Jacobus Kapteyn | |
|---|---|
 Jacobus Kapteyn. Painting by Jan Veth (1921). | |
| Born | Jacobus Cornelius Kapteyn 19 January 1851 |
| Died | 18 June 1922 (aged 71) |
| Nationality | Dutch |
| Alma mater | University of Utrecht |
| Known for | discovery of evidence for galactic rotation |
| Awards | Bruce Medal 1913 |
| Scientific career | |
| Fields | Astronomy |
Jacobus Cornelius Kapteyn (19 January 1851 – 18 June 1922) was a Dutch astronomer. He carried out extensive studies of the Milky Way. He found that the apparent movement of stars was not randomly distributed but had two preferential directions: the two star streams. This discovery was later reinterpreted as evidence for galactic rotation. Kapteyn also suggested that these stellar velocities could be used to find the amount of non-luminous matter in the galaxy.[1]
- ^ Kapteyn, Jacobus Cornelius (1922). "First attempt at a theory of the arrangement and motion of the sidereal system". Astrophysical Journal. 55: 302–327. Bibcode:1922ApJ....55..302K. doi:10.1086/142670. In concurrence with his contemporaries, he used to the term "dark matter" to designate this non-lumininous matter, which was thought to be dust and gas. "It is incidentally suggested that when the theory is perfected it may be possible to determine the amount of dark matter from its gravitational effect.