Jan Oort, Astronomer
In 1950 Oort published an article in which it was shown that the
distribution of comet orbits, or, to be more exact, the distribution
of the inverse of the major axes of their orbits, can be explained
by assuming a reservoir of comets on the boundaries of the solar
system. Disturbances by passing stars will perturb comets out of their
roughly circular orbits within the reservoir, and some of them will
be led into orbits that take them close to the sun. Once they move through
the inner part of the Solar system, they may be trapped into thighter
orbits by Jupiter, and become periodic comets, like Halley’s comet.
25. Annotated copy of J.H. Oort’s article ‘The
structure of the cloud of comets surrounding the solar system, and a
hypothesis concerning its origin’ in Bulletin of the Astronomical Institutes
of the Netherlands vol. 11, No. 408 (January 13, 1950), pp. 91-110.
26. One of J.H. Oort’s exercise books (c. 1956),
entitled ‘Literature, Radio Astronomy’. Carefully organized reading notes,
arranged according to major subjects, indicated by Oort on the home-made
tabs, and preceded by a table of contents.
27. Original photographic plate which contains
the discovery detection of the Minor Planet (Asteroïd) Mieke, named after
Oort’s wife. Courtesy Dr. I. van Houten-Groeneveld.