Yes, gravitational waves can travel across the galaxy. Gravitational waves are ripples in the fabric of spacetime caused by the acceleration of massive objects. They were first predicted by Albert Einstein's theory of general relativity and were directly detected for the first time in 2015.
Gravitational waves can be generated by a variety of astrophysical events, such as the merger of two black holes, the collision of neutron stars, or even the early moments of the Big Bang. When these events occur, they can create gravitational waves that propagate outward from their source at the speed of light.
Since gravitational waves are a fundamental property of spacetime, they are not impeded by the vast distances between galaxies. They can travel through space, unaffected by intervening matter or electromagnetic fields. This means that gravitational waves emitted by events within our own galaxy can propagate across the Milky Way and potentially be detected by sensitive instruments on Earth or in space.
However, it's important to note that gravitational waves do weaken as they travel through space. The amplitude of a gravitational wave decreases with distance, so by the time a gravitational wave reaches us from a distant galaxy, it may be extremely faint and challenging to detect. Nonetheless, gravitational wave astronomy has opened up a new window to observe the universe and study phenomena that were previously inaccessible through traditional telescopes.