Jan H Oort Biography

In the year 1900, on April 28th, Jan H Oort was born in Franker, Friesland, the Dutch province. He later grew up to study in the city of Groningen alongside Jacobus Kapteyn, with a Ph D thesis titles "Stars with High Velocity".

In 1924, Oort discovered the galactic halo, the clusters of stars outside the disk of the Milky Way. By 1927, Oort provided evidence of Bertil Linndblad's theory of the Milk Way's rotation through close observation of the stars; as well as calculating the centre of the Milky Way being at 5 900 parsecs in the direction of Sagittarius.

1932 marked the first proof of dark matter, provided by Oort. He resolved that the mass of the universe cannot be made up of all mass we can see; there must be more than that. The mass of the Milky Way is 100 billion times that of the sun, and not all of that is evidently visible in the disk. His studies of star motion further proved his point.

In the solar system, there is a home to comets that was hypothesised by Oort, and has been dubbed the Oort Cloud following its discovery. The spherical cloud is primarily composed of ices--water, ammonia, and methane. It lies roughly a light-year from the sun.

He discovered polarised light from the Crab Nebula, seen through a synchrotron spectrum.

Among his awards and honours are the Bruce Medal, The Gold Medal of the Royal Astronomical Society, the Karl Schwarzchild Medal, and the Balzan Prize.

When Oort passed on November 5th, 1992, the renowned astrophysist Subrahmanyan Chandreskhar said "The great oak of Astronomy has felled, and we are lost without its shadow."