**In the surviving books of the Maya, the mysterious principle of chronology was encrypted, based on a cycle of 819 days.**

Most likely, everything that we do not know yet is something that we simply do not notice due to inattention. For example, once on a tour of the museum, the famous US physicist Richard Feynman was one of the first to embrace the incomprehensible depths of the world of quantum particles.

Going to museums was in no way part of his scientific interests, but he did his best to “cultivate himself” and in general was a sincerely curious person. So, the scientist was interested in all these numerous points and lines.

This is a fragment of one of the 78 pages of the famous ancient book of the Maya Indians. It was written in the 13th century on paper made from ficus bark. Since it became famous after the Dresden librarian bought it in the 18th century, it is now called the Dresden Codex.

As Feynman later told his friends, he bought a printed copy of the code, came to the hotel, began to meticulously count all these points – and very quickly discovered that there was a logic to it. It all comes down to certain numbers and then one suspicion crept into his mind: he compared these numbers with some parameters of the movement of celestial bodies – and realized that these Indians were excellent astronomers.

Of course, many scientists, except for Feynman, have deciphered and continue to decipher the Dresden Codex as well as other Mayan documents, and all kinds of inscriptions on their temples. A careful comparison of some details led the researchers to the conclusion that this civilization led some other unknown calendar in addition to those that are already known.

It is known that they had two main calendars. One – “mundane”, 365-day: 18 months of 20 days, plus five more days at the end of the year for good measure. The second is special, sacred and very ingenious: there are 260 days, numbered from 1st to 13th, and the symbolic names of these days are repeated with a period of not 13 days but 20.

It turned out that the Maya had a third way to count days, and it is so complex that comprehending it in the 21st century is a real challenge to science. In fact, all that is given in this problem is that the main cycle in the mysterious calendar lasts 819 days but why exactly 819, one can only guess. At the same time, 819 days is one of four equal parts of a large cycle with a total of 3276 days. What almost immediately came to the mind of scientists is that 3276 days is nine times 364 days. You could say almost nine years. But again – what happens or happened in the world of the Mayan Indians every nine years?

On this account there was a space version: in fact, nothing, perhaps remarkable, happened every 3276 days, but it was just the most convenient number. Convenient for what? It was easy to divide it into cycles of travel of several different celestial bodies at once through the night sky. We are talking about the so-called synodic period – the period after which the celestial body is exactly in the same position in the sky. This is not the period of revolution, say, of a planet around the Sun, but the period of its sometimes intricate movement across the sky. The period of “apparent” movement.

Actually, the planet goes around in a circle (well, on an ellipse), and we see that it goes, let’s say in one direction, then in the other (we remember the legendary retrograde Mercury). It is clear that a planet in its orbit always moves in the same direction, but it regularly seems to us that it is flying backwards, because we are also moving together with the Earth, and we are not moving synchronously with Mercury: Earth has its own speed, Mercury has its own.

It is these observations of the visible motion of the planets which probably formed the basis of the calendar. If, for example, we take the synodic period of the same Mercury, then it amounts to no less than 116 days. Multiply by seven and we get 812. Very close.

Venus: 583 days. It’s more complicated here, but it can also be synchronized: the seven synodic periods of the Morning Star are almost five times 819 days.

Jupiter: 398 days. 39 times 398 is almost 19 times 819. With Saturn, it’s generally perfectly clear: it has this apparent cycle of movement of 378 days, and 13 times 378 is exactly six times 819.

In principle, a person who used this calendar, could take any planet as a basis and count the days in accordance with its movement across the sky. If you bring it under the moon, its 3276 days, equal to 30 times 27.3 days. Thirty lunar months.