Maunder Minimum

padre31 · May 6, 2009

Although sunspots were observed telescopically in 1611, it was not until 1843 that an amateur German astronomer, Heinrich Schwabe, noticed a periodic rise and fall in their numbers. That it took over 200 years for astronomers to notice something so seemingly obvious is some cause for wonder, but it may be partly explained by the nearly complete absence of sunspots for 70 of those years, between 1645 and 1715.

For reasons not yet understood, the solar cycle operated at a greatly reduced amplitude during that time. Evidence suggests it did not cease entirely, but the sunspot number—an index representing the total level of sunspot activity at a given time—during the late 1600s was reduced by a factor of 10-20 from its typical value during "normal" cycles. This perplexing aspect of the sunspot record was formally pointed out by the astronomers F. W. G. Sporer and E. H. Maunder in 1890, and it is now known as the Maunder minimum.

The existence of the Maunder minimum is interesting on purely astrophysical grounds, because it suggests that the regular rise and fall of sunspots observed from 1715 all the way through to the present day may not be a permanent, or even typical, aspect of solar behavior. It is possible to create a rough reconstruction of the sunspot record prior to the invention of the telescope, using indirect indicators of solar activity, and there is evidence for other Maunder minimum-like periods intermittently from about A.D. 1250 through 1715. The solar cycle as observed today, is therefore not the state in which the Sun spends all—or even most—of its time. Having only observed one Maunder minimum, we have no idea whether the Sun spends 10%, 50%, or 90% of its time in such a state.
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Interesting, prior to that, Iceland was literally ice locked and separated from Europe for 70 years due to the cold, but that was much earlier in Western History then the little ice age.

This is the perhaps more relevant to today's world:

http://www.ibdeditorial.com/IBDArticles.aspx?id=287279412587175

Kenneth Tapping, a solar researcher and project director for Canada's National Research Council, is among those looking at the sun for evidence of an increase in sunspot activity.

Solar activity fluctuates in an 11-year cycle. But so far in this cycle, the sun has been disturbingly quiet. The lack of increased activity could signal the beginning of what is known as a Maunder Minimum, an event which occurs every couple of centuries and can last as long as a century.

Such an event occurred in the 17th century. The observation of sunspots showed extraordinarily low levels of magnetism on the sun, with little or no 11-year cycle.

This solar hibernation corresponded with a period of bitter cold that began around 1650 and lasted, with intermittent spikes of warming, until 1715. Frigid winters and cold summers during that period led to massive crop failures, famine and death in Northern Europe.
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