Here's why:
* Ancient astronomers were primarily focused on observation and measurement. Their primary concern was to understand the motions of celestial bodies, predict eclipses, and develop calendars.
* Philosophical ideas influenced their interpretations. The notion of a perfect, unchanging heaven was a common theme in Greek philosophy (particularly Plato and Aristotle), and it resonated with astronomers. This philosophical framework led them to interpret celestial movements as being driven by perfect, circular motions.
* The Earth's imperfection was a consequence of their observations. They noticed the Earth's imperfections (mountains, valleys, changing seasons) and contrasted them with the seemingly unchanging perfection of the stars and planets.
Here's how this assumption affected ancient astronomy:
* Geocentric model: The idea of a perfect, unmoving Earth at the center of the universe was a direct consequence of the philosophical assumption of Earth's imperfection.
* Perfect circular motions: Ancient astronomers believed that celestial bodies moved in perfect circles because circles were considered the most perfect geometric shape.
* Emphasis on mathematical harmony: The focus on perfect, unchanging heavenly bodies led to the development of complex mathematical models to explain their movements.
However, it's important to remember that ancient astronomy was not monolithic. Not all ancient astronomers embraced this philosophical assumption. For example, some ancient Greek thinkers like Aristarchus of Samos proposed heliocentric models, suggesting the Earth revolved around the Sun.
In summary, the concept of a perfect heaven and corrupt Earth was a philosophical assumption that significantly influenced ancient astronomy. However, it's crucial to acknowledge the diversity of thought among ancient astronomers and the fact that their primary focus was on observation and measurement.
