1. What evidence did ancient Greek astronomers have that Earth does NOT move?
The answer is because of the lack of parallax, but then there's a follow-up question...
2. How do we knoew it DOES?
To answer the question of how we know that the Earth does move, we rely on modern scientific understanding and evidence. In contrast to ancient Greek astronomers who believed the Earth was stationary, several lines of evidence support the concept of Earth's motion. Here is how we know that the Earth moves:
1. Observations of celestial bodies: The phenomenon of stellar parallax, which was notably absent in ancient Greek astronomy, provides evidence of Earth's motion. As the Earth orbits the Sun, nearby stars appear to shift their position against the more distant background stars over the course of a year. This parallax effect is observed and measured by astronomers, indicating that the Earth is in motion.
2. Corroborating astronomical observations: Observations of other planets in our solar system also provide evidence for Earth's movement. By studying the positions and motions of other planets, scientists can calculate their orbits based on the laws of motion discovered by Isaac Newton. These calculations confirm that the Earth is a moving body in our solar system.
3. Experimental evidence: The Foucault Pendulum is an apparatus that demonstrates the Earth's rotation. It consists of a long pendulum swinging back and forth in a fixed plane. As the Earth rotates, the plane of the pendulum's swing appears to rotate slowly over time. This phenomenon is consistent with Earth's rotation and has been observed in experiments.
4. Space exploration: The ability to send satellites and spacecraft into space has provided direct evidence of Earth's motion. Spacecraft, such as the Apollo missions to the Moon, have captured images and data showing Earth from different perspectives. These observations clearly show the Earth rotating on its axis and orbiting the Sun.
Overall, the combination of observational, experimental, and technological advancements in astronomy and space exploration has provided us with ample evidence that the Earth moves. As scientific knowledge progresses, our understanding of Earth's motion continues to deepen and refine.