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The Greeks never saw this view of the earth from space!

The earth in Greek astronomy: The Greeks never saw this view of the earth from space!

Gaia and the Earth

Early Greeks thought of the Earth as the goddess Gaia, the mother of everything. Like a mother, the Earth gave food to people.

Who’s the goddess Gaia?
How old is the Earth?
More Greek religion
More Greek astronomy
All our ancient Greece articles

By the time of Homer’s Odyssey, Greek sailors knew the outline of the Mediterranean and the Black Sea quite well, and they knew something about the Red Sea, the Persian Gulf, and the Arabian Peninsula.

What’s the Odyssey?
Greek ships and sailing
The Arabian Peninsula

The earth is round

Two hundred years later in the Classical period, while some people still believed the earth was flat, educated Greeks like Thales knew that the earth was a round ball.

The astronomer Thales
Who was Herodotus?

Herodotus, in the 400s BC, knew that some people thought the ocean went all the way around Eurasia and Africa, though he wasn’t sure this was right. Herodotus had heard stories that some people had sailed all the way around Africa, too. He knows that it’s very cold in the north, and snows a lot.

He knew the rivers of Eastern Europe and Ukraine: the Danube, the Dniester, the Bug, the Dnieper, the Inhul, the Molochna, and the Don, and further east: the Tigris and Euphrates, the Oxus, the Jaxartes, and the Indus.

The earth goes around the sun

Aristarchus, about 300 BC in the Hellenistic period, used his observations of the eclipse of the moon to prove that the earth went around the sun instead of the sun going around the earth.

Aristarchus of Samos
Egyptian science and math
History of astronomy

Aristarchus also calculated that the sun must be much bigger than the earth and the moon, and that the stars must be very, very far away. Most other astronomers were skeptical of Aristarchus’ ideas, even though they all turned out to be right. To the Greeks, who always placed man at the center of everything, it was hard to change that idea.

Measuring the circumference of the earth

Finally, by about 200 BC, Greek-speaking scientists working in Egypt like Eratosthenes were able to use astronomy and geometry to measure the circumference of the earth (the distance around it).

Eratosthenes and astronomy

Did you find out what you wanted to know about the earth in Greek astronomy? Let us know in the comments!

Learn by doing: observe a lunar eclipse
Greek ideas about the Moon

Bibliography and further reading about Greek astronomy and the Earth:

The Librarian Who Measured the Earth, by Kathryn Lasky (1994). An account of the life and work of Eratosthenes, who figured out the circumference of the earth. Explains how he did it. Easy reading.

Greek Astronomy, by Thomas Heath (1932). A collection of what ancient Greek writers had to say about astronomy, in their own words, with a long introduction. For adults.

The History & Practice of Ancient Astronomy, by James Evans (1998). Includes both the history, and directions to actually re-do the experiments that ancient Greek astronomers used to figure out their conclusions. For adults.

Greek Science After Aristotle, by G. E. R. Lloyd (1975).

More about Roman astronomy (Ptolemy)
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