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John A. Eddy

John A. Eddy

American astronomer
John A. Eddy
The basics

Quick Facts

Intro American astronomer
Was Astronomer
From United States of America
Type Science
Gender male
Birth 25 March 1931, Pawnee City, Pawnee County, Nebraska, USA
Death 10 June 2009, Tucson, Pima County, Arizona, USA (aged 78 years)
Star sign Aries
United States Naval Academy
University of Colorado
Peoplepill ID john-a-eddy
The details (from wikipedia)


John Allen "Jack" Eddy (March 25, 1931 – June 10, 2009) was an American astronomer who published professionally under the name John A. Eddy but much of the content referencing him can be found under his nickname Jack which he preferred to use. In 1976 Dr. Eddy published a landmark paper in Science titled "The Maunder Minimum" where, using the Nineteenth Century works of Edward W. Maunder and Gustav Spörer, he identified a 70-year period from 1645 to 1715 as a time when solar activity all but stopped. In making the case for the anomaly, he gathered and interpreted data from a wide variety of sources, including first-hand accounts from extant historical observations of the Sun going back to the telescopic observations of Galileo and other contemporary scientists of the 17th and early 18th centuries; from historical reports of the aurora borealis observed in past centuries in Europe and the New World; from visual observations of sunspots seen with the unaided eye at sunrise and sunset in dynastic records from the Orient; from existing descriptions of the eclipsed Sun; and from measurements of carbon-14 in dated tree-rings. In the last of these, which can be used as a proxy indicator of solar activity, he found evidence of other similar periods of solar quiescence in the distant past, the most recent an even longer 90-year span, from about 1460 until 1550, which he named the Spörer Minimum. Both the Maunder and Spörer minima fell during the coldest parts of the Little Ice Age, which suggested a meaningful connection between the longer term behavior of the Sun and of the Earth's mean surface temperature. In advancing the theory that the Sun is a variable star Eddy observed: "It has long been thought that the Sun is a constant star of regular and repeatable behavior. Measurements of the radiative output, or solar constant, seem to justify the first assumption, and the record of periodicity in sunspot numbers is taken as evidence of the second. Both records, however, sample only the most recent history of the Sun."

Childhood and education

Midshipman John Allen Eddy, U.S. Naval Academy Class of 1953.

John Eddy was born (March 25, 1931) and raised in Pawnee City, Nebraska, a small town of 1600 people in the southeastern corner of the state. John's brother Robert was two years his senior and his sister Lucille was two years his younger. John's father managed a cooperative farm store where John worked until he started high school. John's mother had attained college for one year and was a county schoolteacher until she married John's father. The Eddy family lived in a modest but happy home but were of limited economic means and there was serious concerns that they could not afford a college education for John. As it turned out, John was the only member of the family to graduate from college. In 1948 John attended Doane College in Crete, Nebraska for one year, a distance of some 80 miles (130 km) from his home. In 1949 he was appointed by Senator Kenneth Wherry (R) of Nebraska, who also resided in Pawnee City, to the U.S. Naval Academy. At Annapolis, there were few science courses but John attended a course in celestial navigation and it was this course which gave John a love of the sky. So great was his interest in the night sky that once after Taps, John crawled out on the roof of Bancroft Hall to look for the Constellation Draco and was caught by an officer who gave him 5 hours of extra duty for not being in bed.

Upon graduation in 1953 from the United States Naval Academy he served for four years at sea as a line officer on aircraft carriers during the Korean War and later in the Persian Gulf as navigator and operations officer on a destroyer in the Atlantic Fleet. In 1957 he left active service in the Navy to continue his education. He was discharged and accepted into the graduate school at the University of Colorado's mathematics program but switched departments, before the start of the Fall 1957 semester, upon discovering the University's little observatory and a small program in astro-geophysics that had just been started, becoming the program's first student. Later he joined the High Altitude Observatory at the University of Colorado.

Academic career

As a protege of Gordon Newkirk, Eddy worked with Princeton Professor Martin Schwarzschild in studying the solar corona with coronagraphs mounted on weather balloons at altitudes of 80,000 feet (24,000 m). Eddy's thesis was in this area of study.

Eddy completed his PhD Thesis at the University of Colorado at Boulder in December 1961 titled "The Stratospheric Solar Aureole".

Abstract: The theory of light scattering by small particles is summarized to develop the formulae needed to interpret solar aureole data obtained in balloon flights at stratospheric altitudes. Included are the Rayleihg law for small particles, the Chandrasekhar solution of the planetary scattering problem, and the Mie theory for large particle scattering. Observations cover the wavelength range from 0.37 to 0.79 micrometre at the scattering angle 2.4 degrees, and over the altitude range from 42,000 ft. to 80,000 ft. The findings suggest that the form of the particle size distribution changes with altitude, becoming a steeper function of particle radius at higher altitudes.

After achieving his PhD, Eddy went into teaching, while maintaining an active research schedule to maintain his credentials. He studied spectral lines and particularly doing work in infrared spectroscopy.

Interdisciplinary work

Eddy received much criticism from within the astronomy community for his interdisciplinary work on Native American medicine wheels, showing how they were used as calendars and observatories. It also earned him criticism from archaeologists at first, although his work was eventually accepted, and even documented in National Geographic and as a guest on TV and radio programs.

As a teacher, he frequently used historical examples to put his students at ease with the idea that not so long ago nobody knew more than they did about solar physics. This caused him to do a lot of research in the history of his own field, particularly covering records of past eclipses and sunspot counts, whereupon he discovered the records of Maunder and others demonstrating that there was indeed long term variability in solar activity.

Eugene Parker of the University of Chicago, when promoting his theory of the existence of a solar wind, which caused Parker to receive much scorn from the community, exposed Eddy to the work of Maunder vis a vis sunspot records.


Eddy was laid off from the High Altitude Observatory at the National Center for Atmospheric Research (NCAR) in 1973 due to budget cutbacks and the poor performance reviews he earned due to his interdisciplinary forays, which were frowned upon at the time. He then was hired by NASA to write a book, which enabled him to travel east to do research in the great astronomy libraries, particularly at Harvard and the Naval Observatory, which he used to also do research on the Maunder Minimum. His work on this was published in the journal Science as a cover story, and established his fame. After publication, his former employers at the HAO tried to hire him back.

The fame resulting from "The Maunder Minimum" paper landed him on the international lecture circuit, giving over 50 talks a year around the world about his work and history.

In 1987 Eddy was awarded the Arctowski Medal by the National Academy of Sciences for studies in solar physics and solar-terrestrial relationships and specifically for "his demonstration of the existence and nature of solar variations of long term and the consequences of these changes for climate and for mankind."

Petition to name the next significant solar minimum

There was an online petition underway, organized by Anthony Watts, to be submitted to the Solar Physics Division of the American Astronomical Society in June 2009, in Boulder, Colorado by solar astronomer Leif Svalgaard, to name the next significant solar minimum the "Eddy Minimum" to honor Eddy's contributions to this line of research.

During an interview, in a statement which may yet prove prophetic, Eddy first used the term "Eddy Minimum" while explaining why he rejected it:

EDDY: And, you know, the temptation was to think that it might someday be called the "Eddy Minimum": that is, to call it nothing in the hope that someone else would do that. But being from Nebraska, I could never do anything like that. I also knew I wasn't the first to find it, and it wasn't really mine. I think I did quite a bit for Maunder with that name. Particularly because he also got the idea from somebody else. He got it from Sporer who was a German astronomer. So, among the shots I took after publishing the paper were some from Germany that said, "You know, you really named it after the wrong person." Which I knew very well.

While Eddy did not predict the next significant solar minimum he did identify that we are living by the light of a variable star and it is for this reason it is said that the next significant solar minimum should be named in his honor. He cautioned:

It was one more defeat in our long and losing battle to keep the Sun perfect, or, if not perfect, constant, and if inconstant, regular. Why we think the Sun should be any of these when other stars are not is more a question for social than for physical science.


John A. Eddy died of cancer at his home in Tucson, Arizona on June 10, 2009.



  • Fellow, American Association for the Advancement of Science, 1988.
  • Arctowski Medal in Solar and Solar-Terrestrial Physics, National Academy of Sciences, 1987
  • Visiting Scientist, University of Durham, England, 1985, 1987.
  • James Arthur Prize Lecture in Solar and Solar Terrestrial Physics, Harvard-Smithsonian Center for Astrophysics, 1983.
  • Research Fellow, National Geographic Society, 1975-1976.
  • NCAR Award for Outstanding Performance in New Technology, 1973.
  • Sigma Xi-RESA Boulder Scientist Award, 1965.
  • National Academy of Sciences/National Research Council Post-Doctoral Fellow, 1962-1963.



  • The New Solar Physics (Editor) Westview Press. 1978, 214 pp, ISBN 0-89158-444-7.
  • A New Sun (The Solar Results from Skylab) NASA SP-402, U.S. Government Printing Office, 1979. 198 pp.
  • The Ancient Sun (Co-Editor, with R.O. Pepin and R.B. Merrill) Pergamon Press, 1980, 581 pp, ISBN 0-08-026324-0.
  • Mapping the Sky (Co-Editor, with S. DeBarbat, H.K. Eichhom and A.R. Upgren) Kluwer Academic Publishers, 1988, 512 pp, ISBN 90-277-2809-7.
  • Global Changes in the Perspective of the Past (Co-Editor, with H. Oeschger) John Wiley & Sons, Chichester, 1993, 383 pp., ISBN 0-471-93603-0.
  • The Sun, the Earth and Near-Earth Space: A Guide to the Sun-Earth System; NASA NP-2009-1-066-GSFC, U.S., 2009, 311 pp, ISBN 0160838088.



  • John A. Eddy, Solar Detective, Dies at 78; NY Times Science
  • Obituary: John A. Eddy; Boulder Daily Camera
  • Jack Eddy; Daily Telegraph Science Obituaries
  • Obituary: John A. Eddy '53; U.S. Naval Academy, Alumni Association
The contents of this page are sourced from Wikipedia article on 23 Apr 2021. The contents are available under the CC BY-SA 4.0 license.
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