Science Common Sense

1812 - How did humans come to understand the size and shape of the Earth through various scientific methods?

Imagine going on a journey to learn about the Earth's size and shape. Here's how humans figured it out:

1. Shadow observation ( ancient Greece, 500 BC): Philosopher Eratosthenes noticed that at the same time of day, the sun's shadow was different in two cities (Syene and Alexandria). This told him that the Earth was round.

2. Circumnavigation (1400s-1500s AD): When sailors traveled around the world, they realized that the Earth was spherical in shape.

3. Stellar observations ( ancient Greece): By studying the stars, scientists found that the constellations in the sky changed as they moved north or south. This helped them understand the Earth's shape.

4. Measuring the horizon ( ancient Greece): By observing how far ships sailed before disappearing over the horizon, scientists calculated the Earth's curvature.

5. Satellites and space exploration (1950s-60s AD): Launching satellites and space missions allowed humans to see the Earth from space and directly measure its size and shape.

Scientific methods and observations helped us slowly piece together the truth about our planet.