Dark Matter distorts light
From NASA.gov, an image depicting how Dark Matter (in red) distorts light from distant galaxies as it travels across the universe.
Explanation: Is the distant universe really what it appears to be? Astronomers hope not. Intervening dark matter, which is normally invisible, might show its presence by distorting images originating in the distance universe, much the way an old window distorts images originating on the other side.