Edward Tarbuck, Frederick Lutgens, Dennis Tasa - Earth Science-Pearson (2017)-673-774

Ancient Civilizations and Astronomy

• Record Keeping

  • Ancient Chinese, Egyptians, and Babylonians recorded celestial events.

  • Notable records include the motions of the Sun, Moon, and five planets against fixed stars.

• Predictions

  • Importance of predicting celestial events for societal decisions, e.g., marriage dates.

• Chinese and Halley’s Comet

  • Documented Halley’s Comet for over 10 centuries but did not recognize its periodicity due to long intervals (76 years).

  • Comets often seen as bad omens—associated with disasters like wars and plagues.

• Guest Stars

  • Ancient Chinese recorded appearances of "guest stars," now known as novas or supernovae.

The Golden Age of Astronomy

• Early Greek Contributions (600 B.C.E. - 150 C.E.)

  • Shift from philosophy to observation and data collection.

  • Development of geometry and trigonometry for measuring celestial distances.

• Geocentric Model

  • Greeks proposed a universe with a stationary Earth at the center, surrounded by concentric spheres (geocentric view).

  • Stars are fixed while planets revolve in smaller circles (epicycles) around Earth.

Measurement of Earth

• Shape and Size

  • Early Greeks established the spherical nature of Earth (Aristotle's observations during lunar eclipses).

  • Eratosthenes’ Calculation:

    • Used angles of the noonday sun at different locations (Syene and Alexandria) to calculate Earth’s circumference, resulting in remarkable accuracy for his time.