If an object falls into a black hole, its fate depends on several factors, such as the size and mass of the black hole and the properties of the object itself.
As an object approaches the event horizon of a black hole (the point of no return), the gravitational pull becomes increasingly stronger. If the object crosses the event horizon, it is effectively trapped within the black hole's gravitational well and cannot escape. At this point, its ultimate destiny is uncertain, as our current understanding of physics breaks down at the singularity within a black hole.
According to general relativity, the singularity is a point of infinite density and curvature, where the laws of physics as we know them cease to be applicable. At the singularity, the object is thought to be crushed to a point of zero volume, known as a gravitational singularity. However, since our current theories cannot fully describe the physics at the singularity, the exact nature of what happens is still a topic of active research and remains a subject of debate among physicists.
Regarding an object passing by a black hole at the speed of light, it's important to note that nothing with mass can attain or exceed the speed of light according to our current understanding of physics. As an object with mass approaches the event horizon of a black hole, its velocity relative to an outside observer will asymptotically approach the speed of light, but it will never actually reach or surpass it.
However, if we consider a hypothetical scenario where an object could travel at the speed of light, passing by a black hole, its trajectory would still be affected by the black hole's gravity. The intense gravitational field of the black hole would cause spacetime to be significantly curved, which would bend the path of the object. The object would be deflected from its original trajectory but would continue moving at the speed of light, following a curved path around the black hole.
It's important to emphasize that these descriptions are based on our current understanding of physics, specifically general relativity, and that the behavior of objects near black holes is an area of active scientific research.