What do the numbers 923, 930, 935, 941 and 944 have in common? Answer: They’re different names for the same sunspot, this one shown above.
Greg Piepol of Rockville, Maryland, took the picture yesterday using a Solar Max Solar telescope/camera. It shows sunspot 944 coming around the sun’s eastern limb–for the fifth time! Usually sunspots form and dissolve in a matter of weeks, but this spot has endured for more than five 27-day solar rotations. By long and idiosyncratic tradition, a sunspot receives a new number each time it reappears and is visible to earth.
Sunspot 944 may not seem impressive now, but one month ago as “941” it was a lovely spiral. Three months ago as “930” it produced one of the strongest solar flares of the past 25 years and Northern Lights as far south as Arizona. What will it do this time?
Even though we are in between peaks in our 11 year sunspot cycle, we still seem to have quite an active sun. The trend over the last century has been that our solar cycle has had more activity than centuries before.
Of course, that couldn’t possibly have anything to do with global warming.