Babylonian astronomy

Babylonian astronomy was the study of celestial objects during the early history of Mesopotamia. The Babylonians used a numeral system based on 60, called sexagesimal, which made it easier to calculate and record very large or very small numbers, unlike our modern decimal system based on ten.

During the 8th and 7th centuries BC, Babylonian astronomers developed a new empirical approach to studying the heavens. They began to carefully record their observations and use logic to predict movements of planets and stars. This way of thinking was an important step for science and was later adopted by Greek and Hellenistic thinkers. The Babylonians divided the sky into sections and assigned signs to different parts, which helped them track the planets.

Much of what we know about Babylonian astronomy comes from clay tablets that contain astronomical diaries, calculations, and methods. Even though only fragments survive, these show that Babylonian astronomy was the first to use math to describe the movements of the stars and planets. Their work influenced astronomy in the Hellenistic world, India, Islam, and the West.

Old Babylonian astronomy

See also: Babylonian star catalogues

Babylonian astronomers were skilled at watching the sky and recording what they saw. They created special signs called zodiacal signs by dividing the sky into sections. They also made detailed lists of stars and how they moved, using tools like water clocks and shadows to measure time.

The Babylonians were the first to develop a working theory of how planets move. One of their oldest records, the Venus tablet of Ammisaduqa, lists the movements of the planet Venus. They believed that events on Earth could be predicted using signs from the sky, called omens. The MUL.APIN is a key book they wrote that includes information about stars, the movements of planets, and events like eclipses.

Main article: Ancient near eastern cosmology

Main article: MUL.APIN

Neo-Babylonian astronomy

Neo-Babylonian astronomy refers to the study of the stars and planets done by Chaldean astronomers during the Neo-Babylonian, Achaemenid, Seleucid, and Parthian periods in ancient Mesopotamia. These astronomers kept careful records, which helped them notice patterns, such as an 18-year cycle for lunar eclipses called the Saros cycle.

They focused on creating tables, known as ephemerides, to predict where planets and the Moon would appear in the sky. While much of their work was based on simple arithmetic, recent discoveries show they sometimes used geometry as well. One important figure was Seleucus of Seleucia, who supported the idea that the Sun was at the center of the solar system, with the Earth rotating on its axis and orbiting the Sun. Although none of his original writings survive, later writers mentioned his ideas and contributions to astronomy.

Babylonian influence on Hellenistic astronomy

Many ancient Greek writers, including mathematicians, astronomers, and geographers, have preserved works that we still know today. However, for a long time, people forgot about the achievements of earlier civilizations, especially those in Babylonia. Since the 19th century, archaeologists discovered important sites and found many writings on clay tablets about astronomy.

Herodotus noted that the Greeks learned important ideas, such as using a gnomon to tell time and dividing the day into two twelve-hour parts, from the Babylonians. These discoveries show how Babylonian astronomy influenced later Greek thinkers.