A Brief History of Geodesy

Summary

The video traces the history of geodesy, starting with an ancient Egyptian named Aatosan, who first measured the Earth's circumference using shadows and geometry. It highlights how geodesy has evolved, enabling the precise mapping of the Earth, understanding its shape, rotation, and distance from the Sun. The script explains the practical applications of geodesy in navigation, exploration, and engineering, leading to the development of railroads and satellite technology. It emphasizes the significance of modern measurements in studying the Earth's changes, showcasing how ancient ideas continue to impact our understanding of the planet today.

Takeaways

• 🌞 Ancient Egyptian mathematician Aatosan discovered that measuring the angle of shadows at different locations could help determine the Earth's circumference.
• 🌍 Geodyssey, the science of measuring and representing the Earth, emerged from these early observations.
• 📐 Triangulation techniques allowed for the accurate mapping of countries and understanding the Earth's shape and size.
• 🌎 The Earth is not a perfect sphere; it is slightly thicker in the middle, as confirmed by expeditions in Peru.
• 🚢 Knowledge of latitude and longitude enabled explorers to navigate oceans and chart unknown territories.
• 🏔️ Engineers used mathematical principles to construct railroads and tunnels that could connect across challenging landscapes.
• 📡 The invention of radio telescopes and satellites revolutionized geodyssey, enabling precise measurements of the Earth's movements.
• 🔭 Scientists can now monitor changes in the Earth's crust, day length, and axial wobble using satellite data.
• 🌊 Laser measurements have improved our understanding of ocean and ice sheet dynamics, including their heights and shapes.
• ⏳ The field of geodyssey has evolved significantly from ancient practices to modern technology, greatly influencing our daily lives.

Q & A

What is geodyssey?

Geodyssey is the science of measuring and representing the Earth, focusing on the location of places and their historical and future movements.

How did Aatosan contribute to geodyssey?

Aatosan, an ancient Egyptian, discovered that by measuring the angle of shadows in one city when the sun was directly above a deep well in another city, one could calculate the circumference of the Earth.

What practical applications arose from the science of geodyssey?

Geodyssey led to the creation of detailed maps, navigation for ships across oceans, and the construction of railroads and tunnels that could meet accurately, even when starting from opposite sides of a mountain.

How did triangulation improve our understanding of the Earth?

Triangulation allowed scientists to determine accurate distances and create detailed maps, enhancing knowledge about the Earth's size, shape, and rotational direction.

What did engineers accomplish with the principles of geodyssey?

Engineers used geodyssey principles to build railroads and tunnels, ensuring they would meet correctly despite the geographical challenges.

How have satellites advanced the field of geodyssey?

Satellites have enabled scientists to measure the Earth's changing size and shape, gravity, and to observe various environmental changes through advanced laser measurements and analysis of their orbits.

What role do radio telescopes play in modern geodyssey?

Radio telescopes are used to make precise measurements of distances between telescopes, aiding in the study of Earth's crust movement and other geological changes.

What were the significant discoveries related to the Earth's shape?

It was discovered that the Earth is not a perfect sphere but is slightly thicker at the equator, a finding that came after expeditions to Lapland, Peru.

How does the historical perspective of geodyssey reflect its evolution?

From the early calculations in ancient Egypt to today's use of satellites, geodyssey has evolved significantly, impacting navigation, mapping, and our understanding of the planet.

What was the initial experiment that led to the birth of geodyssey?

The initial experiment involved measuring the angle of shadows in one city at noon, while the sun was directly above a well in another city, which allowed the calculation of the Earth’s circumference.