Eratosthenes
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's sphere is no more than a point in comparison with the sphere of the fixed stars.
The moon receives its light from the sun.
Eclipses of the moon occur when it falls into the earth's shadow.
The sun is much larger than the earth.
The fixed stars are immensely far away.
The planets wander among the fixed stars.
The sphere of the heavens revolves from east to west.
The axis of the heavens passes through the poles of the earth.
The celestial equator is the great circle equidistant from the poles of the heavens.
The ecliptic is inclined to the equator.
The solstices are the points where the sun is farthest from the equator.
The equinoxes are the points where the sun crosses the equator.
The tropics are the parallels where the sun turns back.
The Arctic Circle is the parallel where the sun just grazes the horizon at the winter solstice.
Contemporaries of Eratosthenes
Other Astronomys born within 50 years of Eratosthenes (-276–-195).