Physical geodesy

Physical geodesy is the science of measuring the size and shape of Earth, and how it changes over time. To do this, geodesists measure things like the distance between two points on the Earth's surface, the angle between three points on the surface, and the tilt of the surface. They also measure how fast Earth's surface is moving and how gravity varies across the planet. All of these measurements help us understand how Earth works, and how it might change in the future.