Roman Astronomy: How did Romans See the Planets

Our understanding of the universe's structure and origins is known as cosmology, a term derived from Greek. Prior to the advent of telescopes, humans relied solely on their senses to form a picture of the cosmos. Ancient civilizations developed cosmological models that combined their direct observations of the skies with extensive philosophical and religious symbolism.

Three thousand years ago, people believed that the Earth was supported by massive pillars. They thought the sun rose in the east every morning, traveled overhead, and set in the west each evening, then passed under the Earth during the night to reappear in the east the next morning.

This view of the universe was challenged by Pythagoras around 500 BCE, when he proposed that the Earth was spherical and that the sun circled it daily from east to west. By the second century BCE, this idea had been around for about 400 years and was further developed by Hipparchus, the renowned Greek scientist.

The Romans inherited much of their astronomical knowledge from the Greeks, especially the works of figures like Ptolemy, Hipparchus, and Aristotle. Roman astronomy was largely practical, focusing on the calendar and timekeeping for agricultural, civic, and religious purposes.

Is the Earth round or flat?

Educated individuals in the eastern Mediterranean region recognized Earth's round shape at least 2000 years before Columbus. This understanding may trace back to Pythagoras, who, 2500 years ago, proposed that Earth was spherical due to his belief that circles and spheres were "perfect forms."

Greek scholars like Aristotle, who lived between 384–322 BCE, documented these ideas, explaining that the Moon’s phases result from viewing different parts of its sunlit side and that lunar eclipses revealed Earth's round shadow. Aristotle also noted that travelers heading south saw new stars and that the North Star's height decreased, indicating a curved Earth surface.