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Related to sunspot: Sunspot cycle


1. any of the dark cool patches, with a diameter of up to several thousand kilometres, that appear on the surface of the sun and last about a week. They occur in approximately 11-year cycles and possess a strong magnetic field
2. Austral a small cancerous spot produced by overexposure to the sun



a dark formation observed in the photosphere of the sun. The diameters of sunspots can be as large as 200,000 km, and the temperatures are not greater than 4500°K. Since the temperature of the photosphere is 1,000 to 2,000 degrees higher than that of sunspots, the photosphere is two to five times brighter than the spots. The mean annual number of sunspots varies with a period of 11 years.


Bray, R., and R. Loughhead. Solnechnye piatna. Moscow, 1967. (Translated from English.)


A dark area in the photosphere of the sun caused by a lowered surface temperature.
References in periodicals archive ?
Caption: SUNSPOT CLOSE UP Twisted, concentrated field lines poking out of the solar surface keep surrounding convective plasma (bright orange) from flowing into their locations, creating local cool spots that we see as sunspots.
A Comparison of Rome Observatory Sunspot Area and Sunspot Number Determinations with International Measures, 1958-1998, NASA/TP-2005-214191, NASA Marshall Space Flight Center, Huntsville, AL, 20 pp.
An almost continuous line of CaK plage was observed for about 60[degrees] east-west at a latitude between S05[degrees] and S10[degrees] from Aug 17 to 20, linking plage around the sunspot groups in that region.
For those who require additional illustrations, sunspots and faculae provide an interesting proving ground.
The transit will be particularly exciting if lots of sunspots are visible at the same time.
Around 2020, sunspots may disappear for years, maybe decades.
The last major occasion of this was between 1645-1715, when no sunspots on the sun's surface appeared during a 70-year-period.
There was a period from 1645 to 1715 when the sun showed similar lack of sunspots, this was the Maunder minimum when trees stopped growing and the River Thames froze.
who has tracked sunspot intensities from different spots around the globe dating back four centuries, also concludes that such solar disturbances have little or no impact on global warming.
By comparison, AeroLEDs says the nominal life of its SUNSpot is 50,000 hours running at a current of about 2 to 3 amps.
Conference on Solar MHD Theory and Observations; a High Spatial Resolution Perspective (2005: Sunspot, New Mexico) Ed.
The most striking feature of the complete SN [sunspot number] profile is the uniqueness of the steep rise of sunspot activity during the first half of the 20th century.