"But ordinary stars are also quite interesting, we found that the stars in the sky may be bigger than we thought, and the reason why they look small is because they are too far away." Shi Shen said as he wrote that in the past, only more than 2,000 stars could be seen in the sky, but since the telescope, the number of stars has suddenly increased several times.

Although this telescope is 108,000 miles behind the astronomical telescopes of later generations, it is already an artifact-level thing in this era.

"The distance between the sun and the center of the earth is 80,000 li, and the distance to the royal city is 100,000 li. However, after we recalculated, the statement that the length of the sun's shadow is one inch and the difference between north and south is one thousand miles is wrong. The difference in the length of the shadow in different places and different time periods also has an impact. ”

"There's a big difference between summer and winter. Moreover...... the method in the "Zhou Ji Sutra" is based on the fact that the ground is flat, and if the ground is a ball, then the method used in the "Zhou Ji Sutra" is wrong. We doubt ...... The distance from the sun to the ground is not fixed, but changes back and forth in an annual cycle, which explains why there are springs, summers, autumns, and winters. Gander said.

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In order to study these things, he and Shi Shen even listened to Zhao Kuo's physics and mathematics knowledge every day, and they were more serious than when they were young.

In the past, the two always said that they had lived enough, but now they talk about not enough time every day.

"You mean the sun is moving back and forth? Or move up and down? Yin Gao's train of thought couldn't keep up with Gander.

"We doubt...... The sun is not moving, the earth revolves around the sun. For according to our calculations, the diameter of the sun is ten to fifteen times that of the earth, and forty to fifty times that of the moon (error). Gander whispered, he only dared to say it in front of Yin Gao, if he said it in front of others, he would be tied up and burned to death.

"How do you explain that the sun rises in the east and sets in the west?" Yin Gao asked calmly, there was no wave in his heart, and he even wanted to eat a date.

He would not have been surprised by the words that came out of the mouths of these two old men.

"If the earth is a ball and itself rotates around an axis, that would explain that." Gander took a date out of the basket, held it up in front of him, and let go of his fingers, causing it to fall to the ground.

However, this statement does not explain why the dates fell straight to the ground, not to the west. It's like there's no way to explain why the dates hit the ground after they're thrown out, instead of flying away. So we're just speculating, and there's no way to prove it yet. ”

If it can be proved that he has written a book a long time ago and announced his new discovery to the world, as long as he can dismiss everyone, he will be a great master in the future. But now I can only hold back, for fear of being regarded as a heretic by others.

"If the earth is spherical and revolves around the sun, and the distance is not fixed, then there is no way to calculate the distance from the ground to the sun." Yin Gao said.

"There's a way." Gander took out a piece of paper from the side, and drew a diagram on it, as well as three small balls, representing the sun, the earth, and Venus, and below was a large number of calculations, densely packed, and there were many more on the table.

"We have calculated that the distance from the ground to the Sun is five times that from the ground to Taibai (Venus), and when we reach the transit of Taibai (Venus), we can observe the transit of Taibai at the same time at two locations thousands of miles apart. At this time, the observed Taibai positions of the two points are different, and then the distance between the two points is inferred according to the different durations of the observed Taibai transit in the two places. ”

"Using the distance between the two places on the earth, calculate the distance of the black dot formed by Taibai on the sun, and calculate the diameter of the sun according to the multiple of the black dot and the sun, and then calculate the distance from the sun to the ground according to the angle."

"As for the time problem, you can use the latest clock made by the Mo family to solve it."

More than 100 years ago, Mozi invented a rotating roulette wheel, which was the prototype of the Rui wheel pod invented by Zhang Heng later, but later Mozi felt that it was useless and threw it away, and Zhang Heng was only used as a calendar, but this thing can be used as a clock with a little modification, and the accuracy is already first-class in the current era.

"Too white and sunny!" Yin Gao himself was also a first-class astronomer and mathematician at that time, and after a little thought, he understood the principle inside, and it is difficult to say whether it can be realized in practice, but there is no problem in theory, and the question now is - when will Taibai Ling Ri come.

"The last time there is a record of the transit of Taibai was the tenth year of King Zhou (King Zhou Xun) (305 B.C., according to the time calculation, there will indeed be a transit of Venus in this year). The comet crossed the sky, and it didn't take long for the phenomenon of Taibai Transit to appear, and Tang Yu of Chu State recorded it, it has been nearly fifty years ago, who knows when the next Taibai Transit will be? Yin Gao shook his head.

Although they discovered the phenomenon of Taibai Transit, they did not summarize the pattern.

"We may not live to that time, but you're still young and there's hope. The descendants of our two families have no talent in this area, so we can only rely on you. When the results are out, just go to the graves of the two of us and tell us. Gander said with a sigh.

Even those who have the deepest research on astronomy in contemporary times don't know how many years the Taibai Transit will occur, and even if this method will work, they don't know the bottom in their hearts.

In the Shang and Zhou dynasties, there were special officials to record this kind of celestial phenomenon, but with the wars and wars, these ancient books have long been lost.

If it had been before, Gander and Shi Shen would definitely leave this problem to future generations, in this era, what the ancestors told before they died, as long as the descendants did not die, they would have to complete it desperately.

However, after meeting Yin Gao, he decided to leave the problem to Yin Gao.

After all, compared to Yin Gao, his descendants are waste, even if they are really desperate, I am afraid that there will not be much progress, and Yin Gao is the only junior who may reach the height of him and Shi Shen.

What he didn't know was that the next Venus transit would have to wait until seventy-five years later, if nothing else, let alone him, Yin Gao's grave grass was a few feet high.

"Can't you use the transit of the star 'Mercury' to calculate it?" Yin Gao said with a frown.

"Chenxing is too far away from the earth, and the parallax we see is too small, and I am afraid that it is impossible to calculate accurately at our level. Even if you use the Taibai Transit Sun, there will be a lot of error. Shi Shen shook his head.

He had long thought of using the Transit of the Star to calculate, but on the one hand, it had been two years since the last Transit of the Star (it should be this time), and he didn't know when the next time would be.

On the other hand, as Shi Shen said, the distance is too far, the error is too large, and there is no way to calculate it at the current level.

"If I could meet it, I would do my best." Yin Gao said solemnly.