History of Astronomy and Early Cosmology

Astronomy and cosmology are fields of science and knowledge that study the cosmos and the universe. Cosmology, in particular, is part of theoretical physics and investigates the origin, nature, and evolution of the universe.

Prehistoric Sky Observation

Cosmology was observed for the first time in prehistory, reflecting humanity's early interest in observing the sky during prehistoric epochs.

The development of calendars, linked to tracking animal migrations and agricultural cycles, provides evidence of systematic attempts to determine the position and movements of the Sun and the Moon.

Stonehenge demonstrates the study of the universe in order to try to determine with maximum precision the position of the Sun during the summer and winter solstices.

Astronomy in Urban Civilizations

Civilizations like Babylon and Egypt observed the sky on a regular basis.

The need for precise timekeeping to organize agriculture and urban activities led to the emergence of professional sky observers in these civilizations and the Near East.

These observers often belonged to the priestly caste and were responsible for the emergence of the pseudoscience of astrology.

Babylonian Astronomy

• Babylonian priests used rudimentary methods to locate celestial bodies and created early constellation maps.
• They discovered a number system in base 60.
• They measured the movements of the Moon and Sun.
• They created a lunar calendar, which was later replaced by a solar calendar of 365 days.

They were not able to build a figurative representation of the universe.

Egyptian Astronomy

• Egyptian priests and astronomers watched the stars and also measured their positions to elaborate calendars.
• They also developed rudimentary geometry.

However, they were not able to develop a comprehensive cosmology.

Ancient Greek Astronomy

The Greeks were the natural heirs to the cultural traditions of the Egyptians and Babylonians. The non-priestly character of their religion facilitated the emergence of philosophy.

Early astronomers were also philosophers. They sought to determine things like:

• The shape of the Earth
• Why the Earth does not fall
• What the stars are
• Eclipses and Moon phases

In the 5th century BC, Anaxagoras of Clazomenae witnessed the fall of a meteorite. He stated that they were 'fiery stones from the Sun and Moon' and explained the mechanics of eclipses correctly.