B.C. It is interesting to look at the progression of all the recent solar flux numbers, including the morning and afternoon readings. Beginning at 1700z on March 18, and running through 2300z Thursday, March 29, they were 135.3, 139.8, 143.1, 145.4, 147.0, 147.9, 157.2, 153.3, 158.1, 154.2, 159.4, 160.3, 180.4, 183.0, 184.0, 178.9, 180.0, 179.8, 201.1, 218.7, 216.6, 248.9, 216.8, 229.5, 247.6, 263.7, 261.1, 271.6, 273.4, 276.3, 272.4, 273.5, 293.8, 261.0, 261.7, and 276.1. Sunspot numbers also went very high this week, peaking at 352 on Wednesday. This is not a record for cycle 23, which had a higher sunspot number of 401 on July 20, 2000. The cause of all this excitement is an explosion in the number and size of sunspots recently, the largest being region 9393, which is the largest sunspot to appear in the last 10 years.
Astronomers rate the size of sunspots in terms of millionths of the sun's earth- facing hemisphere.
A big sunspot measures 300 to 500 millionths, and 9393 registered about 2400 millionths on March 29. The biggest spot of the current cycle, until now, was 9169 which measured 2140 millionths on September 20, 2000. There is also a statistic for the total area of all the visible spots, and that has been growing steadily and is still growing. The high A indices of last week are back again, and there is more activity predicted for the next few days due to a coronal mass ejection from sunspot 9393 on Wednesday. The probable planetary A index for Friday and Saturday is 50, dropping to 30 on Sunday and 15 on Monday.