Final answer:
Scientists discover new black holes by observing their effects on surrounding space rather than directly viewing them.
Step-by-step explanation:
In order to discover new black holes, scientists observe the effects they have on space around them, rather than directly viewing the black holes themselves.
One way scientists detect black holes is by observing the gravitational effects they have on nearby objects. For example, if a star appears to be moving in a strange pattern or orbiting an invisible object, it could be an indication of a black hole's presence.
Another method is to look for the emission of X-rays from hot gas falling into the black hole, which can be detected using X-ray telescopes.
Learn more about Discovering black holes