It was the subject of a Scientific American special report dealing with Modified Newtonian Dynamics 
It was the subject of a Scientific American special report dealing with Modified Newtonian Dynamics by Mordechai Milgrom ("MOR-de-kye MILL-grum"). This substance was first proposed in 1934 by Fritz Zwicky ("ZWICK-ee") to make up for "missing mass" in the universe. Its non-baryonic ("NON BARE- ee-on-ick") variety contains no mass. For 10 points, identify this type of matter in the universe named due to its unobservability.
It was the subject of a Scientific American special report dealing with Modified Newtonian Dynamics by Mordechai Milgrom ("MOR-de-kye MILL-grum").
{dark matter} [accept {dark} matter after “{matter}” is read]