The Maunder Minimum Revisited

Sunset near Albany, Western Australia Photo: John Maunder

Sunspot numbers since 1700.

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The "Maunder Minimum" is the name given to the period from 1650 to 1700 when

the number of sunspots became almost zero. The period is named after the

solar astronomer Edward Walter Maunder (1851-1928) who while working at The Royal

Observatory, Greenwich discovered the dearth of sunspots during the 1650-1700 period.

During one 30 year period within the Maunder Minimum there were only about 50 sunspots

compared with a more typical 40,000. Maunder was a driving force in the foundation of

the British Astronomical Association, and was a fellow of the Royal Astronomical

Society.

Solar activity fluctuates on an 11 year cycle with 1996-2007 period being the last complete cycle. Since then the sun has been relatively quiet. This lack of activity may signal the beginning of a period of minimum sunspots and some sources (see for example "Ray of Hope. Can the sun save us from global warming?" in "The Independent" science report of December 5, 2007) has suggested that if the sun remains quiet for another year or two, it may indicate a return to a period of dramatic cooling of the Earth, similar to that which occurred during the last Maunder Minimum. However, the latest solar data (see below) indicates that this in not likely at the present time.

Dr David Whitehouse who is the author of the book "The Sun: A Biography" published by Wiley, has an informative article in the "Independent" of April 27, 2009. The article is headed "The missing sunspots: Is this the big chill? For details see

http://www.independent.co.uk/news/science/the-missing-sunspos-is-this-the-big-chill-1674630.htm!

Latest Sunspot Data

The NASA Solar Physics web site ( see http://solarscience.msfc.nasa.gov/ includes information on sunspot numbers, the "Maunder Minimum" and Sunspot Cycle predictions. The NOAA sunspot index is updated monthy and available from 1749.

For a graphical display of the sunspot index, the Maunder "butterfly" diagram, and other solar matters from the Royal Observatory of Belgium, see http://sidc.oma.be/sunspot-index-graphics/sidc_graphics.php

For the current information on sunspots see http://spaceweather.com. In 2009 the sun had no spots 71% of the time, which was the lowest number for any year for 95 years.

Updated: January 8, 2013