SUMMARY
The diameter of Earth cannot be measured directly using rulers; instead, methods such as Eratosthenes' calculation and the Struve Geodetic Arc provide historical approaches to estimate it. For measuring other celestial bodies, techniques like occultation are employed, where the timing of a radio signal from an orbiting probe is analyzed as it passes behind a planet. This method is also applicable to asteroids, which can be sized through stellar occultation by observing the cut-off time of a star's light as the asteroid eclipses it.
PREREQUISITES
- Understanding of Eratosthenes' method for calculating Earth's circumference
- Familiarity with the Struve Geodetic Arc and its historical significance
- Knowledge of occultation techniques in astronomy
- Basic principles of celestial mechanics and light propagation
NEXT STEPS
- Research Eratosthenes' method for calculating Earth's diameter
- Explore the Struve Geodetic Arc and its implications for geodesy
- Learn about the technique of stellar occultation for measuring celestial bodies
- Investigate the principles of radio signal timing in planetary measurements
USEFUL FOR
Astronomers, geodesists, educators in Earth sciences, and anyone interested in the methodologies for measuring planetary diameters.