Basic timeline of dark matter

This post is a basic timeline of dark matter. There are 6 events listed below chronologically. Source: Wikipedia

• 1884: William Thomson proposes dark bodies in the Milky Way Galaxy
• 1906: Henri Poincaré uses the term 'matière obscure' ('dark matter') to describe Thomson's observations
• 1922: Jacobus Kapteyn proposes dark matter based on stellar velocities
• 1933: Fritz Zwicky proposes 'dunkle materie' ('dark matter') by applying the the virial theorem to a galaxy cluster
• 1939: Horace W. Babcock reports unexpectedly fast outer stars in the Andromeda Galaxy
• 1960s-1970s: Vera Rubin, Kent Ford and Ken Freeman use a spectrograph to measure unexpectedly fast outer stars in spiral galaxies