Subsequently, Xu Yun pondered for a moment and asked Old Su and Xiaozhao:

"Gentlemen, Prince Jian, while you were admiring the sea view, did either of you happen to see a sailing ship approaching from afar?"

The appearance of sailing ships in ancient Huaxia has always been a topic of debate among later generations, mainly divided into two perspectives: the Spring and Autumn theory and the Han Dynasties theory.

However, regardless of which of these scenarios, the timeline is far earlier than the current Song Dynasty.

Therefore, at this time, sailing ships are quite common, especially by the seaside.

Hence Xiaoli and Old Su just glanced at each other and nodded in unison, saying:

"Of course, we have seen them."

Xu Yun nodded slightly to the two of them, took a deep breath, and presented his trump card:

"In that case, when you saw those ships, did you notice one particular thing?"

"What thing?"

"Which part of the ship first appeared in your view?"

Upon hearing Xu Yun's words, Old Su and Xiaozhao were momentarily stunned.

"Which part?"

Xiaozhao, having seen the sea only two years ago, had relatively fresh impressions and spoke first:

"If I'm not mistaken... on that day, when I climbed high to observe the sea, I first saw the white sails, and then the hull..."

Hearing Xiaozhao say this, Old Su recalled some images as well.

He couldn't help but nod in agreement.

However, as he continued to think, he suddenly realized something.

He abruptly widened his eyes, looked at Xu Yun, and his mouth began to tremble slightly:

"Xiaowang, are you saying we first saw the sails because the Earth is round, and the sea blocked the hull behind?"

Xu Yun paused for a moment and then nodded solemnly and firmly:

"That's correct."

From a ship at sea, the sails are seen first, then the hull.

This was a crucial piece of evidence Aristotle once cited to demonstrate the shape of the Earth.

Of course.

In real life, relying solely on the naked eye to verify this claim is actually quite troublesome.

Because, according to the calculation R²+d²= (R+h)², a person with a sightline height of 1.75 meters can see the horizon up to 4.65 kilometers away.

If you stand on a mountain or a tall building, the range you see expands even further.

In this visual range that spans several kilometers, most people actually find it difficult to distinguish between sails, masts, and hulls.

In such cases, the so-called first sighting of the sails is largely due to the conspicuousness of the sails, having little to do with the sea level.

But it's worth mentioning.

The places like Deng Prefecture and Changguo are quite special, different from the usual coasts:

They are significant naval bases of the Song Dynasty, and also renowned sites for maritime trade.

Currently, it is the most prosperous period for maritime markets in the Song Dynasty, with trade connecting not the inland, but various surrounding countries.

Moreover, ships engaged in transoceanic trade are often atypically large.

For instance, the well-known ancient Song ship, Huaguang Reef No.1, which was excavated and restored.

The entire remains of the ship are 20 meters long, about 6 meters wide, with an average depth of 3 to 4 meters, which in the Song Dynasty is merely a medium-sized ship.

In Deng Prefecture and Changguo, both being maritime and military hubs.

If you are lucky, you might even see two-thousand-ton-class hybrid sailing and oared vessels.

As for the so-called two-thousand tons...

It is approximately 45 meters long, 11 meters wide, and 5 meters deep.

This equates to a thousand-ton displacement, about 40% of the largest treasure ships in Zheng He's Fleet.

This scale of large ships, as long as the weather permits, makes it still possible to distinguish the sails and hull from a great distance.

Old Su and Xiaozhao, one a former prime minister, the other the younger brother of Emperor Zhezong of Song, belong to the top echelon of the Great Song.

When they go to maritime markets, seeing such ships is as easy as drinking water.

Of course.

From a later perspective, seeing the sails first doesn't necessarily mean the Earth is round.

Because, from a hypothetical angle, there is also a possibility of a donut model.

But at this time, Old Su clearly had not thought so far, almost entirely focused on what Xu Yun said.

As the foremost astronomer not just in Huaxia, but globally at the time, without any peers.

Old Su's obsession with the stars reached a near-madness level.

It was mentioned before.

Old Su once made a telescope that could only magnify five or six times, and its observational effect was just slightly better than pure naked eye observation.

And in the year 1084.

Old Su even took this useless telescope to Tubo to observe a star in the west!

Indeed.

Tubo!

It must be noted.

Tubo under the Song Dynasty was not like the later times; at this time, Weizang and the Central Plains could be considered two different regimes, with some minor conflicts between them.

The journey from Bianjing to Tubo was not only long but also incredibly risky.

Yet, in pursuit of truth, Old Su did it unhesitatingly—the result being the 17 stars on the Su Song Star Map.

This is Old Su, a pioneering figure of the era, unafraid of life and death.

Otherwise, under the same technological level, how could Old Su draw a star map with hundreds of stars, more than Europeans, really think it's all luck?

And as a seeker who spent much effort on star charts.

While looking up at the stars, Old Su naturally contemplated another question:

What exactly do those celestial stars and the land beneath him look like?

Unfortunately.

Old Su's telescope, though called 'telescopic,' was practically useless when faced with the starry sky.

The true breakthrough in telescopes wouldn't occur until 1608, when they were invented by Hans Lippershey, and Galileo later turned them into an astronomical telescope, allowing humanity to truly see the stars overhead.

If you find any errors ( broken links, non-standard content, etc.. ), Please let us know < report chapter > so we can fix it as soon as possible.