15 replies to this topic

[blackriverdragon]

So, I've read a bit about how people from India discovered the world is round, how the Classical Greeks did it, and, to a lesser extent, how Medieval Europe already knew that the world is round. But I haven't found much on when the Chinese found out about how the Earth is spherical. When did this happen? Who is credited with this discovery? I'm pretty sure that the sailors and navies must have noticed something funny with the horizon and the stars and the latitudes, but when? How widely did this knowledge circulate? Did generations of the imperial family remain ignorant of this fact long after it was discovered?

I'm aware that ancient Chinese cosmology said that the Earth is square and the sky is circular. How was knowledge of a spherical Earth reconciled with this belief? Or did not enough people know about Earth's roundness that people continued to believe that the Earth is a square up until . . . I don't know when spherical Earth became widely known knowledge.

[William O'Chee]

I'm aware that ancient Chinese cosmology said that the Earth is square and the sky is circular. How was knowledge of a spherical Earth reconciled with this belief? Or did not enough people know about Earth's roundness that people continued to believe that the Earth is a square up until . . . I don't know when spherical Earth became widely known knowledge.

Well, I am not actually sure that the Chinese believed the Earth was square. A square symbol was used to symbolise the Earth not because it was actualy believed to be square, but because it symbolised the ninefold division of fields in a feof.

[DaMo]

The square is also used to symbolize earth in ancient Indian element representations.

As with most theories before they could be actually verified empirically, the round earth theory was probably not really widespread until then. But in ancient China, it is probably at least as old as the Eastern Han, if the statement by polymath Zhang Heng can be taken at face value:

The sky is like a hen's egg and is as round as a crossbow pellet. The Earth is like the yolk of the egg, lying alone at the center. The sky is large and the Earth is small.

http://hua.umf.maine...gHeng6539w.html

[LYY]

So, I've read a bit about how people from India discovered the world is round, how the Classical Greeks did it, and, to a lesser extent, how Medieval Europe already knew that the world is round. But I haven't found much on when the Chinese found out about how the Earth is spherical. When did this happen? Who is credited with this discovery? I'm pretty sure that the sailors and navies must have noticed something funny with the horizon and the stars and the latitudes, but when? How widely did this knowledge circulate? Did generations of the imperial family remain ignorant of this fact long after it was discovered?

I'm aware that ancient Chinese cosmology said that the Earth is square and the sky is circular. How was knowledge of a spherical Earth reconciled with this belief? Or did not enough people know about Earth's roundness that people continued to believe that the Earth is a square up until . . . I don't know when spherical Earth became widely known knowledge.

(1) IMO, the Chinese never discover the earth is spherical.
(2) The Earth is said to manifest the quality of squareness in order to answer to the call of Heaven - the quality of roundness.
(3) The harmony of MAN with his world is to walk a path that rounds the steps of Heaven in squaring the Earth.
(4) When the ancient people in the Middle Kingdom squares the Earth, it is like how the Methodists squaring the Bible teaching.
(5) When the ancient people in the Middle Kingdom rounds the steps of Heaven, it is the basic idea why the Jews take a break on Sunday.

Instead of saying the idea of spherical earth fits well into "Heaven is Round, Earth is square", it would be more appropriate to say that the Trinity Model of Heaven-Earth-Man is isomorphically universal - a deduction of universal phenomena that tend to recurse from bigger worlds to smaller worlds ...

Edited by LYY, 09 June 2009 - 08:29 PM.

[William O'Chee]

The square is also used to symbolize earth in ancient Indian element representations.

As with most theories before they could be actually verified empirically, the round earth theory was probably not really widespread until then. But in ancient China, it is probably at least as old as the Eastern Han, if the statement by polymath Zhang Heng can be taken at face value:



http://hua.umf.maine...gHeng6539w.html

Great quote!

[General_Zhaoyun]

Well, I am not actually sure that the Chinese believed the Earth was square. A square symbol was used to symbolise the Earth not because it was actualy believed to be square, but because it symbolised the ninefold division of fields in a feof.

For ancient Chinese cosmology of "round heaven and square earth", refer to this thread: http://www.chinahist...showtopic=28401

I'm aware that ancient Chinese cosmology said that the Earth is square and the sky is circular. How was knowledge of a spherical Earth reconciled with this belief? Or did not enough people know about Earth's roundness that people continued to believe that the Earth is a square up until . . . I don't know when spherical Earth became widely known knowledge.

I don't think the thought about "Earth being round" came from China. The ancient Chinese had always believed that the earth was square, which originated from Yin-yang cosmology

I think the thought of "Earth being round" originated from the West. It was first proposed by Greek Philosopher and Mathematician Pythagoras and later Aristotle was the first person to come up with scientific proof for "Earth being round" based on the eclipse of the Moon. Anyway, that was 300 BC.

China first got to know that the "Earth was round" during Ming dynasty through Italian Jesuit Matteo Ricci. It was Matteo Ricci who first introduced to China about the Portuguese Explorer Ferdinand Magellan's circumnavigation of the Earth in 1519, which proved that the Earth was round. China got to know that the "Earth was rotating around the Sun", after the Polish astronomer Copernicus Nicholas proved his theory scientifically about Sun being at the center of the universe.

Edited by General_Zhaoyun, 22 June 2009 - 07:03 AM.

[Tibet Libre]

But I haven't found much on when the Chinese found out about how the Earth is spherical.

In the 16th and 17th century, through the contacts with the Jesuits. Chinese scholars initially had great problems accepting it as a fact, since a spherical earth means that the notion of China being the Middle Kingdom, at the center of the world, is absurd.

It should be pointed out that all knowledge of the spherical earth ultimately stems from only a single source, the Greek discovery. In other words, later Roman, medieval, Muslim and Indian traditions borrowed from their initial findings.

[The Stoic]

Most people have already hit the highlights of this question. I just wanted to add something that might help the questioner.

For the life of me, i can't remember which monograph, but I believe one cultural/social historian and one historian of science both pointed out that a major stumbling block to the conception of a round earth and other astronomical phenomena was due to a severe lack of geometric knowledge on the part of the Chinese. Euclidean geometry helped both the Roman and Islamic inheritors of Greek science advance cartographic and astronomical studies.

There was also the problem of Chinese astronomy being "married" to certain cosmological postulates established during the era of the Han synthesis and carried forth until past the Song.

[sy8kin8h]

It should be pointed out that all knowledge of the spherical earth ultimately stems from only a single source, the Greek discovery.

Not really,the Ancient Egyptians and many ancient civillization,IIRC,also knew that the Earth is spherical,independently.It was the Greeks that calculated the Earth's circumference.

[Tibet Libre]

Not really,the Ancient Egyptians and many ancient civillization,IIRC,also knew that the Earth is spherical,independently.It was the Greeks that calculated the Earth's circumference.

No, the ancient civilizations all thought the earth to be flat, as far as their beliefs can be extracted from their surviving records. All knowledge that the earth is spherical derives from the Greeks who were the first to observe, describe and explain the sphericity of the earth. Aristotle himself gave several reasons like the semi-circular shape of the earth on the moon's surface during a lunar eclipse.

This knowledge was preserved thoughout the Middle Ages, with both Aristotle, the philospohus, and Thomas Aquinas, who followed Aristotle, the theologician, being the main authorities to propagate a round earth. Interestingly, the Globus cruciger of the Holy Roman emperors (of German ethnicity) had the round shape of the earth with a Christian cross on top, symbolising Christian dominion of the world.

The Indians got the concept through their adoption of Greek astronomy in the wake of Alexander's conquest and Hellenistic influence in Middle Asia and the Ganges plains (the Gandhara period in art). The Romans in the west adopted it directly from Greek works, as later the Muslim Arabs did it though translation of the Greek astronomical corpus. The medieval West got it from the Romans and transmitted it through the Jesuit mission to China which was the last major civilization on the earth to get acquainted with the concept - in the early 17th century.

It has been one and the same ultimate source for all, the observations of ancient Greek astronomers.

[William O'Chee]

The real test of whether a people know the world to be round must - in the absence of some calculation of circumference - lie in their navigational theory.

It is fairly easy to navigate one's way around the world by following a line of latitude, such as the equator, or the 40th parallel or such. This can be done simply by finding a star wit the same declination and keeping that overhead as one sails or travels.

The problem is that the further one gets from the equator, the smaller the distance between each line of longitude. For example, travelling two hundred miles east-west on the equator means going through a smaller angle of langitude than doing so in the Arctic circle. Recognising this leads to an acceptance that the world must be spherical. If one does not understand this, one ends up with a square or rectangular, and flat, world.

I know Chinese navigational maps were constructed differently from those in the West, but at some point they had to cover this point. At what point did the Chinese understand the problem of getting the correct longitude at different distances from the equator?

[Tibet Libre]

The real test of whether a people know the world to be round must - in the absence of some calculation of circumference - lie in their navigational theory.

True, it took Magellan's circumnavigation to provide the practical proof for the theory of the sphericity of the earth, but Aristotle anticipated the curved nature of the earth's surface very much by pointing out that the masts of a leaving ship are the last to disappear from the horizon. This was sound empirical evidence. Columbus would have never dared sailing across the open ocean if the sphericity of the earth had not been common knowledge by his time.

At what point did the Chinese understand the problem of getting the correct longitude at different distances from the equator?

I don't know, but the real problem in the history of navigation was getting the right latitude . So much that the 18th century British admiralty had offered a award for the solution of that problem.

Edited by Tibet Libre, 08 February 2010 - 11:35 AM.

[Kanzi]

I don't know, but the real problem in the history of navigation was getting the right latitude . So much that the 18th century British admiralty had offered a award for the solution of that problem.

Sorry, but it WAS the longitude that caused problem. Latitude is easily measured if you know the date, and measure the elevation of the sun at noon. To calculate the longitude, you need to know the time of day (say noon, when the sun is highest), and then compare with the time at the place from where you left. Thus, you need a good clock! The more precise the clock, the better the longitude calculation. That problem spurred the development of more accurate, as well as portable, clocks in Europe, when they started navigating around the world. Other techniques were proposed. For example, Galileo thought of using the Jovean satellites to measure longitude (not exactly sure how), but that was impractical in a boat, since you needed very accurate telescope observations. Before that, European clocks, though neat mechanical machines, were no more nor less accurate than other time-keeping technologies, like water clocks. In fact they were pretty unreliable.

The Chinese, and other nations as well, navigated along well known routes from east Asia to the Indian ocean. There was much less need for accurate longitude measurement.

As for the main topic (spherical earth), it seems odd that the Chinese would not have known about it at one time or another. Certainly Arab astronomers were aware of it, since they shared the same hellenistic tradition (Ptolemy, Aristotle), and there were many contacts between Chinese and Arab astronomers during the Yuan period and after (Arabs were the "foreign experts" in astronomy before they were supplanted by the Jesuits).

[William O'Chee]

Sorry, but it WAS the longitude that caused problem. Latitude is easily measured if you know the date, and measure the elevation of the sun at noon. To calculate the longitude, you need to know the time of day (say noon, when the sun is highest), and then compare with the time at the place from where you left. Thus, you need a good clock! The more precise the clock, the better the longitude calculation. That problem spurred the development of more accurate, as well as portable, clocks in Europe, when they started navigating around the world. Other techniques were proposed. For example, Galileo thought of using the Jovean satellites to measure longitude (not exactly sure how), but that was impractical in a boat, since you needed very accurate telescope observations. Before that, European clocks, though neat mechanical machines, were no more nor less accurate than other time-keeping technologies, like water clocks. In fact they were pretty unreliable.

The Chinese, and other nations as well, navigated along well known routes from east Asia to the Indian ocean. There was much less need for accurate longitude measurement.

As for the main topic (spherical earth), it seems odd that the Chinese would not have known about it at one time or another. Certainly Arab astronomers were aware of it, since they shared the same hellenistic tradition (Ptolemy, Aristotle), and there were many contacts between Chinese and Arab astronomers during the Yuan period and after (Arabs were the "foreign experts" in astronomy before they were supplanted by the Jesuits).

An excellent contribution, and very factually correct.

I think you are spot on in saying that because the Chinese navigated through the Indian Ocean (and therefore through the South China Sea to reach there) they had less pressing need for calculation of longitude since they were rarely exposed to large stretches of open ocean.

The Mediterranean offered the same opportunities for dead reckoning. I am currently reading the Aeneid, and the descriptions of navigation contained there show that this is clear.

Longitude became a pressing issue for those wanting to navigate across the Pacific and Atlantic Ocean.

That said, Gavin Menzies claims that the Chinese had discovered a means of calculating longitude at known latitudes by timing solar eclipses. He has a detailed description of the method in 1421, but I always thought his proof that the Chinese of the time actually knew and used the method a little thin.

[Tibet Libre]

As for the main topic (spherical earth), it seems odd that the Chinese would not have known about it at one time or another. Certainly Arab astronomers were aware of it, since they shared the same hellenistic tradition (Ptolemy, Aristotle), and there were many contacts between Chinese and Arab astronomers during the Yuan period and after (Arabs were the "foreign experts" in astronomy before they were supplanted by the Jesuits).

Yes, it is odd, but not all that unusual. The obvious answer is that Chinese astronomy was not exposed long and hard enough to the new theorem of a round earth. There is a globe in Beijing created by a Persian court astronomer in the 13th century, but no-one apparently paid attention and the Chinese astronomical views of a square earth remained virtually unchanged until the Jesuits rose to high positions much later. And even then, it took 50 to 100 years before the idea took full root in the astronomical community.