John A. Eddy

John Allen "Jack" Eddy (March 25, 1931 – June 10, 2009) was an American astronomer. He studied historical sunspot records, and popularised the name '' Maunder Minimum'' for the sunspot minimum which occurred in the late 17th century.

Childhood and education

John Eddy was born and raised in Pawnee City, Nebraska. His brother Robert was two years his senior and his sister Lucille was two years his younger. His 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 his father. The Eddy family were of limited economic means and were concerned that they could not afford a college education for John. As it turned out, he was the only member of the family to graduate from college. In 1948, he attended Doane College in Crete, Nebraska for one year, a distance of some from his home. In 1949 he was appointed by Senator Kenneth Wherry of Nebraska, who also resided in Pawnee City, to the U.S. Naval Academy. At Annapolis, there were few science courses but Eddy attended a course in celestial navigation, which gave him a love of the sky. So great was his interest in the night sky that once after Taps, he crawled out on the roof of Bancroft Hall to look for the Constellation Draco and was caught by an officer who gave him five hours of extra duty for not being in bed.

Upon graduation in 1953 from the United States Naval Academy, Eddy 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 observatory and a 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.Interview with Jack Eddy, April 21, 1999: In Michigan by phone, conducted by Spencer Weart
/ref>Obituary: John A. Eddy, Boulder Daily Camera, June 14, 2009
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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 . Eddy completed his PhD Thesis at the University of Colorado at Boulder in December 1961 titled "The Stratospheric Solar Aureole". After obtaining his PhD, Eddy went into teaching, while maintaining an active research schedule to maintain his credentials. He studied spectral lines and worked on infrared spectroscopy.

Interdisciplinary work

Eddy received much criticism from within the astronomy community for his interdisciplinary work on Native American medicine wheels, which showed how they were used as calendars and observatories.Eddy, J.A., "Astronomical Alignment of the Big Horn Medicine Wheel", Science 184, pp. 1035-1043, 1974
/ref> It also earned him criticism from archaeologists at first, although his work was eventually accepted, and later documented in National Geographic and as a guest on TV and radio programs.

As a teacher, he frequently used historical examples to show his students that not so long ago nobody knew more than they did about solar physics. This led 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 Edward 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, exposed Eddy to Maunder's work on sunspot records.

Solar minimum paper

In 1976 Eddy published a 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 in which solar activity was extremely low. 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