Sedna at 126 AU appears to be the most distant object discovered in the solar system. Beyond that is the hypothetical Oort Cloud. How far beyond that does the suns gravity control and are there theories about what might be out there beside emptiness?
Gravitational force doesn’t have a distance limit. It gets weaker the further you go, and at some point it’ll become undetectable, but it won’t be comletely zero.
The heliopause is the most commonly used definition for the “edge of the solar system.” That’s where the solar wind hits and mixes with the interstellar medium. The Voyager spacecraft are almost there.
The Oort Cloud extends to about 3 light years from the sun and that distance is consodered pretty much the end of the sun’s influence (I suppose technically our sun contrubutes to the galaxy’s overall mass which affects other galaxies but its influence is pretty diluted). Since the Oort Cloud does end at 3 LY I think it is evidence our sun doesn’t have any more “reach” else something would likely manage to float even further out.
After that interstellar space is pretty much empty with the odd atom here and there (I forget the density but a vague memory has it at like 1 atom/m[sup]3[/sup]…could well be wrong on that).