Gravitational waves stretch and shrink the fabric of spacetime itself. But they also have a lesser-known (and lesser-understood) property. After their passage, they leave a permanent mark on the Universe, forever changing the distances between two points in space. This effect, called gravitational memory, is predicted in general relativity to be very small, but it could potentially be isolated in future gravitational-wave detectors, such as the spaceborne Laser Interferometer Space Antenna (LISA). A new theoretical study by Boris Goncharov from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Germany and colleagues explores what we might learn about spacetime symmetries of the Universe from the detection of gravitational memory [1]. The results suggest that memory observations may offer insights into how general relativity can be unified with quantum theory.
To read more, click here.