What is the main challenge astronomers face when trying to directly detect black holes? (1 point)

The main challenge astronomers face when trying to directly detect black holes is that black holes do not emit any light or radiation that can be directly observed. They are essentially invisible. Astronomers typically observe the effects of black holes, such as their gravitational pull on surrounding objects or the X-rays emitted by hot gases spiraling into them, rather than directly detecting the black holes themselves.