We inherited 360 degrees from the Babylonians, but many ancient societies were highly interested in astronomy and in some (megalithic Britain?) had 366 degrees in a circle.  

There are 366 sunrises per orbit of the sun, therefore one 366th part of the horizon = 1 megalithic degree. First place two posts at 1 degree apart on the horizon (They do not explain how this is done). Then swing a pendulum so that it beats 366 times in the time it takes a star to travel between the posts (This is a very specific request, which would require a metronome). The length of line required for the pendulum will be 16.32 inches in length = half a megalithic yard. (1)

This is logical, since the earth turns on its axis 366 times a year. Their measurements seem to have been interrelated and not arbitrary as a metrically divided circle would be. The Babylonians probably reduced this to 360 as it divides so much more easily by many factors.

tumblr_nsanldrCAv1qg20oho1_540Furthermore, 360 has many more divisors than 10, 100, 1000 etc. Therefore a circle can be divided more easily into many diferent equal parts – 2,3,4,5,6,8,9,10…

According to hypothesis of Alan Butler and Christopher Knight, megalithic civilisation of Britain and Brittany, France used  366-degree geometry (also called megalithic geometry). This geometry, whose origin is claimed to go back to c. 3,000 BC, would have used a 366-degree circle rather than a 360-degree circle as we do today.LucasCirclesTangentCircles_1000366 Degrees


Alan Butler also asserts that 366-degree geometry has been materialised on the Earth by what he terms Salt Lines – 366 meridians and 183 parallels crisscrossing the globe at regular intervals (the equivalents of modern-day 360 meridians and 180 parallels).


According to Sylvain Tristan, most of the world’s capital cities or sanctuaries of late prehistory and antiquity are located on the course of Salt Lines: it includes Stonehenge, Avebury, the Ring of Brodgar and Skara Brae (both of which are located on the 60th Megalithic parallel), Babylon, Assur, Niniveh, Thebes, Abu Simbel, Harappa, Mycenae, Athenes, Hattusa, Alesia, Teotihuacan (20th Megalithic parallel), Chichén Itzá, Tiwanaku and Caral. According to the author, such a situation challenges probability laws and can hardly been explained away by chance only, and thus is the result of some common knowledge held by the Megalithic civilisation that might have spread to different parts of the globe.

Butler and Knight claim that the Megalithic Yard is a fundamental number for the Sun, the Moon and the Earth. The Megalithic arc second as measured on the Earth equator is very close to 366 Megalithic Yards, while the lunar Megalithic arc second as measured on the Moon equator is very close to 100 Megalithic yards, and the solar Megalithic arc second as measured on the Sun equator is very close to 40,000 Megalithic Yards.

French author Sylvain Tristan suggests that the numbers 366, 40 and 10 are not only fundamental to the Earth, the Moon and the Sun, but also to the human body and water.  The cosmological relationship of the Earth and the Moon shows the harmonious numerical design.

Special Numbers: 366, 40, 10 and 2732

Moon diameter = 0.2732 Earth (polar) diameter
Moon 0rbital period: 27.32 days
Moon rotation period: 27.32 days

366 degree geometry leads to another interesting number: 1/366 =  0.002732

In the water-based Celsius temperature measurement system, which is directly linked to base-10 numeration, the average human body temperature is 36.6 degrees. On a scale where the absolute zero is defined as being minus 1,000 degrees, water boils at the temperature of 366 degrees, which points at something intrinsically fundamental in these numbers.

According to Butler, 366-degree geometry is linked to the Phaistos Disc, which has been interpreted by some as a Minoan calendar based on a 366-day year, the Phaistos Disc having 30 divisions on one side and 31 on the other. This calendar would have been working on 40-year cycles, because a 366-day calendar needs one intercalary month in 40 years.

The Phaistos Disc (side A)
The Phaistos Disc (side A)

200px-Δίσκος_της_Φαιστού_πλευρά_B_6381A leap year has 366 days, as opposed to a common year, which has 365. Nearly every 4 years is a Leap Year, and we add a Leap Day, an extra – or intercalary – day on February 29.

Leap Years are needed to keep our modern dayGregorian Calendar in alignment with the Earth’s revolutions around the sun. It takes the Earth approximately 365.242199 days – or 365 days, 5 hours, 48 minutes, and 46 seconds – to circle once around the Sun. This is called a tropical year.

However, the Gregorian calendar has only 365 days in a year, so if we didn’t add a day on February 29 nearly every 4 years, we would lose almost six hours off our calendar every year. After only 100 years, our calendar would be off by approximately 24 days!

In the Gregorian calendar 3 criteria must be taken into account to identify leap years:

  • The year is evenly divisible by 4;
  • If the year can be evenly divided by 100, it is NOT a leap year, unless;
  • The year is also evenly divisible by 400. Then it is a leap year.

This means that 2000 and 2400 are leap years, while 18001900210022002300 and 2500 are NOT leap years.

The year 2000 was somewhat special as it was the first instance when the third criterion was used in most parts of the world since the transition from the Julian to the Gregorian Calendar.

1.618 is a number all serious designers should know. It’s known as the golden ratio found throughout nature, art and architecture.

Seashells, Mona Lisa


Seashells, the Mona Lisa and the Parthenon all show the golden ratio. Our faces and bodies are also proportional to the golden ratio. It’s so omnipresent that it’s even found in sounds and intervals of time. If there ever was a mathematical way to explain and express natural beauty, the golden ratio is it.

Ever wondered why things look so good? The Golden Ratio! is applied