“…In the case of gravity, work is underway to identify and measure signals for spacetime-symmetry breaking in the weak-field gravity regime. Analysis has already been performed with lunar laser ranging [6,7], atom interferometric gravimetry [8,9], gyroscopic tests [10], binary-pulsar tests [11], shortrange gravity tests [12][13][14] planetary ephemeris [15], cosmic rays [16], gravitational waves [17,18], and others [19].…”