## Scientists opened a sealed envelope after 10 years. Gravity still didn’t make sense For 10 years, physicist Stephan Schlamminger had been chasing one of the most stubborn numbers in science. Now, after a decade of experiments, corrections, and painstaking analysis, the answer was sitting inside a sealed envelope. He was not entirely sure he wanted to open it. Schlamminger, a physicist at the National Institute of Standards and Technology (NIST), had spent much of the previous decade trying to measure the universal gravitational constant. Known to physicists as big G, this fundamental…