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 Earth is not flat.

Implicit in his Earth circumference calculations

He used astronomical observations to solve geographical problems.

Description of his methodology for Earth's circumference

The Sieve of Eratosthenes is an elegant and efficient algorithm.

Modern mathematical assessment of the Sieve

His 'Chronographies' attempted to establish a scientific chronology of historical events.

Descriptions of 'Chronographies' by later authors

He was a pioneer in the systematic study of the Earth.

General historical assessment of his role in geography

His work on the measurement of the Earth was a triumph of ancient science.

Modern historical assessment of his achievement

He combined mathematical rigor with empirical observation.

Analysis of his methodology for Earth's circumference

The concept of latitude and longitude was central to his geographical work.

Descriptions of 'Geographica' by later authors

He attempted to map the known world with greater accuracy.

Goal of his 'Geographica'

His contributions to astronomy were foundational.

General historical assessment of his astronomical work

He was a figure of immense intellectual curiosity.

General biographical understanding

His work represents a high point of Hellenistic scholarship.

Modern historical assessment of the Hellenistic period

I have measured the Earth, and found it to be a sphere, not a flat disk as some still believe.

Diary entry

The sun's rays fall perpendicularly at Syene during the summer solstice, but at an angle in Alexandria.

Correspondence with a student

My method for determining the Earth's size relies on simple geometry and careful observation.

Letter to a patron

To be the second Beta in the world of letters is no small feat, even if some mock the title.

Personal letter to a friend

The library here in Alexandria is a treasure beyond measure. I am fortunate to serve it.

Letter to his mother

Poetry and mathematics are not so different; both seek to find order and beauty in the universe.

Diary entry

I often wonder if future generations will appreciate the precision of our measurements.

Letter to a fellow scholar

The stars hold secrets we are only just beginning to unravel.

Private musings

Contemporaries of Eratosthenes

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