Cornelis de Jager

Cornelis de Jager
Kees de Jager in 1967
Born	(1921-04-29) 29 April 1921 Den Burg, Texel, Netherlands
Residence	Den Burg
Fields	astrophysics, climate change
Institutions	Utrecht University
Alma mater	Utrecht University
Doctoral advisor	Marcel Minnaert
Spouse	Doetie Rienks

Cornelis "Kees" de Jager (born 29 April 1921) is a Dutch astronomer who specializes in predicting solar variation to assess the Sun's impact on future climate. He was the General Secretary of the IAU from 1967 to 1973 and former director of the observatory at Utrecht. He is a fellow with the Committee for Skeptical Inquiry.

Education

Born in Den Burg, de Jager spent his school years in the Dutch East Indies. From 1939 to 1945 he studied mathematics, physics and astronomy at Utrecht University. On 13 October 1952 he obtained his PhD with a thesis called "The Hydrogen Spectrum of the Sun". His supervisor was Marcel Minnaert.

Solar and stellar research

De Jager did work on stars and solar physics, in relation to which he was a founding editor of the journal Solar Physics.^[1] In 1980 he was principal investigator of the Hard X-ray Imaging Spectrometer (HXIS) on board the Solar Maximum Mission satellite.

From 1978 onward de Jager did noted work on the most luminous stars, known as hypergiants.^[2] From 1960 to 1986 de Jager was a professor at Utrecht University. In 1969 he became member of the Royal Netherlands Academy of Arts and Sciences.^[3]

Sun-climate relations

De Jager's current research focuses on predicting solar variation to assess the Sun's impact on future climate. Usually solar activity is defined in terms of the Sun's toroidal magnetic field, the field component parallel to the solar equator. Sunspots are one expression of this component. De Jager introduces the poloidal field of the Sun, which connects its two poles, as a factor of possibly similar importance. He uses proxies for both components and takes 19-year running averages to eliminate all effects that last only one or two solar cycles. Next he plots both components in a diagram, thus creating an experimental phase portrait. The track of the two components went from low to high activity around 1925. Around 2009 the same point has been passed in the opposite direction. Thus solar activity in the 21st century is expected to be lower than it was for most of the 20th century. A reduction in solar activity means less energy input to the Earth, thus counteracting global warming.

Cyclosophy

Expanding on a 1990 paper presentation at the International Skeptics Conference, de Jager published an article for Skeptical Inquirer Magazine where he parodies numerology. In Adventures in Science and Cyclosophy, de Jager claims that many times pseudoscientific reasoning ignores coincidences dealing with the relationship between objects when there are unlimited data points. He states that measurements surrounding the Great Pyramids have been used to show a relationship with astronomy. To do so, he explains, anyone can use the law of large numbers^[4] to relate to anything one would want, to try and prove there is some connection. As an illustration, he uses the example of his bicycle and the cosmos.^[5][6] Enthusiasts in this formula have created a website that allows visitors to submit data to replicate de Jager's experiment.^[7]

I measured the diameters of my bike's: -pedals, symbolizing the forward-going dynamics; -front wheel, which directs my ways into the unknown future; -lamp, enlightening my paths; -bell, though which I communicate with encounters. Thus I laid the building stones for a new holistic four-dimensional religion apt to the coming of the New Age of Aquarius: cyclosophy. The measurements were expressed in Holy Bike inches, being 17mm. This is so since 1 is the first prime number and 17 the seventh, and because seven is the holy number. Calling P, W, L and B the four measured quantities, it turns out that P ^ 2 √ L x W = 1823 which is the ratio between the masses of the proton and the electron.... Coincidences occur regularly in numerical experiments, as in daily life ... are not rare ... Most people greatly underestimate the enormous amount of possible combinations between numbers.Adventures in Science and Cyclosophy^[8]

According to Kendrick Frazier who attended the 1998 Second World Skeptics Congress in Heidelberg, Germany de Jager's "dead-pan" description of how he took measurements throughout the his house showing the "absurdities of those who attach great mystical significance to measurements of the Great Pyramid" had the audience "in stitches" Apparently "His home is in an astronomical observatory, a location, he said, 'that may be very close to the cosmos and well receptive to its incredible powers.'”^[9]

Other activities

Stichting Skepsis.

He was the General Secretary of the IAU from 1967 to 1973 and former director of the observatory at Utrecht.^[10] In 1981, de Jager became a founding member of the World Cultural Council.^[11] He was the first chairman of Stichting Skepsis from 1987 to 1998,^[12] the first chairman of the European Council of Skeptical Organisations from 1994 to 2001,^[13] and is also a Committee for Skeptical Inquiry fellow.^[14][15] de Jager joined his CSI peers by signing the "Deniers are not Skeptics" petition that asks the media to stop referring to climate change deniers as skeptics.^[16]

He spoke on astrology at the World Skeptics Congress in 1996.^[17]

Awards

• 1974 Karl Schwarzschild Medal^[18]
• 1984 Prix Jules Janssen
• 1988 George Ellery Hale Prize by the Solar Physics Division of the American Astronomical Society^[19]
• 1990 Committee for Skeptical Inquiry In Praise of Reason Award presented de Jager for his "notable contributions to science and his vigorous criticism of pseudoscience."^[20]

The asteroid 3798 de Jager is named for him.^[21]

Gallery

• 

  1986

• 

  2011

References

External links

• Cornelis de Jager homepage