Why NIST Researchers Spent 10 Years Measuring Gravity

Physicists have been trying to measure the fundamental gravitation al constant for well over two centuries. The current accepted value of big G , as it’s known, is 6.67430 × 10 -11 cubic meters per kilogram per square second. It also has an uncertainty of ±0.00015 × 10 -11 m 3 /(kg s 2 ).