Since rotating into view, the sunspot group AR12192 has continued to grow in size and complexity, becoming the largest sunspot of the current solar cycle, cycle 24 (SC24.) The region has produced numerous C and M-class flares including an X1 flare.
As of Oct. 22, 2014 (11 UT) the region’s trailing spots have an area of 2410 MH or millionths of a visible solar hemisphere. The largest sunspot up until now had been AR11967 on Feb. 5, 2014, measuring 1580 MH. MH is a standard measure used by astronomers for sunspot area. A sunspot that measures 300-500 MH is generally considered big. Just to provide some scale, the surface area of Earth is 169 MH. This means that AR12192 is 14 times larger than the surface area of Earth.
|Year||Month||Day||Active Region #||Area (MH)||Largest Flare|
A famous giant sunspot is AR9393. On March 29, 2001, the region measured 2440 MH, just slightly bigger than AR12192.
But even this monster spot is not the biggest. Two larger sunspots of note are the spot of March 1989 that triggered the infamous geomagnetic storm that crippled the Quebec, Canada power grid and the Great Sunspot of 1947, which came in at a whopping 6000+ MH or 3 times AR9393. David Hathaway of the NASA Marshall Space Flight Center solar physics group created a graph showing the size of the largest individual sunspots each year from 1900 to 2000.