Eratosthenes

Definition

Eratosthenes was a Greek mathematician, astronomer, and geographer who is best known for calculating the circumference of the Earth with remarkable accuracy in the 3rd century BCE. His work represents a significant advancement in ancient science and geography, showcasing the intellectual achievements of Ancient Greece and its contributions to understanding the world.

5 Must Know Facts For Your Next Test

1. Eratosthenes served as the chief librarian at the Library of Alexandria, one of the most significant centers of learning in the ancient world.
2. He devised a method to measure the Earth's circumference by comparing the angle of the sun's shadow in two different locations during the summer solstice.
3. His estimate of the Earth's circumference was about 39,375 kilometers (24,662 miles), which is surprisingly close to modern measurements.
4. Eratosthenes was also known for his work in chronology, where he created a timeline that helped establish dates for historical events.
5. His contributions laid the groundwork for future geographic exploration and scientific inquiry, influencing scholars for centuries to come.

Review Questions

• How did Eratosthenes calculate the circumference of the Earth, and why is this calculation significant?
  • Eratosthenes calculated the circumference of the Earth by measuring the angle of shadows cast by sticks in two different locations in Egypt during the summer solstice. He noted that at noon in one city, there was no shadow while in another city some distance away, a shadow was cast. By using geometry to determine the angle difference and knowing the distance between the two cities, he could estimate the Earth's size. This calculation was significant as it demonstrated early scientific reasoning and set a precedent for future geographic studies.
• Discuss Eratosthenes' contributions to geography and how they influenced later scientific thought.
  • Eratosthenes made substantial contributions to geography by creating one of the earliest known maps that included latitude and longitude. His systematic approach to measuring distances and mapping land features laid foundational principles for modern geography. His works influenced later scientists and explorers who expanded upon his methods, fostering an environment that encouraged exploration and improved understanding of Earth’s geography in subsequent centuries.
• Evaluate the impact of Eratosthenes' work on both mathematics and geography in Ancient Greece and beyond.
  • Eratosthenes' work had a profound impact on both mathematics and geography. His calculations regarding Earth's circumference not only showcased advanced mathematical skills but also represented a significant achievement in empirical science during Ancient Greece. Additionally, his development of a systematic approach to mapping established key concepts that guided future explorers and geographers. This influence extended well beyond his time, inspiring scholars throughout history to continue exploring and understanding our planet with scientific rigor.

Related terms

Circumference: The distance around a circle, which Eratosthenes calculated for the Earth using a method based on shadows and angles from two different locations.

Geography: The study of the Earth's physical features, environment, and human activity, which Eratosthenes contributed to by creating one of the earliest maps and defining latitude and longitude.

Prime Numbers: Numbers greater than 1 that have no positive divisors other than 1 and themselves; Eratosthenes also devised the Sieve of Eratosthenes, an algorithm for identifying prime numbers.