Chapter 134: Cramming education is not advisable (6400 words long chapter)
in the long history of mankind.
The right and wrong between the round earth theory and the flat earth theory has always been a very controversial topic.
When I introduced Zhang Zai before, I mentioned the origin of the round earth theory:
Later generations generally believe that the round earth theory officially appeared in the 6th century BC.
It was the ancient Greek mathematician Pythagoras who first proposed the concept of earth.
Wait until the 3rd century BC.
Eratosthenes, a scientist who lived in Alexandria, used geometric methods to establish the concept of the earth and calculated its diameter.
But what was not explained at the time was that Eratosthenes’ method was actually stupid:
He accidentally learned that at noon on the summer solstice every year, the sun's rays would shine directly on the bottom of a deep well in Sain, Aswan, Egypt.
at the same time.
In Alexandria, which is 5,000 Greek miles north of Saine, the angle between the sun's rays and the vertical line on the ground is 2π/50 radians, which is 7.2°.
Assume that the sun's rays are parallel.
Then according to the formula for calculating the circumference of a circle, a value can be obtained:
That is, the circumference of the earth along the meridian passing through the north and south poles = 5000×2π÷2π/50=250000 Greek miles.
This is just a theoretical derivation, and it can only be said to unify some people's perceptions.
In fact, the theory of a round earth does not just say that the earth is flat with one punch as the data or formulas are solved.
Throughout human history.
There are people in almost every dynasty and every generation who do not believe in the theory of a round earth.
Even in the 21st century, supporters of the flat earth theory are not uncommon.
For example, now, a Flat Earth conference is held across the sea every year - the most recent conference even had more than 600 people attending.
The real number of online participants reached 124,000, and the domestic live broadcast platform became popular in the millions every minute.
YouTube is also flooded with videos claiming to prove that the earth is flat.
Nowadays, local civil science can be regarded as a derogatory term. For example, you can see various design guides like Bagua arrays on the design drawings, or ghost symbols comparable to Xu Yun's calligraphy.
But in front of supporters of the flat earth theory, these civil sciences are really not enough.
Supporters of the flat earth theory believe that the round earth theory is a complete hoax:
The photos of the outer space of the earth are false images taken by the rulers to confuse us, and they are false truths to trap and enslave human beings.
Among them, NBA star Irving is a well-known flat earth supporter.
To be precise.
He is a 'disciple' of one of the "Pac-Man cults":
This sect believes that the earth is flat. If you reach the boundary of the earth, you will instantly appear from the other side of the earth, so you cannot find that the earth is flat...
Kangaroo Country is the opposite country. At one time, there was a kangaroo singer with a shrunken cerebellum who was regarded as a defective product that stopped time.
By the way.
Another star Curry believes that the moon landing was fake and a complete scam.
Quite literally.
In the flat-earth sect, there are countless such bizarre statements.
They have the reputation of not trusting authority (which is actually true), but what they do is all kinds of anti-intellectual and even terrifying things.
Actually.
The flat earth theory is a key fulcrum of the Communist Party's layout, and it is also the core basis of conspiracy theories.
The specific content is too sensitive, so I won’t go into details here.
all in all.
The world is far crazier than we imagine.
This is still the case in later generations, let alone ancient times when the theory of a round earth was not axioms.
Let’s just talk about the three people in the room at this time:
As a professional astronomer who has drawn star maps, Lao Su has a higher acceptance of the round earth theory than others.
He even has some tendency to believe that the earth is round.
But Xiao Li and Xiao Zhao are different.
Although these two young men are very interested in science.
But they have never received any systematic and correct scientific education.
Therefore, when Xu Yun mentioned earlier that the earth was round, some doubts naturally arose in their minds.
If it weren't for the fact that Lao Su listened with great interest.
Xiao Li might have interrupted Xu Yun long ago and asked angrily.
inside the house.
Looking at the excited old Su and the confused Xiao Li, Xu Yun pondered for a moment and said:
"Sir, have you ever been to the beach? - I mean the endless sea."
Old Su nodded when he heard this and recalled:
"Nine years ago, I was ordered to go to Dengzhou to check the navy's food and salary issues. I have seen the ocean.
The water in his mouth was flowing from the sky to the sky, and the old man was shocked to the point of losing his countenance on the spot. ”
Dengzhou.
It was Penglai City in Ludong Province in later generations.
There is the famous Dengzhou Port here, which was also the core place for the Song Dynasty's naval garrison.
Penglai is close to the Bohai Sea and the Yellow Sea, which can indeed be called endless.
Then Xu Yun turned his head and looked at Xiao Li and Xiao Zhao.
Xiao Li thought for a moment and shook his head:
"My father was an official in Huangzhou earlier, and he only crossed the river and never saw the sea."
Xiao Zhao on the side glanced at Xiao Li and said slowly:
"My king is different from Miss Li. Two years ago, I went to Changguo County to purchase medicinal materials for Brother Wang.
Changguo is adjacent to the East China Sea, but it is fortunate to have seen the majesty of the sea. ”
The Chang State of the Song Dynasty is now Zhoushan, Zhejiang Province.
It is connected to the East China Sea and is the estuary of a vast world.
Three people, two have seen the sea.
Although this is not perfect in terms of proportion, it is much higher than Xu Yun expected.
Then Xu Yun pondered for a moment and asked Lao Su and Xiao Zhao:
"Sir, Your Highness Prince Jian, while you are admiring the sea view, have you ever seen a sailboat sailing from a distance?"
Later generations have been quite controversial about the time when sailing ships appeared in ancient China. They are mainly divided into two views: the Spring and Autumn Period and the Han Dynasty.
However, no matter which of the above situations is the case, the timeline must be far earlier than the current Song Dynasty.
So sailing boats are now very common at this time, especially on the coast.
Therefore, Xiao Li and Lao Su just looked at each other, nodded in unison and said:
"I've seen it before."
Xu Yun nodded slightly towards the two of them, took a deep breath, and launched his trump card:
"In this case, I wonder if you two noticed one thing when you saw the sailboat?"
"What happened?"
"Which part of the sailboat first appeared in your field of vision?"
Hearing Xu Yun's words, Lao Su and Xiao Zhao were both stunned.
"Which part?"
Xiao Zhao saw Dahai only two years ago, so his impression was naturally relatively deep, so he took the lead and said:
"If I remember correctly, that day when I climbed up to watch the sea, the first thing I saw seemed to be the white sails, and the second was the hull."
After hearing what Xiao Zhao said, Lao Su also recalled some scenes.
I couldn't help but nodded slightly in agreement.
But as he thought about it, he suddenly realized something.
His eyes widened suddenly and he looked at Xu Yun, with a faint trembling at the corner of his mouth:
"Xiao Wang, are you saying that we saw the sail first because the earth is round, so the sea blocked the hull behind?"
Xu Yun was silent for a moment, nodded solemnly and firmly:
"That's right."
A ship sailing on the sea sees the sail first, and then the hull.
This is the strong evidence that Aristotle once mentioned when proving the shape of the earth.
Of course.
In real life, it is actually quite troublesome if you want to verify this statement with the naked eye alone.
Because according to R+d=(R+h), it can be calculated that a person with a sight height of 1.75 meters can see a horizon distance of 4.65 kilometers.
If you stand on a hill or on a high-rise building, you can see even further.
With this kind of vision range that starts at more than ten kilometers, it is actually difficult for ordinary people to distinguish the sails, masts and hull of the ship.
In this case, the reason why the sail is seen first is largely due to the conspicuousness of the sail and has nothing to do with the sea level.
But it's worth mentioning.
Dengzhou and Changguo are two very special places, different from ordinary coasts:
They were all important places for the navy of the Song Dynasty, and they were also famous sea markets in the Song Dynasty.
Now is the period when the Song Dynasty's sea market was at its most developed, and trade was connected not only with the mainland, but with the surrounding countries.
All ships involved in transoceanic trade are often of extraordinary size.
For example, the famous Song Dynasty ancient ship Huaguang Reef No. 1 was excavated and restored.
The entire ship's hull is 20 meters long, about 6 meters wide, and about 3-4 meters deep. This was only the size of a medium-sized ship in the Song Dynasty.
For example, Dengzhou and Changguo are two maritime cities and important military areas.
If you are lucky, you may even see a sailboat with a 2,000-material level.
As for the so-called two thousand materials.
It is almost 45 meters wide, 11 meters wide and 5 meters deep.
That is, the displacement of a thousand tons is about 40% of the largest treasure ship in Zheng He's fleet.
For a large ship of this size, as long as the weather is good, it is not difficult to distinguish the sails and hull from a very distance.
One of Lao Su and Xiao Zhao was a former prime minister, and the other was Song Zhezong's biological brother. They belonged to the top group of people in the Song Dynasty.
When they went to the sea market, it was as easy as drinking water to see this kind of ship.
Of course.
In the eyes of later generations, seeing the sails first did not necessarily mean that the earth was round.
Because from the perspective of possibility, there is actually the possibility of a donut model.
But at this time, Lao Su obviously didn't think of that much. His mind was almost entirely focused on what Xu Yun said.
As the top astronomer in China or the world at the moment - there is no one like him.
Lao Su's obsession with the stars almost reached a crazy level.
Mentioned previously.
Lao Su once made a telescope that could only magnify five or six times. The observation effect of this telescope was only slightly better than that of the naked eye.
And in 1084 AD.
In order to observe a star in the west direction, Lao Su even took this useless telescope to Tubo!
That's right.
Tibet!
To know.
Tubo in the Song Dynasty was not like later generations. At this time, Uizang and Zhongyuan could be regarded as two different regimes, and there were even some small-scale conflicts between them.
Not only was the journey from Bianjing to Tubo long, but the risks were also staggeringly high.
But in order to pursue the truth, Lao Su did it without hesitation - and the result was 17 stars on Su Song's star chart.
This is Lao Su, a great man of the times who is so persistent that he is not afraid of life and death.
Otherwise, with the same technological level, Lao Su could draw a star map with hundreds of more stars than Europeans. Do you really think it was all about luck?
And as a seeker who has spent a lot of effort on the star chart.
While Lao Su was looking up at the stars, he naturally thought about another thing:
What do the stars in the sky and the earth beneath my feet look like?
It's a pity.
Lao Su's telescope was said to be for long-distance viewing, but in fact it had almost no substantive effect in front of the starry sky.
The real telescope in human history would not be invented until 1608 by Hans Lieber, and Galileo transformed it into an astronomical telescope. Only then did humans truly see the stars above their heads.
Until then.
Even for a genius like Lao Su, the only round planets that could be seen with the naked eye were the moon and the sun.
After all, what is special about him is his brain, not the mutation of his body.
But now with the appearance of the sailboat example cited by Xu Yun, Lao Su suddenly realized
It turns out that the truth was once so close to me!
at the same time.
Perhaps he was inspired by Xu Yun's words.
Another memory fragment came to mind in Lao Su's mind:
More than ten years ago, he once visited Fengcheng in ancient Fengzhou, which was also the capital of later generations of Guangdong people's favorite ingredients.
One night during this period, he was enjoying the cool air in the courtyard and raised his head to look up at the stars as usual.
It didn't take long.
According to his accumulated habits and experience, he discovered the eternal purple star in the north.
But look at it.
A strange feeling suddenly arose in Lao Su's heart:
The Ziwei star he saw in Fengcheng seemed to be a little lower in altitude than the one he saw in Bianjing.
But Lao Su didn’t think much about it at the time:
He just thought that he was a little tired from the long journey and had some deviations in his judgment, so he went back to the house to sleep.
After all, the reduced distance difference is not very obvious, it is very weak, almost nonexistent.
If it weren't for the fact that he often looked up at the stars, he probably wouldn't even have that weird feeling.
But now if according to Xu Yun’s explanation, the entire land is a circle
Then this height problem can be explained:
Because the earth is round, Ziwei Star is in the extreme north.
Therefore, the further north you go, the higher the purple star will be, and the further south you go, the lower the purple star will be
The lower!
That's right.
See here,
Many students must have guessed Ziweixing's identity.
It is what later generations call the North Star, Gou Chen Yi!
But what Lao Su didn't know was.
In his eyes, the so-called eternal North Star is not actually a fixed star, but just a fixed title.
Just like the emperor's throne, different people can sit on it. You will sit on it today, he will sit on it tomorrow, and the Chongzhen trees will laugh.
At present, the polar star Gou Chenyi, which we call very romantic in China, is known internationally as Alpha Ursa Minor.
In fact, it is still about 30 arcminutes away from the North Celestial Pole, about as far as a moon.
As everyone knows.
Due to precession, the direction of the Earth's axis of rotation on the celestial sphere is constantly changing.
So every once in a while, a planet will come to that location.
For example, friends who have lived from 12,000 BC to now should all know,
The North Star at that time was not Gouchenyi, but Vega.
The North Star in 3000 BC was Alpha Draconis, which is the Right Axis.
It is a dim fourth-magnitude star that is very inconspicuous in the sky - for comparison, Gouchenyi is a 2-magnitude star, while Vega is a 0-magnitude star.
By AD 4000, Polaris will become Gamma Cephei.
From a theoretical perspective, there may only be three distance runners on the planet today who have a chance of surviving until then.
By the way.
Antarctica also changes on the celestial sphere.
For example, right now, there are no bright stars near our South Pole.
But by the year 8000 AD, there will be a bright Antarctic star - Iota Carinae, which is also a 2nd magnitude star.
By AD 9000, the Antarctic star will be the even brighter Delta Vela, also known as Cesar III.
But at this time, Lao Su didn't know this secret. He only had another question in his mind.
"Xiao Wang, although the example you gave seems to be able to explain the theory of a round earth, it is still not as good as seeing it with your own eyes."
I saw him staring at Xu Yun, his fists clenched tightly:
"So, do you have a way to let me and others see the stars with their own eyes?"
Xu Yun glanced at him and nodded:
"Yes."
Plop——
Lao Su's heart suddenly twitched heavily, his eyes widened, and he subconsciously blurted out:
"What can I do?"
"Astronomical telescope."
"Astronomical telescope? How to prepare it?"
After hearing what Lao Su said, Xu Yun innocently spread his hands towards him:
"The villain doesn't know."
"You don't know?"
Lao Su's voice suddenly rose a little higher, with strong doubts on his expression:
"How could you not know?"
When Xu Yun heard this, he glanced at Lao Su with a very puzzled look, and innocently spread his hands:
"Master, you don't think that the villain knows everything, do you?"
Lao Su was stunned for a moment.
Seeing that his words seemed to have some effect, Xu Yun continued:
"Sir, I have only seen this kind of tool in the Fengling Yueying Sect's books, but I can barely remember the principle.
But if you want to prepare an astronomical telescope that can see the stars clearly, as well as the microscope mentioned before, there is a problem that must be solved first. ”
"What's the problem?"
An inexplicable light flashed in Xu Yun's eyes and he said:
"Mathematical calculations." (End of chapter)