Gravitational waves propagate in an omnidirectional manner, meaning they spread out in a spherical configuration from their source. They do not propagate as plane waves in one dimension.
Gravitational waves are ripples in the fabric of spacetime caused by the acceleration of massive objects. When a gravitational wave is generated, it radiates outward in all directions, similar to the way ripples spread on the surface of a pond when a stone is thrown into it. As these waves propagate through space, they cause stretching and squeezing of spacetime, affecting objects in their path.
The propagation of gravitational waves as spherical waves is a consequence of the nature of spacetime itself. According to Einstein's theory of general relativity, gravitational waves are disturbances that travel at the speed of light and carry energy away from their source. They spread out in a radial pattern, expanding and contracting spacetime as they move through it.
When a gravitational wave reaches a distant observer, it appears as a passing deformation of space and time. The observer will experience the stretching and squeezing of space as the wave passes through their location. This effect is typically detected using highly sensitive instruments, such as interferometers, which can measure tiny changes in the distances between objects caused by the gravitational wave passing through.
So, in summary, gravitational waves propagate in an omnidirectional manner, spreading out in a spherical configuration from their source, rather than as plane waves in one dimension.