The reason we typically can't see other stars or solar systems around a black hole is primarily due to two factors: the extreme gravitational pull of the black hole and the intense radiation emitted by the accretion disk.
Gravitational Pull: Black holes have an incredibly strong gravitational pull. They create a region around them called the event horizon, which is the point of no return. Anything that crosses the event horizon, including light, cannot escape and is trapped within the black hole. As a result, the gravitational pull of the black hole bends the paths of light rays coming from other stars or solar systems, causing them to be deflected or "gravitationally lensed." This effect makes it challenging to observe distant objects behind or near a black hole.
Accretion Disk: Many black holes have an accretion disk—a swirling disk of superheated gas and dust that forms as matter falls toward the black hole. The accretion disk emits intense radiation, including X-rays and gamma rays, as the material is compressed and heated to extremely high temperatures. This radiation can outshine the light from other stars or solar systems, making it difficult to observe them directly.
Furthermore, the gravitational pull of the black hole can distort and warp the spacetime around it, which can further affect the paths of light rays and make it challenging to see objects behind the black hole.
However, it's important to note that astronomers can indirectly infer the presence of other stars or solar systems around a black hole through various observational techniques. These techniques include studying the effects of the black hole's gravity on nearby objects or detecting changes in the accretion disk caused by the presence of other celestial bodies. While we may not directly see these objects, their influence can be detected and studied through these methods.