“Atomic clocks have also been used to detect and measure time dilation, the effect of velocity or gravity on time. Relative velocity slows time. Greater gravity also slows time; for example, at higher altitudes on Earth time actually moves a wee bit faster.
Because of this difference, atomic clocks can be placed at different altitudes to measure gravity itself. This means these new clocks could – theoretically – be used to measure the shape of Earth’s gravitational field, a field known as relativistic geodesy, to within an accuracy of a centimeter.
But atomic clocks this precise, and so sensitive to gravity, could also potentially detect the incredibly faint signals from gravitational waves. –Science Alert”