Gravitational Waves distort (stretch and squeeze) the very fabric of space-time, warping the distances between any celestial objects making the ability to travel vast distances in litte time

"Gravitational waves are created by any object that spins, such as the rotating remnants of stellar corpses, orbiting black holes or even two people “doing a do-si-do,” Dr. Mingarelli said. But unlike other types of waves, these ripples stretch and squeeze the very fabric of space-time, warping the distances between any celestial objects they pass by.

“It sounds very sci-fi,” Dr. Mingarelli said. “But it’s for real.”"
https://www.nytimes.com/2023/06/28/science/astronomy-gravitational-waves-nanograv.html