Which Dutch geophysicist and geodesist invented a precise method for measuring gravity at sea, leading to gravity anomalies above the ocean floor and attributing them to continental drift?

• A. Felix Andries Vening Meinesz
• B. Heike Kamerlingh Onnes
• C. Hendrik Lorentz
• D. Christiaan Huygens

Answer: (A)

Measuring gravity at sea is hard because a moving ship introduces many accelerations that mask the true vertical gravity signal. Felix Andries Vening Meinesz solved this with a pendulum gravimeter built to be extremely sensitive to gravity while isolating or compensating for the ship’s motion, allowing reliable readings from aboard ships. He carried out extensive marine gravity surveys and produced gravity anomaly maps that highlighted differences between oceanic and continental crust. Those gravity anomalies reflect variations in crustal density and thickness, providing early evidence that helped convince scientists of continental drift and, later, plate tectonics. The other scientists listed were famous for work in other areas of physics and did not pioneer sea-based gravity measurement methods tied to continental drift.