Team tracks 12 clocks for 14 years to test Einstein's theory
Physicists at US' National Institute of Standards and Technology constantly monitored 12 high-precision atomic clocks spread around the world from 1999 to 2014. The experiment tested Einstein's thought experiment involving Earth as a free-falling elevator in Sun's gravity, where all objects would accelerate at the same rate. The clocks remained synchronised for over 14 years, proving the theory.