WE HAVE KNOWN ABOUT AND OBSERVED SUNSPOTS FOR HUNDREDS OF YEARS

They’re coming again! In fact activity on our sun began early in January. This activity is called sunspots and they produce solar storms. During a solar storm highly charged particles ejected from the sun may head toward Earth, where they can bring down power grids, disrupt communications and even threaten our astronauts and satellites with harmful radiation.

A sunspot is a region on the Sun's surface (photosphere) that is marked by a lower temperature than its surroundings and has intense magnetic activity. Although they are blindingly bright at temperatures of roughly 4000-4500 K, the contrast with the surrounding material at about 5800 K leaves them clearly visible as dark spots. Sunspots are often related to intense magnetic activity. Most solar flares and coronal mass ejections originate in magnetically active regions around sunspot groupings. Sunspot numbers rise and fall with an irregular cycle with a length of approximately 11 years. 

The Sun was last similarly active over 8,000 years ago. The number of sunspots has been found to correlate with the intensity of solar radiation over the period (since 1979) when satellite measurements of radiation are available.  During the Maunder Minimum in the 17th Century there were hardly any sunspots at all. This coincides with a period of cooling known as the Little Ice Age.

Apparent references to sunspots were made by Chinese astronomers in 28 BC (Hanshu, 27), who probably could see the largest spot groups when the sun's glare was filtered by wind-borne dust from the various central Asian deserts. The Wilson effect tells us that sunspots are actually depressions on the sun's surface. Sunspot lifetime is about two weeks. Sunspot activity cycles about every eleven years. Solar storms, as they are called, will reach maximum activity by 1011 or 2012.