Ancient Greece was famous for its smart and talented scientists, writers, philosophers, and mathematicians. Each of them took a worthy place in the historical chronology. What he became famous for, and for what merits he was, Eratosthenes is highly valued and respected in scientific circles, you will learn from the biography of the scientific thinker.

Eratosthenes, an outstanding mathematician, founder of physical geography, astronomer and philologist Eratosthenes, occupies a worthy place in the galaxy of great scientists of antiquity. Thanks to his versatile interests and hobbies, he made a tangible contribution to the development of not only the exact sciences, but also to more subtle cultural spheres. For his many-sided activity, he was endowed by his contemporaries with the nickname Pentatle, in other words, a pentathlete. Eratosthenes is also known under a different pseudonym, Beta, meaning "second". It in no way detracts from the merits of Eratosthenes, but characterizes him as a scientist who achieved, if not the highest, but excellent results. How did Eratosthenes deserve such close attention to his person, what scientific discoveries and creative victories did he gain during his existence? Let's look into the past and make a short excursion into the biography of Eratosthenes.

Eratosthenes was born in 275 BC. in Africa in the city of Cyrene, one of the most significant and great cities of antiquity. He went to receive his first knowledge in Alexandria, and then moved to Athens. Among the famous mentors and inspirers were: the poet Callimachus, the grammarian Lysanias, the Stoic philosopher Ariston and the Platonist Arcesilaus. A huge creative potential, an inexhaustible desire to learn everything new and unknown, a wide range of interests and a versatile education allowed Eratosthenes to declare himself as an inquisitive, educated and enthusiastic person. These valiant merits could not go unnoticed and approx. 245 BC Eratosthenes was personally invited by Ptolemy III to Alexandria to combine the two posts. He simultaneously brought up the successor to the throne and headed the Library of Alexandria. His scientific work and achievements were highly valued by his associates and contemporaries. For example, Archimedes wrote a book about him called Ephodic (Method).

Not all the creative opuses of Eratosthenes have survived to this day, something has already sunk into oblivion, and something has come down only in fragments. In many sciences, he made important and unique discoveries, which are worth mentioning and briefly describing the most significant of them.

So, the mathematical writings of Eratosthenes have not been completely preserved, all that contemporaries know about is the treatises “On Doubling the Cube” and “On the Mean”. The scientist invented a simple mechanical mesolabial device, its purpose was to extract cube roots. But perhaps the most striking and outstanding discovery can be considered the sieve of Eratosthenes. This is a phenomenal way, the meaning of which is to determine any number of ordinal primes that do not exceed some integer.

In the field of scientific geography, the ancestor of which is Eratosthenes, a lot of discoveries and inventions also remained. His Geography of three volumes contains descriptions of chronicles, finds, highlights the difficulties of the material and technical plan relating to geography. Of particular note is his treatise "On the Measurement of the Earth", which popularly outlines the method of determining the size of the globe. The method was based on a synchronous measurement of the range of the Sun in Syene and Alexandria, which are practically on the same meridian, during the summer solstice. Eratosthenes was well aware that the Earth is a sphere, and he was able to calculate its circumference. The measurement results turned out to be incredible - the diameter of the Earth differed from the true polar one by only 80 km down.

Unfortunately, through the millennia, the map drawn by Eratosthenes has not yet been able to reach, but according to the surviving descriptions, it is easy to reproduce it. The descriptions contain detailed information on the passage of parallels and meridians, as well as the distances between the lines in stages (Egyptian stages equals 157.7 meters). And here are a few conclusions and conclusions made by Eratosthenes:
- Rhodes served as a starting point, respectively, to the south of Rhodes, he designated the "southern" countries, and to the north - the "northern" ones;
- one of the channels of the Danube flows into the Adriatic Sea;
- The Strait of Gibraltar (in ancient times, the Pillars of Hercules) was formed during the Trojan War;
- Thule, the northernmost point, was part of the Norwegian coast. The territory north of Thule was considered absolutely uninhabitable;
- the border between Europe and Asia was designated Tanais (the current Don);
- at the latitude where Taproban Island (present-day Sri Lanka) is located, it is so sultry that the southern borders of the island are uninhabited.

Eratosthenes is deservedly considered the founder of scientific chronology. Creating his Chronographies, he made an attempt to determine the dates that are directly related to the political and literary era of Ancient Greece. He compiled a list of the victors of the Olympic Games and accurately developed a chronological table, where all significant events were dated according to the Olympiads, that is, four-year periods.

Of the works on astronomy, only Catasterisms survived - a list of constellations and their constituent stars without indicating their locations. Eratosthenes conducted his astronomical observations with the help of an armillary sphere, a device that determines the coordinates of heavenly bodies.

As a literary critic and philologist, Eratosthenes declared himself in the work "On Ancient Comedy", where he analyzed the works of Athenian writers. He created the poem "Hermes", which vividly and colorfully describes the fate of God, starting from the birth and ending with death, his glorious deeds and adventures. Another famous creation of his pen is the epic "Hesiod", dedicated to the tragic death of the poet, and the heavenly punishment that fell on his killers.

Eratosthenes' contribution to the development of geography, the great Greek mathematician, astronomer, geographer and poet is outlined in this article.

Eratosthenes' contribution to geography. What did Eratosthenes discover?

The scientist was a contemporary of Aristarchus of Samos and Archimedes, who lived in the 3rd century BC. e. He was an encyclopedic scholar, library keeper in Alexandria, philosopher, correspondent and friend of Archimedes. He also became famous as a surveyor and geographer. It is logical that he should summarize his knowledge in one work. And what book did Eratosthenes write? They would not have known about it if it were not for Strabo's Geography, who mentioned it and its author, who measured the circumference of the Earth's globe. And this is the book "Geography" in 3 volumes. In it, he outlined the foundations of systematic geography. In addition, the following treatises belong to his hand - “Chronography”, “Platonist”, “On Averages”, “On Ancient Comedy” in 12 books, “Revenge, or Hesiod”, “On Elevation”. Unfortunately, they came to us in small snatches.

What did Eratosthenes discover in geography?

The Greek scientist is rightfully considered the father of geography. So what did Eratosthenes do to earn this honorary title? First of all, it is worth noting that it was he who introduced the term “geography” in its modern sense into scientific circulation.

He owns the creation of mathematical and physical geography. The scientist suggested the following assumption: if you sail west from Gibraltar, then you can reach India. In addition, he tried to calculate the size of the Sun and the Moon, studied eclipses and showed how the length of daylight hours depends on geographical latitude.

How did Eratosthenes measure the radius of the earth?

In order to measure the radius, Eratosthenes used calculations made at two points - Alexandria and Syene. He knew that on June 22, on the day of the summer solstice, the heavenly body illuminates the bottom of the wells at exactly noon. When the Sun is at its zenith in Syene, it is 7.2° behind in Alexandria. To get the result, he needed to change the zenith distance of the Sun. And what tool did Eratosthenes + use to determine the size? It was a skafis - a vertical pole, fixed at the bottom of a hemisphere. Putting it in a vertical position, the scientist was able to measure the distance from Syene to Alexandria. It is equal to 800 km. Comparing the zenith difference between the two cities with the generally accepted circle of 360 °, and the zenith distance with the circumference of the earth, Erastosthenes made a proportion and calculated the radius - 39,690 km. He was mistaken by just a little, modern scientists have calculated that it is 40,120 km.

Education

What did Eratosthenes discover and in what year?

In the third century BC, sciences were in their infancy, and the term scientific thinking was not yet known to mankind. However, numerous Greek researchers have already begun to raise questions about how the world works around them, while others indulge in wars or political intrigues.

What Eratosthenes Discovered: Briefly

The Greek mathematician, astronomer and geographer entered history, and not only scientific, but also world history, as the first person who not only asked the question about the size of the Earth, but also as a scientist who managed to answer this question.

By the time Eratosthenes became a youth, the Academy was actively operating in Alexandria, producing universal sages who knew a lot about numerous sciences, history and poetry. The future explorer of the Earth received his first education from one of the most famous poets of his time - Callimachus. I must say that Eratosthenes carried his love for literature through his whole life, calling himself a philologist to the last.

However, his contribution to science is not limited to philological studies, but also extends to geography, mathematics and music. The scientist paid much attention to the geography of Egypt, where he spent most of his life and where he ended his days.

Scientific biography of Eratosthenes

What did Eratosthenes discover? This discovery left its mark on all subsequent science and culture. It seemed impossible, but he still measured the Earth. Such significant perseverance and abilities of the scientist were also helped by the fact that after Alexandria he continued his studies in Athens at the famous Platonic Academy, after which he considered himself a Platonist.

However, in 245 BC, the Athenian period ended, as a young famous scholar received an invitation to move to Alexandria to begin work in the illustrious Library of Alexandria. In these educational institutions, his widest range of interests and encyclopedic erudition were formed.

On guard of knowledge

It will be interesting for the 7th grader to learn about what Eratosthenes discovered in geography, also because this scientist is rightfully considered one of the men who, with his own efforts, designed a number of scientific areas and branches of knowledge that contributed to the glory of the Library of Alexandria.

For example, it was under Eratosthenes that entire departments were created in the library, whose employees were engaged in the census and study of great Greek poets such as Aeschylus, Sophocles, Euripides and, of course, Homer.

Such a wide range of interests and uncontrollable energy caused Eratosthenes to be given several honorary nicknames, the most common among which were "pentathlete", which indicated his all-round development, and "beta", which testified to the deepest reverence that contemporaries had for the great philologist, recognizing behind him the status is so high that only Plato was ahead of him.

Scientific works: mathematics

Of the works devoted to mathematical problems, only a letter addressed to King Ptolemy, in which the scientist talks about the doubling of the cube and describes an instrument that entered the history of science called the mesolabium, has survived in its entirety.

We can judge other mathematical works and what Eratosthenes discovered in mathematics only by fragmentary information from third-party sources, such as the works of Pappus and Eutocius, one of which refers to the work of a senior colleague, and the second quotes Eratosthenes altogether.

There is, however, one rather curious work, about which European science learned from the follower of the middle Platonism, Theon of Smyrna. In his work, the medieval scholar mentions the work "Platonist", in which Eratosthenes discusses the proportions and relations of equality.

It is worth noting that the works of the scientist were extremely popular with the followers of Platonism in the lll century AD. For example, Nicomachus of Geras, known as a mathematician and music theorist, in his essay "Introduction to Arithmetic" quite extensively quotes an unknown work of Eratosthenes, using his name as an undeniable authority both in mathematics and in harmony and poetics.

Speaking about what Eratosthenes discovered and in what year, one cannot fail to mention the so-called sieve of Eratosthenes, which is an algorithm for finding a prime number in any predetermined limit.

Astronomy and geography

Unfortunately, only one of the astronomical works has survived to this day - "Catasterisms", in which the scientist tries to calculate the constellations and stars that make up them. In total, about seven hundred objects are mentioned in the text.

Eratosthenes loved geography so much that he allowed himself to disagree with Homer himself, declaring that the world described in the Odyssey cannot exist in reality. Sometimes he is even called the father of geography, since he was the first to apply the scientific method to measuring the size of the Earth, combining his vast knowledge of astronomy and geography, as well as mathematics.

Arguing for a long time about world harmony, the relationship between outer space and the earth, Eratosthenes comes to the conclusion that Syena and Alexandria lie on the same meridian. On this basis, he calculated the distance separating the two settlements, and then gave data on the estimated diameter of the Earth.

According to calculations, it was 252,000 stadia, which was approximately equal to 6,287 km. Such a calculation today can be considered quite accurate, since, according to modern information, the average diameter of the Earth is approximately 6,371 km.

Historical criticism of geography

It is worth saying that it was he who began to use parallels and meridians in order to establish a connection between all places in the world. Such an approach, according to Eratosthenes, should have eliminated the obvious shortcomings in the work of his predecessors.

He considered worthy of correction not only the data cited by Homer, but also the scientists who were his closest ancestors. They, as you know, taking advantage of the campaigns of Alexander the Great, made a description of the eastern lands and peoples.

However, these data were criticized in an essay on geography, which Eratosthenes divided into three volumes. As is known today from the writings of Strabo, Eratosthenes received the title of father of geography not only for bold and productive ideas, but also for the creation of the very term "geography", which can be translated as "earth description".

What did Eratosthenes discover?

Having understood in detail the contribution that the great Greek made to the development of science and the arts, it is worth summarizing all his activities, which had a significant impact on the formation of the scientific way of thinking in European civilization.

Here is a list of what Eratosthenes discovered in geography and in what year:

• The sun's rays are parallel.
• Siena lies in the Tropic of Cancer.
• Alexandria is separated from Syene by 5,000 stadia.
• The earth is a perfect sphere.

Unfortunately, it is not possible today to establish the exact dates when these discoveries were made, however, scientists know for certain that Eratosthenes was born in Cyrene in 276 BC, and died in 194 BC. e.

Historical reference

The future theorist was born around 276 BC. in the ancient city of Cyrene, famous in the past, on the site of which the Libyan Shahhat is located today. It is worth recalling that, despite the accepted name Ancient Greece, there was no single state as such in history. Despite this, united by a common language, complementary forms of polytheism and asceticism in the emerging sciences, the Greeks constituted a single geopolitical space. Greeks are not a nationality, but a combination of many qualities that give the right to bear this title. Eratosthenes received a good education, in addition, he was noticeably carried away by the philosophy of Plato. Becoming a student of this school - the longest in history, which lasted about a thousand years, Eratosthenes was forced to take up mathematics. This scientific discipline, along with geometry, was a kind of pass, a preparatory stage for the process of becoming a true philosopher. Without becoming in the future a person thinking ontologically, not thinking about the root causes of being, Eratosthenes made a practical proof of the sphericity of the Earth. Today, this generally accepted norm is not surprising, but the mythological concept of that time made it possible to live in a world of fairy tales and fantasies. What does the world look like, what is its form, what is the order in it - the mythology of Ancient Greece did not give answers to these questions.

It is known for certain that for his merits as a scientist, around 255 BC. Eratosthenes became head of the Library of Alexandria. This lost treasure of knowledge of the ancient world still haunts bibliophiles, scientists and simply lovers of antiquity today. Having become such a significant person, Eratosthenes proved his chosenness. He found a way to confirm the sphericity of the planet and calculate the magnitude of its diameter.

Significance for modern times

Drawing attention to the fact of the difference in the angle of the shadow in the sundial installed in different cities, Eratosthenes came to a conclusion that was brilliant in its simplicity. If we take into account the theoretically correct conclusion about the sphericity of the Earth, then to calculate its diameter it is enough to conduct a small experiment. Knowing that the cities of Alexandria and Sien (Egyptian Aswan in our time) are located approximately on the same line from north to south, Eratosthenes measured the angle of incidence of the shadow in the solar chronoscope at noon. In Siena, the sun is almost at its zenith, which makes the task much easier. Having drawn a circle and painted over a sector in it, the angle of which is equal to the angle of incidence of the shadow in Alexandria, it remains to carry out simple calculations. Thanks to the travelers of that time, the distance between these Egyptian cities was known. It was taken for 800 kilometers. Further, everything is simple. Taking the profile of the Earth as a circle, the length of the remaining unshaded sector and, accordingly, the diameter of our planet are calculated. According to the calculations of Eratosthenes, the length of the circle was 40,000 km (40,075 km according to modern data). Calculating the radius was also not difficult.

But the mathematician did not stop there. He introduced such auxiliary concepts in geodesy and cartography as meridians, parallels, latitude and longitude. Today it is impossible to imagine a modern geophysical map without them. Such a powerful breakthrough in cartography at that time could not be applied in practice, but today the accuracy of the location of the object, its geographical coordinates are a necessity. Aviation, maritime communications, the possibility of satellite car navigation - this is not a complete list of the applied values ​​of the discovery of Eratosthenes. More developed than civilization itself, moving away from a primitive understanding of nature to scientific thinking - this is the main achievement of this mathematician.

Conclusion

It is believed that the old age of a genius was tragic. He died in 194 BC, having lost his position as head of the library, and besides, he was blind. Eratosthenes died of starvation, but probably not from lack of money, but as a rather cruel way of suicide. The second revolutionary in the world of cartography was Gerhard Mercator, a resident of the Holy Roman Empire.

A brief biography of Eratosthenes will tell you who Eratosthenes is and what he did.

Eratosthenes short biography

E ratosthenes of Cyrene (276 BC-194 BC) - Greek mathematician, astronomer, geographer, philologist and poet. The first known scientist to calculate the size of the Earth.

Eratosthenes received his primary education in Alexandria under the guidance of his fellow countryman. callimacha. Another teacher of Eratosthenes in Alexandria was the philosopher Lysnius. After moving to Athens, he became so close to the school of Plato that he usually called himself a Platonist. The result of the study of the sciences in these two centers was the encyclopedic erudition of Eratosthenes; in addition to writings on mathematical sciences, he also wrote treatises “on good and evil”, on comedy, etc. Of all his works, Eratosthenes attached particular importance to literary and grammatical ones, as can be concluded from the fact that he liked to call himself a philologist.

In 245 BC. King Ptolemy III Euergetes invited Eratosthenes to Athens to work in the Library of Alexandria, where his teacher Callimachus and Apollonius of Rhodes were already working. Eratosthenes responded to the invitation, at the age of about thirty he came to Alexandria, where he remained until his death. Five years after his arrival, he succeeded Apollonius of Rhodes as head of the Library of Alexandria. As head of the library, Eratosthenes taught the children of the monarch - the future ruler Ptolemy IV and his sister (and later wife) Arsinoe.