Black holes are mysteries to astronomers. Nobody has ever actually seen a black hole, but scientists know they exist. A black hole is essentially a huge gravitational field so strong that it traps everything in its path, including light.
The image on the left, taken with a camera aboard the Hubble Space Telescope, shows the core of the galaxy M84 where scientists suspect that there is a black hole.
The colourful "zigzag" on the right is the signature of the same black hole in the center of galaxy M84, discovered by Hubble's Space Telescope Imaging Spectrograph (STIS).