The existence of rogue planets or rogue solar systems, also known as interstellar or intergalactic objects, is theoretically possible. These are planetary systems or individual planets that are not gravitationally bound to any specific star and instead drift through interstellar or intergalactic space.
The formation of such objects can occur through various mechanisms. One possibility is that they are ejected from their original stellar systems due to gravitational interactions with other celestial bodies or even during the chaotic early stages of a star cluster's formation. Another possibility is that they form directly from the gravitational collapse of interstellar gas and dust without ever being part of a stellar system.
While rogue planets have been detected within our own galaxy, such as through microlensing observations, it is challenging to determine the precise number or distribution of intergalactic objects due to the limitations of current observational techniques. Moreover, intergalactic space is vast and sparsely populated, making it even more difficult to detect these objects.
While there is currently no direct observational evidence of rogue planets or solar systems existing outside of our galaxy, it remains a possibility given the vastness of the universe and the potential for planetary systems to be untethered from their parent stars. Further advancements in observational technology and future discoveries may provide more insights into the prevalence and characteristics of such objects.