Gravitational Wave Polarization: Ring of Test Masses

This simulator visualises the one effect that actually defines a gravitational wave: a ring of free-falling test particles, sitting in the plane perpendicular to the wave's direction of travel, gets rhythmically stretched along one axis while it is squeezed along the perpendicular axis — then the pattern flips on the next half-cycle. That alternating quadrupole distortion, not a simple push or pull, is exactly what LIGO's kilometre-scale mirrors measure as a passing wave changes the interferometer's arm lengths by a fraction of a proton's width. Dial in the strain amplitude and frequency, and slide between the plus (+) and cross (×) polarization states — the two independent ways spacetime itself can ripple — while live readouts track the instantaneous strain h(t) and the wave's phase.