 4 full Moons.
In this example, the 3rd full Moon in Spring is a Blue Moon. And what happens during a Blue Moon? Quite simply, nothing.