Lasers fired east and west arrive at different times due to Earth's rotation
the verdict
SUPPORTED
the evidence backs this
confidence 82/100
Laser beams and optical interferometers travelling in opposite directions experience time and phase differences due to the rotation of the Earth, a phenomenon known as the Sagnac effect which is routinely measured by ring laser gyroscopes.
Evidence for · 5
Accurate measurement of the Sagnac effect for matter waves.
2022 · cited by 11
Paper [2] uses matter wave interferometry to measure the phase shift induced by Earth's rotation.
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More for · 4
Sagnac Effect Compensations and Locked States in a Ring Laser Gyroscope
2023 · cited by 10
Paper [3] discusses ring laser gyroscopes and compensating for the Sagnac effect caused by rotation.
Noise Analysis of a Passive Resonant Laser Gyroscope.
2020 · cited by 5
Paper [8] explains how large-scale laser gyroscopes measure the Earth's rotation without external references via the Sagnac effect.
Gyroscope measurements of the precession and nutation of Earth's axis.
2025 · cited by 3
Paper [9] demonstrates the operation of a free space ring laser gyroscope measuring rotation relative to inertial space, detecting Earth's dynamics.
Rotation Active Sensors Based on Ultrafast Fibre Lasers.
2021 · cited by 2
Paper [10] reviews ultrafast fibre lasers employing the optical Sagnac effect to accurately measure angular velocity and Earth rotation.