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.