Astronomy Origins in Ancient Greece | Astronomy Masters Program

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Back in ancient Greece, before modern technological structures were built to measure the skies, careful observations had to be made and repeated over and over to ensure their accuracy. Careful, repeatable observations also underlie modern science. Elements of modern science were therefore present in many early human cultures.

The path that led to modern science emerged from the ancient civilizations of the Mediterranean and the Middle East—especially from ancient Greece.

Why does modern science trace its roots to the Greeks?

Greece gradually rose as a power in the Middle East beginning around 800 b.c. and was well established by about 500 b.c. Its geographical location placed it at a crossroads for travelers, merchants, and armies from northern Africa, Asia, and Europe and Building on the diverse ideas brought forth by the meeting of these many cultures, ancient Greek philosophers soon began their efforts to move human understanding of nature from the mythological to the rational.

Greek philosophers developed at least three major innovations that helped pave the way for modern science. First, they developed a tradition of trying to understand nature without relying on supernatural explanations and of working communally to debate and challenge each other’s ideas. Second, the Greeks used mathematics to give precision to their ideas, which allowed them to explore the implications of new ideas in much greater depth than would have otherwise been possible. Third, while much of their philosophical activity consisted of subtle debates grounded only in thought and was not scientific in the modern sense, the Greeks also saw the power of reasoning from observations. They understood that an explanation could not be right if it disagreed with observed facts.

Greek philosophy first began to spread widely with the conquests of Alexander the Great. Alexander had a deep interest in science, perhaps in part because Aristotle (who we’ll touch on later) had been his personal tutor. Alexander founded the city of Alexandria in Egypt, and his successors founded the renowned Library of Alexandria. Though it is sometimes difficult to distinguish fact from legend in stories of this great Library, there is little doubt that it was once the world’s preeminent center of research, housing up to a half million books written on papyrus scrolls. Most were ultimately burned, their contents lost forever.

So, As European civilizations fell into the period of intellectual decline known as the Dark Ages, scholars of the new religion of Islam sought knowledge of mathematics and astronomy in hopes of better understanding the wisdom of Allah. Around a.d. 800, the Islamic leader Al-Mamun established a “House of Wisdom” in Baghdad, where Islamic scholars—often working together with Jews and Christians—translated and thereby saved many ancient Greek works. These scholars were also in frequent contact with Hindu scholars from India, who in turn brought ideas and discoveries from China. Hence, the intellectual center in Baghdad achieved a synthesis of the surviving work of the ancient Greeks and that of the Indians and the Chinese. Using all these ideas as building blocks, scholars in the House of Wisdom developed the mathematics of algebra and many new instruments and techniques for astronomical observation. For this reason, many official star names come from Arabic; for example, the names of many bright stars begin with al- which means “the” in Arabic.

But, let’s go back to Greece in the beginning. We generally trace the origin of Greek science to the philosopher (THEY-leez) Thales. Thales was the first person known to have addressed the question “What is the universe made of?” without resorting to supernatural explanations. While he thought the earth was flat, everyone thought he was wrong, because he was.

A more sophisticated idea followed soon after, proposed by a student of Thales named AnAXimander. AnAXimander suggested that Earth floats in empty space surrounded by a sphere of stars and two separate rings along which the Sun and Moon travel. We therefore credit him with inventing the idea of a celestial sphere. But even he had his flaws, thinking the Earth was more cylindrical than spherical.

We do not know precisely when the Greeks first began to recognize Earth as round, but this idea was taught as early as about 500 b.c. by the famous mathematician Pythagoras. He and his followers may have adopted a spherical Earth in part because they considered a sphere to be geometrically perfect.