Search results
Oct 7, 2024 · Eratosthenes, Greek scientific writer, astronomer, and poet, who made the first measurement of the size of Earth for which any details are known. He was also the director of the Library of Alexandria. His only surviving work is Catasterisms, a book about constellations.
- The Editors of Encyclopaedia Britannica
- In addition to calculating Earth’s circumference, Eratosthenes created the Sieve of Eratosthenes (a procedure for finding prime numbers), tried to...
- Eratosthenes measured Earth’s circumference mathematically using two surface points to make the calculation. He noted that the Sun’s rays fell vert...
- Eratosthenes died in his 80s in Alexandria, Egypt. He had become blind in his old age and could no longer work by 195 BCE. He reportedly fell into...
- Travel Back in Time
- What Did It Prove?
- When A Fraction Goes A Long Way
- A Few Assumptions Help
- Was He correct?
About 2,250 years ago, there was a man called Eratosthenes. He was one of those ancient Greeks who changed the world. He was a polymath, someone with expert knowledge of a range of topics. A mathematician, geographer, astronomer, philosopher, poet, and music theorist. He's famous for being the first person known to have measured the earth's circumf...
His little experiment demonstrated that the surface of the earth was curved like a sphere. Why? Because his pole in Alexandria was sticking straight into the air but the curvature of the earth made it face slightly away from the sun, causing the pole to throw a small shadow onto the ground. And that allowed him to do something else. Since he knew t...
And that left him with one final measurement. To figure out the circumference of the earth, he needed to somehow measure the distance between Alexandria and Syene. So he asked someone (or a team of people) to walk it. Those people were called "bematists", professional surveyors who were trained to measure vast distances extremely accurately by paci...
Let's go. Assume the earth is a perfect sphere (it's not, but it's not a problem for these calculations). We know there are 360 degrees in a circle. If you cut the earth in half, the earth's great circle will obviously have 360 degrees, and the circumference of that circle (i.e. the total length of its perimeter) could be divided up into equal bits...
He was incredibly close. As it turns out, the meridional circumference of Earth (from pole to pole) is roughly 40,008 km, and the equatorial circumference is about 40,075 km (it's bigger at the equator because Earth slightly bulges in its middle). Not bad for someone with such rudimentary tools. Eratosthenes used his new knowledge to revolutionise ...
- Gareth Hutchens
The Greek scientist Eratosthenes was the first person to calculate Earth’s circumference. He worked as chief librarian of the Alexandrian Library in Egypt and was also known as a writer, an astronomer, a mathematician, and a poet.
Eratosthenes of Cyrene (/ ɛrəˈtɒsθəniːz /; Greek: Ἐρατοσθένης [eratostʰénɛːs]; c. 276 BC – c. 195/194 BC) was an Ancient Greek polymath: a mathematician, geographer, poet, astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria.
Earth is orbited by one permanent natural satellite, the Moon, which orbits Earth at 384,400 km (1.28 light seconds) and is roughly a quarter as wide as Earth. The Moon's gravity helps stabilize Earth's axis, causes tides and gradually slows Earth's rotation .
Aug 14, 2022 · But if a single person gave planet Earth its English name — which is unlikely to say the least — his or her identity has been lost to the sands of time. Still, it's clear that while Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune all started out as the proper names of ancient gods, "Earth" did not.
People also ask
Why is Earth called Earth?
Who was the first person to calculate Earth's circumference?
Why do people call Earth Earth 'Erde' or 'earth'?
Who first coined the name Earth?
What is the best name for Earth?
How old is Earth?
The name Earth is at least 1,000 years old. All of the planets, except for Earth, were named after Greek and Roman gods and goddesses. However, the name Earth is a Germanic word, which simply means “the ground.”
