You are talking to a friend who tells you she just saw a black hole in space. How would you respond?
Tell your friend to verify her sighting through a compound telescope.
Tell your friend that black holes are too far away for us to view them without a
sextant, so it is unlikely she saw a black hole.
Tell your friend that black holes can only be detected from their quasars, and ask
her if she saw a quasar, or a glowing ring around a black spot in space.
Tell your friend that this is unlikely as black holes are invisible to the naked eye
because their light cannot travel back to us in order for us to view them.