Home Page Science Frontiers

No. 51: May-Jun 1987

Issue Contents

Other pages

Other Interesting Sites











A Larger Sun During The Maunder Minimum

Europe's so-called "Little Ice Age" (1645-1715) coincided with the Maunder Minimum -- a period during which sunspots were exceedingly rare. How was the sun different during the Maunder Minimum? This subject of solar variability (in both diameter and period of rotation) has been long debated. Some early measurements of solar diameter, begun at Greenwich in 1830, seemed to some to show a steadily shrinking sun, but others found cyclic patterns.

E. Ribes et al have just presented some data on solar diameter actually taken during the Maunder Minimum.

"By analysing a unique 53-year record of regular observations of the solar diameter and sunspot positions during the seventeenth century, we have shown for the first time that the angular diameter was larger and rotation slower during the Maunder Minimum."

A larger sun might be cooler, providing less heat, thus accounting for climate changes. (Ribes, E., et al; "Evidence for a Larger Sun with a Slower Rotation during the Seventeenth Century," Nature, 326: 52, 1987.)

Comment. Just why the sun expands and contracts over a period measured in hundreds of years is a major astro physical conundrum.

Variation in solar diameter Variation in solar diameter, 1860-1940. Arrows indicate sunspot maxima. (From ASO-X6 in The Sun and Solar System Debris).

From Science Frontiers #51, MAY-JUN 1987. 1987-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987