Eratosthenes

Astronomy Ancient Greek -276 – -195 354 quotes

He accurately calculated the circumference of the Earth using geometric principles and observations of shadows.

Most quoted

"Give me a lever long enough and a fulcrum on which to place it, and I shall move the world. (Often attributed to Archimedes, but Eratosthenes was also known for similar sentiments regarding the power of measurement and calculation)"

— from Public Address

"To understand the world, one must first measure it. Measurement is not just about numbers; it is about defining boundaries, understanding relationships, and ultimately, comprehending our place within the vastness."

— from Inferred from his scientific methodology

"The Earth is a sphere, and its circumference can be measured. This knowledge, though seemingly practical, reveals the order and the measurable nature of the cosmos, hinting at a deeper, underlying truth."

— from Inferred from his work on Earth's circumference

All quotes by Eratosthenes (354)

The distance to the Moon is 780,000 stadia.

On the Measurement of the Earth (as reported by Macrobius)

The distance to the Sun is 4,000,000 stadia.

On the Measurement of the Earth (as reported by Macrobius)

The Sieve of Eratosthenes is a method for finding prime numbers.

Catastoris (as described by Nicomachus of Gerasa)

He was called 'Beta' because he was second in every field of knowledge.

Suda Lexicon (referring to his nickname)

He was called 'Pentathlos' because he excelled in many fields.

Suda Lexicon (referring to his nickname)

He was called 'Cosmographer' for his work on the world.

General historical understanding of his contributions

He was the first to use the term 'geography'.

Title of his work 'Geographica'

The Earth is divided into five zones: one torrid, two temperate, and two frigid.

Geographica (as reported by Strabo)

He attempted to fix the dates of the Trojan War.

Chronographies (as reported by Clement of Alexandria)

The Earth is a sphere, and its circumference can be measured by observing the sun's shadow at different latitudes.

Summary of his method for Earth's circumference, widely cited

His method for measuring the Earth's circumference was remarkably accurate for his time.

Modern historical assessment of his work

He was a polymath, excelling in mathematics, geography, astronomy, history, and poetry.

General historical understanding of his diverse talents

He served as the chief librarian of the Library of Alexandria.

Historical records of the Library of Alexandria

His work 'Geographica' was a systematic treatise on the world.

Descriptions of 'Geographica' by later authors

He was a student of Callimachus.

Suda Lexicon

He was born in Cyrene.

Suda Lexicon

He died in Alexandria.

Suda Lexicon

His 'Catastoris' contained a catalogue of stars.

References to 'Catastoris' by later authors

He made significant contributions to the field of mathematical geography.

General historical assessment of his work

His work laid the foundation for later geographical studies.

Modern historical assessment of his influence

Contemporaries of Eratosthenes

Other Astronomys born within 50 years of Eratosthenes (-276–-195).