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Geodesy

Space Geodetic Techniques

From Quasars to Coordinates: How VLBI Measures Earth’s Shape and Motion

From Quasars to Coordinates: How VLBI Measures Earth’s Shape and Motion

Imagine determining the position of a point on Earth with millimeter precision using radio signals from celestial objects billions of light-years away. This may sound like science fiction, but it is exactly what Very Long Baseline Interferometry (VLBI) allows scientists to do. What is VLBI? Long before satellites and digital maps, people looked to the sky and used celestial objects—most commonly t ...[Read More]