Jan Hendrik Oort (April 28, 1900 – November 5, 1992) was an internationally famous Dutch astronomer. He profoundly stimulated radio astronomy. The well-known Oort cloud bears his name. April 28 is the 118th day of the year (119th in leap years) in the Gregorian Calendar, with 247 days remaining. ... 1900 is a common year starting on Monday. ... November 5 is the 309th day of the year (310th in leap years) in the Gregorian Calendar, with 56 days remaining. ... 1992 is a leap year starting on Wednesday of the Gregorian calendar. ... Microwave image of 3C353 galaxy at 8. ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ...

Oort was born in Franeker in Friesland and studied in Groningen with Jacobus Cornelius Kapteyn. His Ph.D thesis was titled The stars of high velocity. In 1927 he proved that the Milky Way galaxy rotates, by analyzing the movements of stars. In 1935 he became professor at Leiden University at the faculty where Ejnar Hertzsprung was the director. Franekeradeel is a municipality in the northern Netherlands. ... For information on the region extending from the Netherlands to Denmark, see Frisia. ... Groningen is a municipality and city in the north of the Netherlands, and capital of Groningen province. ... Jacobus Cornelius Kapteyn, (January 19, 1851 – June 18, 1922) was a Dutch astronomer, best known for his extensive studies of the Milky Way and as the first discoverer of evidence for galactic rotation. ... 1927 was a common year starting on Saturday (link will take you to calendar). ... The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Galaxia Kuklos) is the galaxy in which the Earth is found. ... The Pleiades star cluster A star is any massive gaseous body in outer space. ... 1935 was a common year starting on Tuesday (link will take you to calendar). ... Leiden University in the city of Leiden, is the oldest university in the Netherlands. ... Ejnar Hertzsprung (October 8, 1873, Copenhagen – October 21, 1967, Roskilde) was a Danish chemist and astronomer. ...

Oort was fascinated by radio waves from the universe. After the Second World War he was a pioneer in the new field of radio astronomy, using an old radar antenna from the Germans. The deepest visible-light image of the cosmos. ... Mushroom cloud from the nuclear explosion over Nagasaki rising 18 km into the air. ... Microwave image of 3C353 galaxy at 8. ...

In the 1950s he raised funds for a new radio telescope in Dwingeloo, in the east part of the Netherlands, to research the centre of the galaxy. In 1970 a bigger telescope (the Westerbork Synthesis Radio Telescope) was built in Westerbork, near the old one. It consisted of twelve smaller telescopes working together as an interferometer to perform aperture synthesis observations, a technique which had been previously suggested by Oort, but which was first tested experimentally in Cambridge by Martin Ryle and in Sydney by Joseph Pawsey. The Parkes 64 metre radio telescope in New South Wales, Australia (the bigger of the two shown) In contrast to an ordinary telescope, which produces visible light images, a radio telescope sees radio waves emitted by radio sources, typically by means of a large parabolic (dish) antenna, or arrays of... Westerveld is a municipality in the northeastern Netherlands. ... 1970 was a common year starting on Thursday. ... The Westerbork Synthesis Radio Telescope (WSRT) (near Westerbork (camp), north of Westerbork (village), m. ... Midden-Drenthe is a municipality in the northeastern Netherlands. ... Interferometry is the applied science of combining two or more input points of a particular data type, such as optical measurements, to form a greater picture based on the combination of the two sources. ... Aperture synthesis is a type of interferometry that mixes signals from a collection instruments to produce measurements having the same angular resolution as an instrument the size of the entire collection. ... The University of Cambridge is the second-oldest university in the English-speaking world, with one of the most selective entry requirements in the United Kingdom. ... Sir Martin Ryle (September 27, 1918 – October 14, 1984) was a British radio astronomer who developed revolutionary radio telescope systems (see e. ... The University of Sydney The University of Sydney, established in 1850, is the oldest university in Australia, and it is located in Sydney, the capital city of the state of New South Wales. ...

His hypothesis that the comets have a common origin, postulated in 1950, was later proven to be correct. Another contribution of Oort was that he was able to demonstrate that the light from the Crab nebula was polarized. Comet Hale-Bopp, showing a white dust tail and blue gas tail (February 1997) A comet is a small body in the solar system that orbits the sun and (at least occasionally) exhibits a coma (or atmosphere) and/or a tail -- both due primarily to the effects of solar radiation... 1950 was a common year starting on Sunday (link will take you to calendar). ... Messier Object 1, the Crab Nebula. ... This article treats polarization in electrodynamics. ...

A few of Oort's Discoveries

• Oort calculated that the centre of the Milky Way was 30,000 light years from the Earth in the direction of the constellation Sagitarius.

• He showed that the Milky Way had a mass 100 billion times that of the Sun.

• In 1950 he suggested that comets came from a common region of the Solar System (now called the Oort cloud).

• He found that the light from the Crab nebula was polarised, and produced by synchrotron emission.

The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Galaxia Kuklos) is the galaxy in which the Earth is found. ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... Synchrotron radiation is electromagnetic radiation, similar to cyclotron radiation, but generated by the acceleration of relativistic electrons (i. ...

Honors

Awards

• Bruce Medal in 1942
• Gold Medal of the Royal Astronomical Society in 1946
• Henry Norris Russell Lectureship in 1951

Named after him The Catherine Wolfe Bruce gold medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. ... This article is about the year. ... The Gold Medal is the highest award of the Royal Astronomical Society. ... 1946 was a common year starting on Tuesday. ... The Henry Norris Russell Lectureship is awarded each year by the American Astronomical Society in recognition of a lifetime of excellence in astronomical research. ... 1951 was a common year starting on Monday; see its calendar. ...

• Asteroid 1691 Oort
• Oort Cloud
• Oort constants of galactic structure