measuring the intervals, astronomers can discern the orbits and gauge the two bodies' gravitational effects with great accuracy.
Relativity predicts that gravitational waves thrown off as the two stars whirl in space should reduce the total amount of energy in the system. The authors reasoned that this loss would slow PSR 1913+ 16's orbital speed and gradually shrink both the size of its orbit and the time it takes to circle its companion. Indeed, after six years, the deviation was more than one...