Although the Sun may be in the midst of the weakest solar cycle in a century, a very large sunspot group (number AR 1944) recently made its way across the solar disc. AR 1944 was first noted on December 31, 2013, and exited the solar disc on January 13, 2014. The group spanned an impressive 200,000 kilometres, and the umbra (the darkest region) of the biggest spot alone was considerably larger than the Earth.
The Sun undergoes an 11-year cycle, during which the number of sunspots climbs to a peak before settling down for solar minimum. In theory, at least, solar activity is at its maximum for the current cycle right now — though sunspot numbers have been very low. Not all solar maximums are created equal, however, and the relative quiet of this one is likely a feature of normal, long-term, cycle-to-cycle variations.
