The Rise of Rurik

Use scraps of wood from the repairing boat as a writing board and charcoal as a pen.

Rurik prepared many wooden boards and a large amount of charcoal, and quickly put into measurement with the participation of other tools.

Because he already knew a lot of key data information, such as the inclination of the earth and the more precise values ​​of pi, these two data are of great significance to the geographic surveying and mapping of the entire earth.

The research on pi has essentially detonated a mathematical revolution.

Because theologians believe in the definition of the world in the ancient school of mathematics, and believe that things created by God must be perfect, pi must also be an accurate value.

Some people are against it, some people are for it, calculating the exact value of pi has become a kind of competition.

But what is the significance of calculating the inclination of the earth and the value of pi?

In today's era, people everywhere don't care about the inclination of the earth, and it doesn't even matter whether the world is a plane or a sphere. Because as long as they are alive, it is already very difficult, and most of the people who can study natural philosophy are theological scholars who eat the food.

It is necessary for those theologians to further demonstrate the greatness of the Lord in this way.

However, pi has at least one important use, which is to calculate the circumference and diameter of a wheel more accurately. This allows craftsmen to create wheels with unique perimeters, which can then be attached to mechanisms dating back to the Greco-Roman period to help lords measure the length of his fiefs, or even the distance between two cities.

But for the Vikings, they didn't have this urgent need. They didn't even have a real city. Even the overcrowded Roseburg was a large "shanty" built by a group of wood and animal skins along the bay area".

During this time, the weather was beautiful, and Rurik was very happy that at noon every day, the sun could normally illuminate the frozen earth here.

The temperature was quite cold, and in order to get an accurate value, Rurik had to go outdoors from time to time to pay attention to the length change of the sun shadow. When the shadow became the longest, he immediately took out a rope ruler to measure it, and put a Data is recorded on wooden boards.

In fact, he only needs one value, and then according to today's date, he can calculate the specific value of the latitude line that the sun shines on the earth today.

The time gradually approached the December month of the Julian calendar, and Rurik knew very well that even if there were already errors in the calendar of this era, the winter solstice was definitely in this month.

This can be reflected from the length of the sun shadow. The sun at noon is only slightly above the horizon, and a standard stika-length wooden pole stands, and its shadow grows amazingly. Even so, Rurik struggled to make statistics.

According to the simple Pythagorean theorem, he used charcoal as a pen on a wooden board and performed some trigonometric functions to obtain an angle value, a very sharp acute angle.

The most important thing Rurik needed to know was the direct angle of the sun on the day of the measurement.

Theoretically, because the sun on the autumnal equinox absolutely shines directly on the equator, and on the winter solstice, the sun absolutely shines directly on the Tropic of Cancer, which is 23°26′ south latitude, which is a very precise value.

In this era, December 22 of the Julian calendar is the winter solstice, and it is not credible.

However, Rurik has measured multiple values ​​one after another!

He tentatively set the winter solstice as December 22, and the next step is to bring in the formula.

Since for a quarter of a year, the direct solar angle changes only by 23°26' in dimensionality, Rurik calculated a very accurate value for the daily change of the direct solar angle. In this way, he calculated that on December 1, the direct angle of the shot had exceeded 17°.

For example, on December 1st, a cold, dry and sunny day, he measured the angle of the sun's shadow on the pole to calculate the direct angle of the sun today, and finally subtracted two data from 90° to naturally obtain the local latitude data.

In fact, Rurik has obtained five data in a row,

The error between each other is not big.　　

All the data show that Roseburg's position is around 63° north latitude, with an error of about 1°.

It seems that Rurik's experiment at the junior high school level has been successfully completed. After all, he has not used more of his knowledge.

So he was very satisfied with the math results he got with his dark hands after so many days of work? Do not! He is not satisfied.

Because it is only 63° north latitude, even with a maximum error of 64°, Roseburg is not enough to fall into the polar night of even one day.

Contrary to what he felt, there was a polar night in Roseburg.

Therefore, your own measurement needs to continue.

Affected by the existence of the polar night, on the day of the winter solstice, the east will only be slightly red, and the sun seems to be coming out, but it does not appear. If there were haze in those days, the situation for many days would be no different from the polar night.

Obviously, in Rossburg, the local latitude cannot be measured by the solar shadow. If you want to obtain an accurate result only by measuring, you obviously have to wait until the summer solstice. That is, the so-called day when the shadow of the day becomes the shortest, and the summer solstice is this day. To get the data of the summer solstice, you must also measure for a long time and record the data.

This matter will be a very huge project, do you want to become the first astronomer of the Ross tribe?

It is undeniable that the measurement of the shadow of the sun to determine the time is also very important to the Rus tribe. After all, they must go to their servant Novgorod at the right time to collect an offering, especially in autumn with a batch of rye. , Wheat has returned in victory.

In ancient times, for any huge country, the source of the stability of the country was enough food.

A huge country means a huge population. Only by growing crops and eating grains can a country maintain a huge population and remain stable.

The planting and harvesting of grain is closely related to the changing seasons. A big country must set its own calendar.

The only thing that can be used as an effective reference for compiling the calendar is probably only the moon and the sun, and finally the lunar and solar calendars are compiled. There are also Mayans who came up with non-mainstream calendars. In addition to the yin and yang calendars, they also have the Venus calendar.

The calendar is surveyed, mapped and compiled by the state, and the subsequent revision rights are also in the state, because the common people have almost no knowledge of astronomy.

When Rome entered the empire, it was especially in need of Egyptian food production. To a large extent, the ever-increasing demand for food also shaped the direction of the empire's expansion. Rome was happy to land and take possession of Britain, because the fields here were developed very early, and he was really fertile. For the safety of the agricultural area, they simply built a Hadrian's Stone Wall.

And those forest areas in Central and Eastern Europe have long been the areas of Slavic tribes, because these areas really lack agricultural value, so that the Slavs can wander for a long time as forest hunters.

Western Rome fell, and Eastern Rome once inherited the territory of Western Rome. They lasted for a short time and were eventually taken away by the Franks.

The Frankish kingdom was established on the ruins of Western Rome, and a series of things have been completely different from the previous Roman period.

But the settled barbarians needed to farm the land to support themselves, and they relied heavily on the calendar developed by the Romans, but few people thought that the calendar would gradually become inaccurate over time.

A year of the Julian calendar is a little shorter than the revolution period of the earth. After 800 years of accumulation, the error of the calendar has actually reached six days!

Therefore, the winter solstice marked by the Julian calendar at this time is completely inconsistent with the reality.

Of course Rurik knew this, but he just didn't understand what the error in the calendar was like.

Do you have to measure the exact summer solstice yourself?

You don't have to!

The wise Rurik suddenly thought of something that made his hair tremble, because over the years, Veria has always been able to accurately predict which day the sun will not rise, and that day is the tribal tradition of Hanukkah. Tribes will revel in revelry, drink and sing, and watch the first rays of the New Year's sun shine on the frozen sea of ​​the bay.

Veria, she knows the winter solstice!

Does she know the "Heliometry"? Or do you know about other measurements? !

She also knows the theory that the world is a sphere, maybe she already knows a lot about geography, but hasn't revealed it to others?

Could it be that she is still a classical astronomer in her seventies? !

The more Rurik thought about it, the more frightened his heart became. He thought about his measurement work in the past few days. Veria was a quiet observer. She had been silently watching her series of work.

Maybe, when he was busy, Veria understood everything many years ago?